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Relation of the reproductive biology of plants to the structure and function of four plant communities Pojar, Jim 1974

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C- I  THE RELATION OF THE REPRODUCTIVE BIOLOGY OF PLANTS TO THE STRUCTURE AND FUNCTION OF FOUR PLANT COMMUNITIES  by  JIM POJAR B . S c , U n i v e r s i t y o f M i n n e s o t a , 1969 M.Sc. , U n i v e r s i t y o f M i n n e s o t a , 1970  A THESIS SUBMITTED IN.PARTIAL  FULFILMENT OF  THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  i n t h e Department of Botany  We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e required standard  THE UNIVERSITY OF BRITISH COLUMBIA  In p r e s e n t i n g t h i s  thesis  an advanced degree at  in p a r t i a l  further  for  the  requirements fn  freely  available  for  t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f  representatives.  this thesis for  It  financial  is understood that copying or gain s h a l l not  w r i t ten pe rm i ss i on .  Department  of  "\j>  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada  Date  °\LaAX  \ , VH  *r  that  reference and s t u d y this  thesis  s c h o l a r l y purposes may be granted by the Head of my D e p a r t m e n t  by h i s of  agree  of  the U n i v e r s i t y of B r i t i s h Columbia, I a g r e e  the L i b r a r y s h a l l make it I  fulfilment  or  publication  be allowed without my  Abstract  Four p l a n t communities were s t u d i e d i n an  attempt  of southwestern B r i t i s h  Columbia  t o answer the f o l l o w i n g  related  questions: (1)  do  communities  any (2)  of harsh  characteristic  p h y s i c a l environments  exhibit  phytosociological features?  are there  any  correlations  harshness  and  certain  between  environmental  synecological properties of  such  communities ? (3)  are species  of such communities  specializations  that tend  selected for reproductive  to reduce  their  genetic  variability? The or  f o u r communities semi-shrubby  sphagnum b o g s , In this (a)  vegetation) and  investigation  first  less  specific  competition  m a r s h , two  questions, the  and  as  and  inter-  increases.  i n c r e a s e as  with  f i n d i n g s of  proceeds  correlation,  environmental  both  negative  heterogeneity  increase.  of p o l y p l o i d y w i t h i n communities  correlated  coastal  physical stress increase,  succession  a s s o c i a t i o n and  and  herbaceous  s t r u c t u r e becomes more a g g r e g a t e d  competition  positive,  of  meadow.  heterogeneity  and  types  that:  a g g r e g a t e d as  (b) i n t e r s p e c i f i c  levels  two  indicate  species population  and  were a s a l t  a subalpine  answer t o the  environmental  (c)  (representing three  environmental  rigor  appear  to  be  (broadly defined).  (d)  the  most a b u n d a n t  species  most v a r i a b l e and niche  size  specific (e) w i t h i n  and  a community  p r e s u m a b l y have t h e  population  competition  are  the  l a r g e s t niches ;  variability  d e c r e a s e as  inter-  increases.  a community, e c o l o g i c a l d i s t i n c t i v e n e s s r e d u c e s  interspecific stress  within  competition;  communities  ( e s p e c i a l l y seasonal  ecologically  dissimilar  species  diversity  s t r e s s ) have t h e  least  most  species.  1  ( f ) dominance d e c r e a s e s as  under the  species  i s roughly  diversity  increases,  correlated with  and  overall  environmental s e v e r i t y . In (a)  (b)  answer t o t h e  a l l four  last  communities  question: are  outcrossing  species;  pollination  or apomixis  an  d o m i n a t e d by  there  i s no  i n any  o f the  to which there  i s no  potential  recombination,  on  Plant  four d i f f e r e n t  communities  and  to evolutionary  different  r a t e s , and  communities.  and  evolutionary  their  (mesic, zonal)  often  more o r  in different  difference in species  and  species less  both  independently,  or even  opposite  a powerful e f f e c t  on  the  communities, but  in  an  is l i t t l e  environments  biology,  a v e r a g e , between  constituent  f o r c e s , but  function of plant sense there  devised,  significant  the  self-  communities.  ways. E n v i r o n m e n t a l s t r e s s has structure  to  of r e p r o d u c t i v e  according  of the  at  major s h i f t  i n d e x o f p o t e n t i a l r e c o m b i n a t i o n was  embodying a number o f a s p e c t s  respond  predominantly  d i f f e r e n c e between  extreme or  azonal  normal  environments  t o an i n d i v i d u a l been o p e r a t i n g  species. D i f f e r e n t s e l e c t i o n pressures  in salt  marshes,  meadows, b u t t h e p r e s e n t the  study  resultant evolutionary  communities  are  equivalent.  sphagnum b o g s , and  have  subalpine  i n d i c a t e s t h a t , on t h e a v e r a g e ,  s t r a t e g i e s o f the species  of  these  TABLE OF CONTENTS  Section I II  Page Introduction  1  Description  5  A. Sampling  methods  5  B. Sampling r e s u l t s  7  C. V e g e t a t i o n o f t h e f o u r communities  III  10  S a l t marsh  10  Sphagnum bogs  14  S u b a l p i n e meadow  19  Theory and Results  23  A. P o p u l a t i o n s t r u c t u r e o f i n d i v i d u a l s p e c i e s (D/d i n d e x o f a g g r e g a t i o n ) B. I n t e r s p e c i f i c r e l a t i o n s h i p s Association X  2  and C o l e ' s i n d e x o f a s s o c i a t i o n  Species c o n s t e l l a t i o n s Corre l a t d o n x:  23 30 30 30 33 40  C. Chromosome numbers and p o l y p l o i d y  51  D. F l o w e r i n g phenology  69  E. P o l l i n a t i o n ecology  73  F. D i s p e r s a l e c o l o g y G. Vapiability^'and-v'niche--w-id-th.  115 12 7  H. N i c h e d i f f e r e n t i a t i o n  136  I . Dominance, d i v e r s i t y , and s t a b i l i t y  147  J . Index o f p o t e n t i a l r e c o m b i n a t i o n  159  vi. Section IV V  Page Summary, D i s c u s s i o n , and C o n c l u s i o n s  190  Literature Cited  202  Appendix 1.  Species  lists  227  Appendix 2. Summary o f some s t a t i s t i c s Appendix 3. Summary o f r e p r o d u c t i v e each s p e c i e s  234  biology of 288  vii.,  LIST OF TABLES  TABLE  Page  1  Summary o f v e g e t a t i o n sampling  2  Mean number o f s p e c i e s p e r quadrat f o r t h e v a r i o u s  6  quadrat s i z e s 3  8  Frequency, mean c o v e r , and importance v a l u e s o f the v a s c u l a r p l a n t s p e c i e s o f t h e S a l t Marsh  4  10  Frequency, mean c o v e r , and importance v a l u e s o f t h e v a s c u l a r o p l a n t s p e c i e s o f Wade's Bog  5  15  F r e q u e n c y , mean c o v e r , and importance v a l u e s o f t h e v a s c u l a r p l a n t s p e c i e s o f Ogg's Bog  6  16  Frequency, mean c o v e r , and importance v a l u e s o f t h e v a s c u l a r p l a n t s p e c i e s o f B l a c k w a l l Meadow  21  7  D/d i n d e x o f a g g r e g a t i o n  25  8  Weighted average community D/d v a l u e s  29  9  Summary o f s p e c i e s i n t e r a c t i o n s  47  10  Chromosome numbers, p o l y p l o i d y , and importance v a l u e s of s p e c i e s o f t h e f o u r study communities....  60  11  Summary o f l e v e l s o f p o l y p l o i d y  66  12  Community mode o f p o l l i n a t i o n as p e r c e n t a g e o f t h e f l o r a and v e g e t a t i o n  73  13  Outline of diaspore types  116  14  Percentages  of diaspore types  117  15  Percentages  o f d i s p e r s a l methods; f l o r a / v e g e t a t i o n . 121  16  Morphological v a r i a t i o n i n nine grass species  131  17  E c o l o g i c a l unit characters  138  viii, TABLE  Page  18  Number o f s p e c i e s , two i n d i c e s  o f d o m i n a n c e , and an  index o f d i v e r s i t y f o r the four  study  c o m m u n i t i e s . . 149  19  Index o f P o t e n t i a l  Recombination  175  20  A v e r a g e community  21  Combinations o f opposing r e g u l a t o r y f a c t o r s  185  22  Results  191  I.P.R.'s  183  and i n d i c a t i o n s  LIST OF FIGURES Figure  Page  1  Modified  species-area  curves  ••  2  Salt  Marsh  12  3  Salt  Marsh  12  4  Deschampsia  5  Wade's Bog. i  13  6  B l a c k w a l l Meadow  20  7  B l a c k w a l l Meadow  20  8  Salt  33  9  Wade's Bog - s p e c i e s  cespitosa  9  13  Marsh - s p e c i e s c o n s t e l l a t i o n constellation  35  10  Ogg's Bog - s p e c i e s c o n s t e l l a t i o n  36  11  B l a c k w a l l Meadow - s p e c i e s c o n s t e l l a t i o n  38  12  Frequency d i s t r i b u t i o n s  49  13  .Number:, o f . v a r i a b l e  of correlation  pairs  cespitosa,  v s . Ar  49  14  Deschampsia  15  Festuca  16  Triglochin  maritimum,  n - 48  53  17  Salicornia  virginica,  n = 18  53  18  Plantago  rubra,  n - 13  coefficients  n = 21  maritima,  53 53  n - 6  53  Figure  Page  19  Junaus  20  Cavex  lyngbyei  21  Glaux  mavitima  22  Potentilla  23  Agvostis exavata n--  24  Stellavia  humifusa  25  Tvifolium  wovmskjoldii  26  Scivpus  27  Puccinellia  pumila  28  Spergularia  canadensis  29  Hordeum  30  Lilaeopsis  occidentaHs  31  Myrica.  3  32  Apavgidium  33  Cavex  34  Cavex p l u v i f l o v a  35  Agvostis aequivalvis  36  Sanguisovba  37  Ledum  38  Vaccinium  39  Dvoseva  40  Kalmia  41  Empetvum  42  Tvientalis  43  Cavex  44  Tofieldia  45  Linnaea bovealis  balticus  n = 40  3  3  3  n = 36  53  n = 15  53  pacifica  n - 14  3  3  53  n = 13  53  n - 16  3  53  n = 30  3  53  n = 21  3  brachyanthevum  gale  53  14.  3  cevnuus  53  3  3  53  n = 18  53  n - 14  53  3  n = 22  53  n - 48  boveale  obnupta  54 n - 9  3  n = 37  3  54  n - 26  3  gvoenlandicum  3  oxycoccus  3  votundif'olia polifolia nigvum  54  n = 7  3  officinalis  3  3  54  n = 24..•  54  n - 10  n = c a . ~42-44  3  n = 28  3  glutinosa 3  3  54  n = 13  n = 13  3  54  n - 14  n = 12  3  avctica  c a n e sc ens  54  n = 15  n = 16  •  54 54 54 54 54 54 54  Figure 46  Rhynchospora  47  Vlantago  48  Gaultheria shallon  49  Gentiana  50  Calamagrostis  51  Maianthemum  52  Sairpus  cespitosus  53  Coptis  asplenifolia  54  Coptis  trifolia  55  Junous  supinif'ormis  56  Gentiana  57  Vaccinium  ovatum  58  Vaooinium  vitis-idaea  59  Vaooinium  uliginosum  60  Nephrophyllidium  61  Eriophorum  62  Carex p a u o i f l o r a  63  Valeriana sitohensis  64  Lupinus  latifolius  65  Festuca  viridula  66  Erigeron peregrinus  67  Anemone  68  Erythronium  69  Votentilla  70  Vaooinium  sooparium  71  Claytonia  lanoeolata  72  Arenaria  alba  n  - 13  3  n  3  maorooarpa  = 44  n  3  - 12  nv - 13  soeptrum,  nutkaensis  dilatatum  n  18  =  52 9....  -  - 9 = ca.  n  3  douglasiana  n  3  n  3  14  = ca.  3  n  3  n  3  n  3  n =  3  56  13  =  12....  -  n  3  =  n  3  12  =  24  orista-galli  polystachion 3  37  n = ca.  3  48  - 14  n  n  3  ocoidentalis  9...  2n  3  flabellifolia n  3  3  n  2n n  3  -  -  12  = 2n  3  16  -  grandiflorum,  oapillaris  48  = ca.  n  3  30  =  - ca.  n  3  n  3  n  3  =  16 11  24 14  Figure 73  Antennavia  lanata,  74  Veronica  cusickii,  75  Agoseris  aurantiaca,  76  Phleum alpinum  77  Arnica  latifolia  78  Luzula  h i t c h c o e k i i , n - 12  79' T h a l i c t r u m  n - 14.. n =  n - 18  n =  3  36..  14....  n = 19..  3  occidentale  n - 28  3  80  Achillea millefolium  81  Trisetum  82  Elymus  83  Silene parryi  84  A r n i c a m o l l i s , n = ca.  85  Penstemon procerus  86  Poa c u s i c k i i  87  Senecio  88  Eieracium  89  Luzula  90  Sedum  91  Castilleja  92  Pedicularis bracteosa  93  Phlox  94  Potentilla  95  Carex  96  Epilobium  97  Delphinium  n u t t a l l i a n u m , n = 16  98  Castilleja  parviflora,  99  Ranunculus  e s c h s c h o l t z i i , n - 16  spicatum  glaucus  n =  3  14...  n = 24  3  38...  n =  3  8...  n - 14  integerrimus gracile  spicata  27  n = 14  3  3  n -  3  3  n =  3  n -  3  20  9..  n = 12....  lanceolatum  n =  3  miniata  8..  n = 12  3  3  n - 8  diffusa, n - 7 diversifolia,  spectabilis; alpinum,  n - ca.  n = c a . 42 n =  18....  n = 12  xii. Figure  Page  100  Sibbaldia procumbens  101  Junous  102  Eydrophyllum  103  Senecio  104  Vaooinium  105  Mitella pentandra  3  n - 7  58  106  Luetkea pectinata,  n - 9  58  107  P e d i c u l a r i s racemosa,  108  Phyllodoce  109  Veratrum  viride  110  Veronica  wormskjoldii  111  F l o w e r i n g phenology  112  Spergularia  113  Drosera  s e l f - p o l l i n a t i n g flower  75  114  P o t e n t i l l a f l a b e l l i f o l i a , bowl-shaped b l o s s o m  77  115  Plantago  drummondii,  n - 7  3  n - ca.  fendleri  3  triangularis deliciosum  3  3  60  58  n = 18  58  n - 20  58  n - 24  58  n - 8  empetriformis 3  3  58  n = 24  58  n - 16  58 n - 9  3  58 7 0  canadensis,  rotundifolia  maritima,  58  3  self-pollinating flower....  strongly protogynous,  anemophil-  ous f l o w e r s  77  116a S a l i c o r n i a v i r g i n i c a  3  flowers  116b S a l i c o r n i a v i r g i n i c a , f l o w e r s 117  Juncus  i n female  stage......  i n male s t a g e  b a l t i c u s , s t r o n g l y protogynous,  Scirpus  82 82  anemophilous  flowers 118  75  83 c e s p i t o s u s , strongly protogynous,  anemo-  philous flowers  83  119a T h a l i c t r u m  o c c i d e n t a l e , male f l o w e r s  119b T h a l i c t r u m  occidentale,  120  Sanguisorba  121  Trientalis  officinalis,  female  flowers  fly-pollinated flowers....  a r c t i c a , f l y - p o l l i n a t e d flowers  86 86 87 87  xiii. Figure  Page  122  Coptis  123  Veratrum  124  Nephrophyllidium  f l y - p o l l i n a t e d flower  89  , f l y - p o l l i n a t e d flowers  89  tvifolia, viride  crista-galli,  carrion  fly-polli-  nated flower 125  Lysiehitum  91 mephitic, carrion  americanum,  fly-polli-  nated f l o w e r s 126  91  cusiokii,  Veronica  f l o w e r s p o l l i n a t e d by s y r p h i d  flies  92  127  Valeriana  sitchensis  128  Apargidium  boreale  129  Erigeron  130  Glaux  131  Delphinium  , "cornucopian" , "cornucopian"  peregrinus, maritima,  132a Gentiana  flowers  92  flowers  94  "cornucopian" flowers  ant-pollinated  94  flowers  96  n u t t a l i i a n u m , bombophilous f l o w e r s  96  view i n t o i n t e r i o r o f a bombo-  sceptrum,  philous flower 132b Gentiana 133  Lupinus  98  sceptrum,  closed flowers i n r a i n y weather. bombophilous f l o w e r s w i t h p i s t o n  latifolius,  mechanism of p o l l e n p r e s e n t a t i o n 134  Pedicularis  100  b r a c t e o s a , bombophilous f l o w e r s w i t h  short-beaked galeas 135  Pedicularis twisted,  136  137  Pedicularis  10 0  r a c e m o s a , bombophilous f l o w e r s w i t h long-beaked  galeas  10 2  g r o e n l a n d i c a , bombophilous f l o w e r s w i t h  extremely long-beaked  galeas  Gentiana  white flowers w i t h blue  douglasiana,  10 2 nectar  guides 138  Vaccinium  98  104 ovatum,  urceolate,  light-pink flowers....  104  Figure 139  Page Vacoinium  oxycoccus  }convergent 140  D'ode oath  eon  floral  e v o l u t i o n . . . . 106  j effr^yi  141a S i l e n e  parryi  (day)  108  141b S i l e n e  parryi  (night)  108  142  Agoseris  a u r a n t i a c a , butterfly-pollinated  143  Phlox  144  Castilleja  145  Anemone  146  Empetrum  147  P l a n t a g o macrooarpa  148  Carex  f l o w e r s . . HO  d i f f u s a , b u t t e r f l y - p o l l i n a t e d flowers mini at a,  110  hummingbird-pollinated flowers.  o o c i d e n t a l i s , wind-dispersed f r u i t s nigrum,  lyngbyei  112  i n black-berried fruit  120  , f r u i t i n g spike  120  , f r u i t i n g spike of t h i c k - w a l l e d  perigynia 149  Coptis  112  asplenifolia,.follicles  123 adapted f o r  splash-  cup d i s p e r s a l  123  150  I . V . vs. C V . f o r nine species  of grasses  151  Strength of i n t e r s p e c i f i c competition vs.  133 average  ecological distinctiveness  146  152  Dominance - d i v e r s i t y c u r v e s  148  153  D.I.  , N vs. H' , X  . 150  XV.  Acknowiedgements  I thank Dr. K.I. Beamish f o r her supervision, of t h i s project-, and f o r reading, the thesis throughout, i t s production,, keeping, a c r i t i c a l eye and l o g i c a l r e i n on i t s developments Discussions with Drs. R, Cruden, R. Foreman, J . Maze, G. Person, P, Raven, W, Schofield, G. Scudder, and R, Taylor were h e l p f u l . Thanks are extended to Dr. G. Eaton and Mrs. D,. l a u r i e n t e for writing computer programs,, and to H.E. M i l l i r o n , Canada Dept. of A g r i c u l t u r e , f o r i d e n t i f y i n g some bumble bees. I much appreciated the use of equipment, belonging, to Drs.  R. Foreman, V. K r a j i n a , C. Marchant, and G. Scudder,  and the housing and l o c a l guidance provided i n T b f i n o by Mr. A. Guppy. My brother,, Jerry, d i d good work as f i e l d  assistant  i n 1971, and took most o f the photographs i n the thesis;. The f i e l d work was done with the cooperation of the National and H i s t o r i c Parks Branch, Department of Indian A f f a i r s and Northern Development-, Canada, and the B r i t i s h Columbia Department of Recreation and Conservation, Parks Branch. The research was supported by the Committ.ee on Research, U n i v e r s i t y of B r i t i s h Columbia, Grant 219554 to Dr. K.I.. Beamish, by a Grant.-in-Aid from the Society of the Sigma X i , by a Univ. of B r i t i s h Columbia Graduate fellowship, and by the Department, of. Botany, Univ. of B r i t i s h  Columbia..  1 I.  INTRODUCTION  Intimations of i n t e r r e l a t i o n s  and c o r r e l a t i o n s between  the  r e p r o d u c t i v e b i o l o g y o f a s i n g l e s p e c i e s and the type o f community i t grows i n have been s u r f a c i n g i n the r e c e n t literature  o f e v o l u t i o n , e c o l o g y , and s y s t e m a t i c s .  gnomic  As the  fields  o f taxonomy, e c o l o g y , p o p u l a t i o n b i o l o g y , b i o g e o g r a p h y , and e v o l u t i o n a r y b i o l o g y , f o r m e r l y s e p a r a t e mainstreams organism b i o l o g y , impinge more and more upon one c e r t a i n m u l t i d i s c i p l i n a r y questions  o f whole  another,  are b e i n g posed. For example,  i n v e s t i g a t i o n s by S a l i s b u r y ( 1 9 4 2 ) , Grant ( 1 9 5 8 ) , C a r l q u i s t ( 1 9 6 6 ) , Mosquin ( 1 9 6 6 ) , R o l l i n s  ( 1 9 6 7 ) , Ornduff ( 1 9 6 9 ) , W e l l s  ( 1 9 6 9 ) , Whitehead ( 1 9 6 9 ) , Kevan ( 1 9 7 0 ) , B a k e r , Cruden, and Baker ( 1 9 7 1 ) , Baker ( 1 9 7 2 ) , and S a v i l e (1972) have d e a l t , d i r e c t l y o r i n c i d e n t a l l y , w i t h the r e l a t i o n s h i p between  either certain  f e a t u r e s o f the r e p r o d u c t i v e b i o l o g y o f angiosperms and the n a t u r e o f the p l a n t community. Other s t u d i e s have sought integrate  to  r e p r o d u c t i v e and p o p u l a t i o n b i o l o g y ( e g . , L e v i n and  Anderson 19 70; McNaughton and Wolf 19 70; Bradshaw 1971, 19 72; Mosquin 1971; B e a t t i e , B r e e d l o v e , and E h r l i c h 1973; and a number o f papers by D . A . L e v i n and b y ^ L e v i n M H ^ W v ^ K e r s t e r , d  w  a  E c o l o g i c a l f e a t u r e s e i t h e r found o r t o be expected i n c e r t a i n t y p e s o f v e g e t a t i o n have been e l u c i d a t e d by G r e i g - S m i t h (19 6 4 ) , Kershaw ( 1 9 6 4 ) , Smith and Cottam ( 1 9 6 7 ) , Odum ( 1 9 6 9 ) , Byer  (1970),  M c i n t o s h ( 1 9 7 0 ) , and McNaughton and Wolf ( 1 9 7 0 ) .  Furthermore,  Baker ( 1 9 6 6 a ) , H a r p e r ( 1 9 6 7 ) , L a n g f o r d and B u e l l  (1969),  M c i n t o s h (19 7 0 ) , and W h i t t a k e r and Woodwell (1972) commented ( w i t h somewhat d i f f e r e n t  interpretations)  have on p r o p e r t i e s  2 of  coordination,  interdependence,  communities, properties evolutionary Most  of  the  stimulus that  implications above p a p e r s  for this  w h a t was  exhibit  Do any  (2)  has  a  homeostasis  the  community  plant  and  individually  collectively  synthetic  to  the  approach.  been addressed  to  communities  harsh  of  in  important e c o l o g i c a l  for both  s t u d y , and  plant  three  to  and  i t s  species.  the  initial  realization  Therefore,  related  physical  the  questions:  environments  characteristic"phytosociologieal features?  Are  harshness  have  contributed  n e e d e d was  investigation (1)  that  and  there  and  any  c o r r e l a t i o n s between  certain synecological  environmental  properties  of  such  communities ? (3) ductive ary  Are  of  such communities  specializations that  theory) Four  or  species  tend  to  reduce  communities  semi-shrubby  meadow) u s u a l l y t h o u g h t  described ecology.  by The  the  (salt as  as  first  study  (1)  species  population  (2)  interspecific  three  types  of  evolution-  herbaceous  areas,  i n extreme and  methods of or  repro-  established  m a r s h , sphagnum bog,  standard  two  to  for  variability?  occurring  following concepts  t o b e a r upon the  a. )  of  chosen  some o f  genetic  representing  vegetation  environments were  (according  selected  their  subalpine  physical vegetation  descriptive  disciplines  were then  plant brought  questions: structure  relationships within  communities  association  b. ) c o r r e l a t i o n (3)  community  l e v e l s of  (4)  community p a t t e r n s  polyploidy of  flowering  phenology,  pollination  3  e c o l o g y , and d i s p e r s a l e c o l o g y  (5) the t h e o r y o f the n i c h e and c o r o l l a r i e s d e a l i n g w i t h n i c h e s i z e , p o p u l a t i o n v a r i a b i l i t y , and n i c h e d i f f e r e n t i a t i o n (6) dominance, d i v e r s i t y , and s t a b i l i t y . R e g a r d i n g the t h i r d q u e s t i o n , Mosquin (19 66) has recommended t h a t " I f we w i s h t o d i s c o v e r whether o r not d i f f e r e n t  floristic  o r e c o l o g i c a l zones have s i g n i f i c a n t l y d i f f e r e n t l e v e l s o f g e n e t i c v a r i a b i l i t y . . . t h e n t h e r e p r o d u c t i v e f a c t o r s i n each s p e c i e s o f a r e g i o n o r zone must f i r s t be i d e n t i f i e d and e v a l u a t e d . . . " The same l o g i c a p p l i e s t o v e g e t a t i o n t y p e s o r i n d i v i d u a l c o m m u n i t i e s . T h e r e f o r e , i n a t t e m p t i n g t o answer the t h i r d q u e s t i o n , d e t a i l s of the s p e c i e s ' b r e e d i n g systems have been worked out and s p e c i e s and community l e v e l s o f p o t e n t i a l recombination assessed. When I f i r s t s t a r t e d the i n v e s t i g a t i o n , I b e l i e v e d ( p a r t l y f o r the sake of argument) t h a t , i n o r d e r o f i n c r e a s i n g h a r s h ness o r r i g o r of t h e p h y s i c a l e n v i r o n m e n t , the study communities s h o u l d have been r a n k e d : s u b a l p i n e meadow, sphagnum b o g s ,  salt  marsh. W i t h t h i s r a n k i n g i n mind I expected c e r t a i n r e s u l t s . Some o f the e x p e c t a t i o n s were my own, o t h e r s were e i t h e r or i m p l i e d i n the l i t e r a t u r e . The i n i t i a l e x p e c t a t i o n s o u t l i n e d below ( d e t a i l s w i l l be g i v e n i n the s e c t i o n s o f the  stated  are  appropriate  thesis):  (1) S p e c i e s p o p u l a t i o n s s h o u l d be more aggregated  as  e n v i r o n m e n t a l h e t e r o g e n e i t y and p h y s i c a l s t r e s s i n c r e a s e ,  less  so as s u c c e s s i o n proceeds and i n t e r s p e c i f i c c o m p e t i t i o n i n c r e a s e s . (2) The s t r e n g t h s o f i n t e r s p e c i f i c a s s o c i a t i o n and c o r r e l a t i o n s h o u l d i n c r e a s e as p h y s i c a l s t r e s s , e n v i r o n m e n t a l  4 heterogeneity, (3) the  and  Levels  historical (4)  least  The  interspecific  of p o l y p l o i d y should than  the  and  dispersal  (5)  a.)  The  be  the  under the  competition  vectors,  be  lower  environmental  for flowering time,  species within a  most v a r i a b l e (have the  rigor.  have  the  pollination  decrease with  community  largest niche). niche  size  and  population  increasing competition  and  stress. c. ) W i t h i n  should the  with  agents.  most abundant  should  of  most s t r e s s s h o u l d  b. ) A v e r a g e w i t h i n - c o m m u n i t y variability  increase.  c o r r e l a t e d more  physical aspects  communities  interspecific  should  competition  reduce  least  a community, e c o l o g i c a l d i s t i n c t i v e n e s s  interspecific  stress should  competition;  have the  the  communities  most e c o l o g i c a l l y  under  dissimilar  species. (6) the  Species  community by  communities  relatively  of the  The  (8)  Communities of  toward  species  Finally,  study,  much o f t h e  be  few  g r e a t e s t , and  species weakest,  rigorous  with  dominance in  of  the  p h y s i c a l environments.  most d i v e r s e communities w i l l  genetic  comparisons  will  most b e n i g n  (7)  composed of  under  diversity  be  the  most s t a b l e .  p h y s i c a l environments w i l l  reproductive  specializations  be  tending  uniformity. I  should  add  t h a t , i n the  have u s u a l l y been c o n f i n e d i n a s m u c h as  there  investigation.  following exposition, to the  is little  or  no  four  communities  precedent  for  5  II.  A.  Four A  salt  Bog)  Methods of  sites  were  m a r s h and  were  two  chosen  Rim  M e a d o w ) was extensive Peak  15  site  discrete  the  same  a  of  spring  and  summer o f  Wade's Bog  Tofino,  on  Both bogs  subalpine  to  that  the are  to  stretches  north  The  referred to  located  unit  i s intended,  community concept.  c o m m u n i t y may  be  of  of  Similarly,  termed  of  in  the  Blackwall of  a  community.  existence  i n view  of  (Blackwall  a plant  a community's o b j e c t i v e  Ogg's  coast  vegetation  as  19 7 1 .  and  west  meadow s i t e  Nicomen Lake.  i s hereafter  over the  within  the  i n Manning P r o v i n c i a l Park, p a r t  vegetational  controversy  sampling.  (labelled  Columbia.  Park. A  miles  i m p l i c a t i o n as  species  vicinity  meadow v e g e t a t i o n  particular No  National  f o r about  during  sphagnum bogs  British  chosen  vegetation  sampled  i n the  Vancouver I s l a n d , Pacific  DESCRIPTION  as  the  a  widespread  groupings  a s s o c i a t i o n s , but  of  with  reservations.  All  communities were sampled w i t h  quadrats  located  by  2 random number p a i r s . C e n t r a l l y n e s t e d w i t h i n each 1 m quadrat, 2 2 a 50K-50 cm ( 0 . 2 5 m ) a n d a 1 0 x 1 0 cm ( 0 . 0 1 m ) q u a d r a t w e r e a l s o used.  P r e s e n c e and  vascular (I.V.)  plant  cover estimates  species  f o r each  species  i n each quadrat. was  frequency  and  addition,  e a c h c o m m u n i t y was  transects  30.5  3 0.5  cm  square  relative  cm  (1  were r e c o r d e d  cover  c a l c u l a t e d as ( K u r a m o t o and s a m p l e d by  f t ) wide.  q u a d r a t s was  An  Species  recorded  for  each  importance the  sum  Bliss  of  value relative  1970).  a c r i s s - c r o s s of occurrence  along  in  In belt  contiguous  these transects.  The  6 sampling  scheme  i s summarized  i n T a b l e 1.  sampling.  TABLE 1. Summary o f v e g e t a t i o n  Dimensions sampling (m)  Site  Salt  of  area  244x61  Marsh  transect  number o f  of quadrats  a  Sum o f  L e n g t h and  Number  transects  (m) l e n g t h  457.5  183 (2)  70  (m)  30.5 (3) 244  122 (1)  50  122x61  Wade's Bog  61 (2)  53x23  217  79.3 (1)  77  76x23  Ogg's Bog  46 (1)  b  23 (4) 122x61  Blackwall  244  122 (1)  50  61 (1)  Meadow  a  The  c o r r e s p o n d i n g a r e a s a r e a l l 8000-12000 m  D  Two r e c t a n g u l a r a r e a s  (0.8-1.2 h a ) .  a t an a n g l e t o one a n o t h e r , w i t h a  common c o r n e r .  A complete Appendix Herbarium  species l i s t  1. V o u c h e r s p e c i m e n s o f e a c h of the University  names and a u t h o r i t i e s except  f o r each  where  noted.  of British  site  c a n be f o u n d i n  s p e c i e s a r e on f i l e Columbia.  i nthe  A l lspecies  a r e as i n H i t c h c o c k et a l . ( 1 9 5 5 - 1 9 6 9 ) ,  7 B. Sampling r e s u l t s .  The number o f . s p e c i e s per quadrat f o r a l l quadrat s i z e s i s l i s t e d i n T a b l e 2. An i n t e r e s t i n g f e a t u r e 2  of these data i s that  a t the s m a l l e s t quadrat s i z e ( 0 . 0 1 m ) , the mean number o f s p e c i e s i s about the same f o r a l l f o u r communities. T h i s  suggests  t h a t the l o w e r l i m i t of t h e number o f s p e c i e s t h a t can be packed i n t o a givensspace_isaapproximate.ly-.the--. same:: f o r the  salt  marsh, b o t h sphagnum b o g s , and t h e s u b a l p i n e meadow. The g r e a t e r o v e r a l l " c a r r y i n g c a p a c i t y " o f the s u b a l p i n e meadow and bogs i s a f u n c t i o n o f a g r e a t e r degree o f .change i n s p e c i e s composi t i o n as quadrat s i z e i n c r e a s e s . T h i s change r e f l e c t s i n p a r t the g r e a t e r h a b i t a t and m i c r o t o p o g r a p h i c h e t e r o g e n e i t y o f the meadow and bogs. The s i t u a t i o n i s analogous (on a much s m a l l e r scale) to the increase i n between-habitat d i v e r s i t y that results  or beta  species  from an i n c r e a s e d change i n s p e c i e s  composition along environmental gradients  ( W h i t t a k e r 1969,  1970a, 1972). The m o d i f i e d s p e c i e s - a r e a c u r v e s o f F i g u r e 1 i n d i c a t e t h a t 2 the 1 m quadrats a c c u r a t e l y e s t i m a t e the t o t a l s p e c i e s c o m p o s i t i o n o f the c o m m u n i t i e s , s i n c e the c u r v e s l e v e l o f f 2 between the 0.45 and 1 m quadrat s i z e s . As quadrat i n c r e a s e s , the number o f d i f f e r e n t  size  s p e c i e s added w i t h s i z e  becomes p r o g r e s s i v e l y l o w e r . S p e c i e s - a r e a c u r v e s u s u a l l y p l o t  8  TABLE 2. Mean number of s p e c i e s p e r quadrat f o r t h e v a r i o u s 2  quadrat s i z e s . The 1 . 0 0 , 0 . 2 5 , and 0.01 m  quadrats 2  were randomly l o c a t e d ; t h e 0.45 and 0.09 m  quadrats  are t r a n s e c t segments.  lxl  Quadrat dimensions Quadrat  1.5x0.3  0.5x0.5  0.3x0.3  0.1x0.1  (m) 1.00  0.45  0.25  0.09  0.01  a r e a Cm )  S a l t Marsh  x = 7\ 5  6.5  6.1  4.7  4.1  Wade's Bog  11. 5  11.2  9.5  7.6  4.7  Ogg's Bog  14. 4  13. 5  11.1  7.7  4.5  Blackwall  15.6  15.2  12 .1  8.8  4.6  Meadow  the t o t a l "number of s p e c i e s v s . a r e a ( C a i n 1 9 3 8 ; Kershaw 1 9 6 4 ) ; I have chosen t o p l o t average number o f s p e c i e s vs. a r e a as a more a c c u r a t e i n d i c a t i o n o f t h e c o m p a r a t i v e community taxonomic diversity.  Fig.  1. M o d i f i e d s p e c i e s - a r e a  curves.  10 C.  D e s c r i p t i o n o f communities.  S a l t marsh  The  f l o r a of the marsh i s s m a l l (18 s p e c i e s ) but v a s c u l a r  p l a n t c o v e r averages the p r e s e n t  about 8 8%.  The v e g e t a t i o n i s dominated ( i n  d i s c u s s i o n , importance v a l u e i s t a k e n t o be a  measure o f dominance) by g r a s s e s and g r a s s - l i k e herbs & 3 ) . The dominant s p e c i e s i n t h e s a l t marsh i s Desoh  amp si a  ( F i g . 4) , which has the h i g h e s t average c o v e r o f any  oespitosa  s p e c i e s , 28.1% (Table 3 ) . Trigloohin species  i s the  maritimum  commonest  (100% frequency) but w i t h an average c o v e r o f 6.8% i s  not as c o n c e n t r a t e d as Desohampsia. Festuoa  (Figs. 2  rubra  maritima,  var.  Juncus  littoralis,  balticus,  Sub-dominant s p e c i e s Salioornia  Carex  lyngbyei,  virginioa and  are  3  Plantago  Glaux  maritima  (Table 3 ) .  TABLE 3. F r e q u e n c y , mean c o v e r , and importance v a l u e s o f the v a s c u l a r p l a n t s p e c i e s o f the S a l t 2 M a r s h . The v a l u e s were c a l c u l a t e d from d a £ a from 1 m q u a d r a t s ; v a l u e s for the 0.25 and 0.01 m quadrats were a l s o c a l c u l a t e d but are not g i v e n here s i n c e t h e y agree w e l l w i t h t h e f i g u r e s below.  Species (acronym)  Desohampsia  (DCS)  oespitosa  F e s t u o a r u b r a (FRU) Trigloohin maritimum  (TMA)  Frequency (%)  Mean c o v e r (%)  Importance v a l u e (I.V.)  85.7  28.1  38.6  70.0 100.0  19.2 6.8  24.5 21.0  11 TABLE 3. (Continued)  Frequency (%)  Species (acronym)  Mean c o v e r (%)  Importance v a l u e (I.V.)  67. 1  11. 7  17 . 8  P l a n t a g o m a r i t i m a (PMA) J u n c u s b a l t i c u s (JBA) Carex lyngby.ei..(CLY) Glaux m a r i t i m a (GMA) Pot e n t i l l a p a c i f i c a (PPA) A g v o s t i s e x a r a t a (AEX) S t e l l a r i a h u m i f u s a (SHU) T r i f o l i u m wormskj o l d i i  61. 4 50. 0 74. 3 62. 8 27 . 1 24. 3 38. 6 15. 7  12. 6 17 . 9 5. 3 7. 8 11. 9 14. 3 2. 0 8. 3  16. 9 16. 8 14. 3 13. 9 7. 2 7. 1 6 .0 3.5  S c i r p u s o e r n u u s (SCE) P u e o i n e l l i a p u m i l a (PPU) Spergularia canadensis  24 . 3 18 . 6 14. 3  0. 5 1. 2 0. 7  3. 3 2. 7 2. 0  D i s t i e h l i s s p i o a t a (DSP) Hordeum b r a c h y a n t h e r u m  10. 0 7. 1  4. 6 10. 7  1. 8 1. 8  2. 8  0. 7  0. 4  Salicornia  (SPA)  virginica  (TWO)  (SCA)  (HBR)  Lilaeopsis  occidentalis  (LOC)  T o t a l p l a n t c o v e r : 88.3%  I know of no such d e s c r i p t i o n o f s a l t marsh v e g e t a t i o n o f the n o r t h P a c i f i c N o r t h American c o a s t .  Chapman (19 60) and  MacDonald (1969) g i v e c u r s o r y r e v i e w s o f w e s t e r n N o r t h American s a l t marshes.  Hanson (19 61) has d e s c r i b e d s a l t marsh v e g e t a t i o n  a l o n g the c o a s t o f w e s t e r n A l a s k a ; C a l d e r and T a y l o r (19 68) g i v e s p e c i e s l i s t s and v e g e t a t i o n notes f o r the s a l t marshes o f the Queen C h a r l o t t e I s l a n d s . Johannessen  ( 1 9 6 1 , 1964) and  F r a n k l i n and Dyrness (1969) l i s t key s p e c i e s and g i v e b r i e f e c o l o g i c a l resume's o f s a l t marshes i n Washington and Oregon.  12  cu  Fig.  2. S a l t M a r s h , mid-May, 1971.  Fig.  3. T i p of S a l t M a r s h , e a r l y May, 1971, from 20 m up a S i t k a s p r u c e . L i g h t - c o l o r e d t u f t s to the b l e a c h e d l o g are o f Desohampsia masses are o f Junaus  oespitosa;  virginioa  of  the  d a r k green  b a l t i c u s . A l o n g the margins o f  mud f l a t s are c i r c u l a r clumps o f Puooinellia Salioornia  left  3  and  Trigloohin  pumila  maritimum.  the 3  13a/  Fig.  4. Desohampsia  oespitosa,  dominant  species of the  Salt  Marsh.  Fig.  5. View f r o m i n t e r i o r o f Wade's Bog, e a r l y Stunted t r e e s  a r e m o s t l y Pinus  oontovta;  sedge l e a v e s b e l o n g m a i n l y t o Cavex  May,  1971.  light-colored obnupta.  14 C a l i f o r n i a ' s s a l t marshes have been more i n t e n s i v e l y s t u d i e d , most n o t a b l y by P u r e r ( 1 9 4 2 ) , Hinde ( 1 9 5 4 ) , V o g l ( 1 9 6 6 ) , and Barbour and D a v i s ( 1 9 7 0 ) . By  i n t e r p o l a t i o n , t h e T o f i n o marsh seems s i m i l a r t o  other  h i g h s a l i n i t y s a l t marshes a l o n g t h e n o r t h P a c i f i c c o a s t o f N o r t h A m e r i c a . U n l i k e s a l t marshes o f e a s t e r n N o r t h America and t h e s o u t h e r n C a l i f o r n i a c o a s t , t h e r e i s no Spartina the lowermost zone o f v e g e t a t i o n .  here t o form  In the T o f i n o a r e a ,  Cavex  i s the commonest s p e c i e s at t h e lowermost l e v e l s ,  lyngbyei  e s p e c i a l l y a l o n g the banks o f d r a i n a g e c h a n n e l s . A t t h e mud f l a t margins o f t h e marsh, Salicornia and Puccinellia  maritimum,  virginica, form l a r g e , more o r  pumila  c i r c u l a r clumps 0.3 t o 3.0 m i n d i a m e t e r Johannessen  Triglochin less  ( F i g u r e 3D.''  (19 64) m a i n t a i n s t h a t such clumps i n d i c a t e t h a t  the  marsh i s expanding r a p i d l y .  Sphagnum bogs  B o t h bogs a r e , f o r t h e most p a r t , dominated by the same s p e c i e s , but t o v a r y i n g degrees ( c f . T a b l e s 4 and 5 ) .  In  g e n e r a l , the v e g e t a t i o n o f Ogg's Bog has a h i g h e r p r o p o r t i o n o f woody s p e c i e s than Wade's Bog (45% v s . 28%). Most n o t i c e a b l e t h e i n c r e a s e d dominances o f Myrica Thuja  plicata  and Gaultheria  (16.2  shallon  p l a n t c o v e r i s about  vs.  3.4),  gale  Linnaea  (3.3 v s . 0.2) 5 3%  ( I . V . o f 36.1 v s . (4.0  borealis  4.9), 1.2),  i n Ogg's Bog. V a s c u l a r  i n Ogg's Bog and 6 3%  i n Wade's Bog.  Bryophyte ground c o v e r , due p r i m a r i l y to Sphagnum 70%  vs.  are  s p p . , i s 60-  and f a i r l y c o n t i n u o u s i n b o t h b o g s , so t h a t t o t a l  plant  15 TABLE 4. F r e q u e n c y , mean c o v e r , and importance v a l u e s o f v a s c u l a r p l a n t s p e c i e s o f Wade's Bog.  Species (acronym)  Frequency (%)  C a r e x p l u r i f l o r a (CPL) A p a r g i d i u m b o r e a l e (ABO) Agrostis aequivalvis (AAE) C a r e x o b n u p t a (GOB) Sanguisorba officinalis (SMI) K a l m i a p o l i f o l i a (KPO) V a c c i n i u m o x y c o c c u s (VOX) C a r e x c a n e s c e n s (CCA) Drosera rotundifolia (DRO) Ledum g r o e n l a n d i c u m (LGR) T r i e n t a l i s a r c t i c a (TAR) E m p e t r u m n i g r u m (END M y r i c a g a l e (MGA) T o f i e l d i a g l u t i n o s a (TGL) T h u j a p l i c a t a (TPL) P i n u s c o n t o r t a (PCO) Gentiana douglasiana (GDO) L i n n a e a b o r e a l i s (LBO) Maianthemum d i l a t a t u m (MDI) Rhynchospora a l b a (RAL) Vaccinium vitis-idaea (VVI) S c i r p u s c e s p i t o s u s (SCS) J u n c u s s u p i n i f o r m i s (JOR) B l e c h n u m s p i c a n t (BSP) Vaccinium uliginosum (VUL) G a u l t h e r i a s h a l l o n (GSH) G e n t i a n a s c e p t r u m (GSC) C o p t i s a s p l e n i f o l i a (CAS) Total plant  c o v e r : 63.1%  Mean c o v e r (%)  the  Importance v a l u e (I.V.)  96. 0 92. 0 98. 0  14. 3 13. 2 4. 8  30. 1 27 . 2 15 . 9  80 . 0 84. 0  7. 0 5. 9  15 . 9 15 . 1  0 0 0 0  3.6 3.1 10. 1 2. 5  14. 0 13. 3 11. . 9 11. , 2  70. 0 96. 0 26. , 0 28 ., 0 48 ., 0 22., 0 20.. 0 14. . 0  2. 8 0. 4 7. 1 5., 7 0., 5 4., 3 4.. 7 0..1  9.,1 8., 9 5., 2 4., 9 4,. 6 3 .4 . 3 ..2 1,.2  12.. 0 10, .0  1.,1 0,.5  1.. 2 0,. 9  6,. 0 4,. 0  2,. 5 0,.5  0,. 7  2,. 0 2. 0 2.. 0 2. 0  5.. 0 1,. 0 0 .5 0. 5  0. 3 0. 2 0. 2 0. 2  2. 0 2.0 2. 0  0 .3 0. 3 0 .1  0. 2 0. 2 0. 2  98. 98. 48. 88.  0. 4  16 TABLE 5. F r e q u e n c y , mean c o v e r , and importance v a l u e s o f v a s c u l a r p l a n t s p e c i e s o f Ogg's Bog.  Species (acronym)  Frequency (%)  Myvioa g a l e (MGA) Apavgidium b o v e a l e (ABO) T h u j a p l i c a t a (TPL) C a v e x o b n u p t a (COB) C a v e x p l u v i f l o v a (CPL) Agvostis aequivalvis (AAE) Sanguisovba officinalis (SMI) Ledum gvoenlandioum (LGR) Vaooinium o x y o o o o u s (VOX) Droseva v o t u n d i f o l i a (DRO) K a l m i a p o l i f o l i a (KPO) Empetvum n i g v u m (END T v i e n t a l i s a v c t i o a (TAR) C a v e x o a n e s o e n s (CCA) T o f i e l d i a g l u t i n o s a (TGL) L i n n a e a b o v e a l i s (LBO) R h y n o h o s p o v a a l b a (RAL) P l a n t a g o m a c v o o a v p a (PMC) G a u l t h e v i a s h a l l o n (GSH) B l e o h n u m s p i c a n t (BSP) G e n t i a n a s o e p t v u m (GSC) Calamagvostis nutkaensis (CNU) Maianthemum d i l a t a t u m (MDI) S c i v p u s o e s p i t o s u s (SCS) C o p t i s a s p l e n i f o l i a (CAS) C o p t i s t v i f o l i a (CTR) J u n o u s s u p i n i f o v m i s (JOR) Desohampsia oespitosa (DCS) P i n u s o o n t o v t a (PCO) L y c o p o d i u m o l a v a t u m (LCD Gentiana douglasiana (GDO) Vaooinium o v a t u m (VOV) Vaooinium vitis-idaea (VVI) 'Cornusunalasohke.nsis (CUN)  88 . 3 77 . 9 70. 1 76. 6 85. 7 79. 2  Mean c o v e r (%)  the  Importance v a l u e (I.V.)  18. 1 8. 9 8. 6 5. 8 3. 5 3. 5  36. 1 18. 4 16 . 2 13. 7 11. 6 10 . 7  93.  5  1. 6  9. 3  76. 81. 76.  6 8 6  1. 9 1. 2 0. 6  8. 1 7. 5 6.1  57 . 1 37 . 7 74. 0 41. 5 61. 0 45 .,4 23. .4 37. ,7 37 .,7 23. .4 33. . 8 18. . 2  1. 8 4. 1 0. 2 2. ,7 0.,4 1. , 0 5.. 2 1. , 7 0.. 9 1.. 0 0,.4 2. . 3  5.8 5 .5 5 .4 5 .. 0 4 ., 7 4., 0 3 ,.9 3 ,.8 3 .. 3 2. . 6 2 ,. 5 2. . 0  27 ., 3  0,.2  2, . 0  15. .6 14 . 3 16 .9 7. 8 9 .1  1.9 1. 5 0 .7 3. 6 1. 8  1. 6 1. 4 1. 4 1. 1 0. 9  7. 8 6 .5 7. 8  2 .1 1. 3 0. 3  0. 8 0. 6 0. 6  6. 5 5. 2  1. 0 0. 6  0. 6 0 .4  3. 9  1. 5  0. 4  17 TABLE 5. CContinued)  Species (acronym)  Vaccinium  Frequency (%)  uliginosum  (VUL)  Juniperus communis (JCO) Nephrophyllidium cristagalli (FCG) Lycopodium inundatum  (LIN)  Eriophorum  polystachion  (EPO)  Cavex pauciflora (CPA) Lysichitum americanum  (LAM)  Mean c o v e r (%)  Importance v a l u e (I.V.)  3.9  0.9  0. 3  2.6 2.6  3.0 2.0  0. 3 0. 3  2.6  1.1  0. 2  1.3  2.0  0.1  1.3 1.3  2.0 0.3  0.1 0.1  T o t a l p l a n t c o v e r : 5 3.4%  c o v e r exceedstlO0%. E v e r g r e e n shrubs and h a l f - s h r u b s , s p e c i e s and the sphagnum moss g i v e b o t h bogs t h e i r  cyperaceous  characteristic  physiognomy ( F i g . 5 ) . Wade (1965) has p r e v i o u s l y c l a s s i f i e d t h e v e g e t a t i o n o f Wade's Bog. The sampling a r e a i n t h i s study would f a l l w i t h i n the Oxycoccus  - Sphagnum  papillosum  mostly  and Carex  pluriflora  a s s o c i a t i o n s as mapped by Wade (1965, F i g 6 ) . Ogg's Bog c o n t a i n s more o f t h e Myrica  gale  and Vaccinium  vitis-idaea  v a r i a n t s and b o t h sampling a r e a s have v e r y l i t t l e o f Scirpus  - Sphagnum  mendocinum  the  association.  R i g g (1925, 1 9 4 0 ) , Osvald ( 1 9 3 3 ) , Hansen ( 1 9 4 7 ) , and Heusser (1960) have d e s c r i b e d the v e g e t a t i o n and s k e t c h e d h i s t o r y o f a number o f sphagnum bogs o f n o r t h P a c i f i c  the  North  A m e r i c a . A p p l i c a t i o n o f g e n e r a l p r i n c i p l e s o f bog development  18 o u t l i n e d by Gorham (1957) and Heinselman (1963) t o the t i o n s o f the above a u t h o r s and t o my own and Wade's  descrip-  observations  suggests t h a t the two study b o g s , and bogs i n g e n e r a l i n the T o f i n o - U c l u e l e t a r e a , are s u c c e s s i o n a l l y j u v e n i l e . The v e r y s h a l l o w peat depths ( a v e r a g i n g no more t h a n 1 m) support suggestion,  this  as does the y o u t h f u l age o f Wade's B o g , e s t a b l i s h e d  as a p p r o x i m a t e l y 400190 y e a r s by r a d i o c a r b o n d a t i n g (Wade 1965). The bogs p r o b a b l y have been formed by p a l u d i f i c a t i o n (swamping) o f p o o r l y d r a i n e d c o a s t a l f o r e s t ,  r a t h e r t h a n by  g r a d u a l , c e n t r i p e t a l f i l l i n g - i n o f water b o d i e s . Wade (19 65) c o n s i d e r e d the r e c e n t  f o r m a t i o n o f a h i g h e r l i p o f l a n d now  covered by S i t k a spruce  (Piaea  and t h e f o r m a t i o n of  sitchensis)  an u n d e r l y i n g hardpan t o be the l i k e l i e s t b a r r i e r s  to  the  d r a i n a g e o f t h e c o a s t a l t e r r a c e upon w h i c h the bogs are  perched.  S u c c e s s i o n i n t h e bogs appears to be toward development o f a h i g h moor or r a i s e d bog o f sphagnum moss, sedges , and ericaceous  shrubs w i t h f u r t h e r bogaexpansion at t h e expense o f  the s u r r o u n d i n g wet f o r e s t .  Of t h e two b o g s , Wade's Bog seems  t o be more advanced i n t h i s s u c c e s s i o n . The average peat depth in  Wade's Bog i s 1 m (Wade 19 6 5 ) ; i n Ogg's B o g , 0.5 m. Average  t r e e c o v e r i s a l s o l e s s i n Wade's Bog, as are t h e I . V . ' s o f s p e c i e s such as  Linnaea b o v e a l i s C o r n u s  theria  and L y a o p o d i u m  shallon  3  t y p i c a l of forest  a l a v a t u m , w h i c h are  undergrowth t h a n sphagnum bogs.  the d o m i n a t i o n of Ogg's Bog by Myriaa significant,  unalaschkensis  s i n c e Myriaa  gale  3  Gaul-  more  Furthermore,  (Table 5) i s v e r y  grows p o o r l y i n h i g h l y a c i d i c h i g h  moor c o n d i t i o n s ( K r a j i n a , p e r s o n a l c o m m u n i c a t i o n ) .  19 S u b a l p i n e meadow  The  f l o r a of B l a c k w a l l Meadow i s the r i c h e s t o f t h e  c o m m u n i t i e s , w i t h 45 s p e c i e s p r e s e n t  four  i n the sample. The  v e g e t a t i o n i s co-dominated by t h r e e s p e c i e s : Valeriana (I.V.  ensis  latifolius  and Potentilla 6).  of  24.9), F e s t u o a  (21.8).  Erigeron  viridula  ( 2 4 . 3 ) , and  peregrinus.  Anemone  sitchLupinus  occidentalism  are secondary co-dominants  flabellifolia  (Table  At the h e i g h t o f the s h o r t growing s e a s o n , the community  c o n s i s t s : o f -.a,, lushc m i x t u r e „of _ showy-flowered f o r b s c a n d more inconspicuous grasses,  sedges,  and wood rushes  (Figs.  6 S 7).  V e g e t a t i o n c o v e r approximates 93%; t h e bare s o i l a r e a s are due m a i n l y t o t h e a c t i v i t i e s o f a s m a l l pocket gopher t h a t  tunnels  below the snow d u r i n g the w i n t e r , j u s t beneath the s o i l In  c o n t r a s t t o many o t h e r mountainous a r e a s , the  v e g e t a t i o n o f n o r t h P a c i f i c N o r t h A m e r i c a has been  surface.  subalpine  little  s t u d i e d by p l a n t e c o l o g i s t s u n t i l r e c e n t y e a r s . Fonda and B l i s s (1969) and Kuramoto and B l i s s in  (1970) have d e s c r i b e d communities  the s u b a l p i n e o f t h e Olympic Mountains o f Washington. B r i n k  (1959, 1 9 6 4 ) , A r c h e r ( 1 9 6 3 ) , and Brooke,  al. (1970) have  s t u d i e d the s u b a l p i n e v e g e t a t i o n o f the southwestern Coast Range of  B r i t i s h C o l u m b i a . Eady (1971) d i s c u s s e d t h e a l p i n e - s u b a l p i n e  zone o f B i g White M o u n t a i n , i n the Okanagan H i g h l a n d o f  southern  B r i t i s h C o l u m b i a . Douglas (1972) has d e s c r i b e d i n d e t a i l the s u b a l p i n e p l a n t communities o f the w e s t e r n N o r t h C a s c a d e s , Washington. Comparison o f t h e s e s t u d i e s l e a d s me t o c o n c l u d e t h a t the B l a c k w a l l Meadow v e g e t a t i o n most c l o s e l y resembles  the  20 ou  Fig.  6. B l a c k w a l l Meadow, e a r l y A u g u s t , 19 72.  Fig.  7. B l a c k w a l l Meadow, e a r l y A u g u s t , 19 72. I n both  pictures,  t h e w h i t e c o l o r i s p r i m a r i l y due t o i n f l o r e s c e n c e s o f Valeriana Anemone the  Occidentalis  yellow,  l a t i f o l i a  and ^mop-tops" o r seed heads o f  sitchensis  3  to  ; the b l u e , t o L u p i n u s Potentilla  and A r n i c a  flabellifolia  mollis.  3  l a t i f o l i u s ;  Arnica  21 drier V a l e r i a n a  sitchensis - Castilleja  elmeri  a s s o c i a t i o n of  Eady ( 1 9 7 1 ) , w i t h some a f f i n i t i e s to t h e m o i s t e r V. -  Veratrum  viride  association  o f Douglas  mediate c o n d i t i o n . i s t o be e x p e c t e d ,  (1972).  This  sitchensis inter-  s i n c e B l a c k w a l l Meadow i s  s i t u a t e d on t h e g e n t l e west s l o p e of a n o r t h - s o u t h r i d g e a l o n g the p h y s i o g r a p h i c break between the e a s t and west f l a n k s o f t h e Cascade Range i n the Manning Park a r e a .  TABLE 6. F r e q u e n c y , mean c o v e r , and importance v a l u e s o f v a s c u l a r p l a n t s p e c i e s o f B l a c k w a l l Meadow.  Species (acronym)  Frequency (%)  Mean c o v e r <%)  Importance v a l u e (I.V.)  76.0  24.6  24.9  F e s t u c a v i r i d u l a (FVI) 100.0 Lupinus l a t i f o l i u s (LLA) 96.0 E r i g e r o n p e r e g r i n u s (EPE) 86.0 Anemone occidentalis 80.0  16.7 14.6 7.5 8.0  24.3 21.8 12.4 11.9  Valeriana  sitchensis  (VSI)  (AOC)  Potentilla  flabellifolia  90.0  4.8  10.4  Erythronium  grandiflorum  7 0.0  2.0  7.0  scoparium (VSC) 42.0 lanceolata 82.0  9.3 1.5  6.9 6.5  (PFL)  (EGR)  Vaccinium Claytonia  (CLA)  the  A r e n a r i a c a p i l l a r i s (ACA) A n t e n n a r i a l a n a t a (ALA) V e r o n i c a c u s i c k i i (VCU) A g o s e r i s a u r a n t i a c a (AAU) Phleum alpinum (PAL) A r n i c a l a t i f o l i a (ALF) L u z u l a h i t c h c o c k i i (LHI) Thalictrum occidentale  72.0 54.0 54.0 60.0 64.0 50.0 56.0 14.0  2.2 4.8 3.1 1.5 1.0 2.7 1.8 18.6  6.3 6.2 5.3 4.8 4.8 4.7 4.6 3.7  Achillea  millefolium  42.0  1.7  3.5  Trisetum  spicatum  44.0  0.8  3.2  (TOO  (AMI)  (TSP)  22 TABLE 6.  (Continued)  Species (acronym)  Frequency (%)  Mean c o v e r (%>  Importance v a l u e (I.V.)  C a r e x r o s s i i (CRO) E l y m u s g l a u o u s (EGL) Silene parryi (SPA) A r n i c a m o l l i s (AMO) P e n s t e m o n p r o c e r u s (PPR) P o a c u s i c k i i (PEP) Senecio integerrimus  44. 0 10 . 0 28.0 22.0 24. 0 26.0 24. 0  0. 5 17 . 6 1.5 2.8 2.3 1.0 1.4  2.8 2.5 2.2 2.1 2.1 1.9 1.9  E i e r a c i u m g r a c i l e (HGR) Luzula spicata (LSP) Sedum l a n c e o l a t u m (SLA) C a s t i l l e j a m i n i a t a (CMI) Pedicularis bracteosa  20.0 20.0 18. 0 16 . 0 12. 0  1.9 0.4 0. 5 1.1 1.0  1.7 1.4 1.2 1.2 0.9  Phlox diffusa (PDI) P o t e n t i l l a d i v e r si f o l i a  .-8:0 " 8o  3.8 2.4  0.8 0.7  4v0 8.0 6.0  8.5 0. 3 2.0  0.6 0.5 0.5  (SIN)  (PBR)  (PDV)  C a r e x s p e c t a b i l i s (CSP) E p i l o b i u m a l p i n u m (EAL) Delphinium nuttallianum  (DNU)  1  Castilleja  parviflora  6. 0  0.8  0.4  Ranunculus  eschscholtzii  6.0  0.6  0.4  (SPI ) 4.0  4.0  1.3 0.7  0. 3 0.3  J u n c u s d r u m m o n d i i (JDR) Hydrophyllum fendleri  2.0 2.0  3.0 3. 0  0.2 0.2  Senecio  triangularis  2.0  2.0  0.2  deliciosum  2.0  2.0  0.2  wallacei  2.0  0.5  0.1  (CAL)  (RES)  Sibbaldia procumbens Microsteris gracilis  (MGR) (HFE) (STR)  Vaccinium  (VDE)  Selaginella  (SWA)  T o t a l p l a n t c o v e r : 9 3.3%  23 III.  THEORY AND RESULTS  A. Population structure  o f i n d i v i d u a l s p e c i e s : ,D/d i n d e x o f  aggregation.  The d i s t r i b u t i o n o f i n d i v i d u a l s o f the same s p e c i e s i n a p a r t i c u l a r p l a n t community g e n e r a l l y i s non-random or  aggregated  ( G r e i g - S m i t h 1964; Kershaw 1 9 6 4 ) , even i n a p p a r e n t l y homogeneous v e g e t a t i o n . An aggregated  population structure  r e s u l t from e n v i r o n m e n t a l h e t e r o g e n e i t y  can  or mosaicism, i n t e r -  s p e c i f i c i n t e r a c t i o n s , and s p e c i e s morphology  (vegetative  a p o m i x i s o r v i c i n i s m i n seed d i s p e r s a l can l e a d t o clumped d i s t r i b u t i o n s ) . The non-randomness clumped ( " c o n t a g i o u s " ) ("regular")  can t a k e t h e form of a  d i s t r i b u t i o n of i n d i v i d u a l s , or an even  d i s t r i b u t i o n (Kershaw 1 9 6 4 ) .  One measure o f a g g r e g a t i o n  i s the D / d i n d e x o f McGinnies  ( i n C u r t i s and M c i n t o s h 1 9 5 0 ) . I have c a l c u l a t e d t h i s i n d e x f o r each s p e c i e s i n t h e p r e s e n t study from presence-absence f o r 'l-i.^-m- 'and" 0; 9-m segments o f t h e 0.3-m wide b e l t after  data  transects,  t h e method o f Smith and Cottam (1967). The a c t u a l  density  (D) was c a l c u l a t e d by c o n s i d e r i n g each 0.3-m square w i t h i n each 1.5- o r 0.9-m segment t o be a p o t e n t i a l i n d i v i d u a l ; t h u s ,  the  maximum d e n s i t y p o s s i b l e per 1.5-m segment was 5, and p e r 0.9-m segment  3. Frequency v a l u e s were computed as t h e p e r c e n t a g e o f  a l l p o s s i b l e 1.5-  or 0.9-m segments o c c u p i e d by a p a r t i c u l a r  s p e c i e s . The expected d e n s i t y (d) v a l u e s c o u l d t h e n be determined from a b i n o m i a l c u r v e (see G r e i g - S m i t h 1964, T a b l e 6).  The d v a l u e t h u s o b t a i n e d was the d e n s i t y (number o f 0.3-m  q u a d r a t s o c c u p i e d per segment)  24 the  t h a t would be expected i f  p o p u l a t i o n were a random one. U s u a l l y the expected d e n s i t y was l e s s than the a c t u a l d e n s i t y , g i v i n g a D / d v a l u e g r e a t e r than 1 and i n d i c a t i n g a g g r e g a t i o n  (Table 7 ) . The s i z e o f the D / d  v a l u e g i v e s some i n d i c a t i o n o f the t y p e and degree o f aggrega t i o n . A D/d greater than 1 i n d i c a t e s a contagious d i s t r i b u t i o n ; a D / d l e s s t h a n 1 i n d i c a t e s a r e g u l a r d i s t r i b u t i o n . The o n l y s p e c i e s t o show markedly r e g u l a r d i s t r i b u t i o n s segments) were T v i g l o c h i n  mavitimum  and F e s t u o a  (both v i a 0.9-m the  viridula,  commonest s p e c i e s i n t h e s a l t marsh and s u b a l p i n e meadow, r e s p e c t i v e l y . U n f o r t u n a t e l y , t h e r e i s no way t o determine  the  s i g n i f i c a n c e o f the D / d i n d e x ' d e v i a t i o n from u n i t y ( B e a l s 1968). I t has been suggested  ( G r e i g - S m i t h 1964) t h a t  succession  i n v e g e t a t i o n i s accompanied by an i n c r e a s e i n the s i z e o f species aggregations of aggregation.  concomitant w i t h a decrease i n the  intensity  One would e x p e c t , t h e n , e a r l y s u c c e s s i o n a l  v e g e t a t i o n t o be composed o f s p e c i e s w i t h , on t h e  average,  h i g h e r D / d v a l u e s t h a n s p e c i e s o f more advanced s u c c e s s i o n a l o r c l i m a x communities. R e g u l a r d i s t r i b u t i o n s r e f l e c t e d by l o w e r D / d ' s are s u g g e s t i v e o f a n e g a t i v e , p r o b a b l y c o m p e t i t i v e a c t i o n between s p e c i e s , and would be expected i n more  inter-  stable,  c l i m a x communities ( B e a l s 19 6 8 ) . To compare the average degree o f non-randomness  i n the  study communities I have used t h e r a t i o o f t h e sum o f observed d e n s i t i e s t o the sum o f e x p e c t e d d e n s i t i e s  ( i . e . , Ed ,  /_d  ),  as recommended by C u r t i s and M c i n t o s h ( 1 9 5 0 ) . Both o b s e r v e d and expected d e n s i t i e s  are the same as t h o s e used i n the c a l c u l a t i o n  o f the D/d i n d e x . Note t h a t t h i s r a t i o i s weighted i n f a v o r o f  25 the more abundant  s p e c i e s , w h i c h i s an a t t r a c t i v e  R a t i o s f o r b o t h segment presented  feature.  s i z e s f o r a l l f o u r communities  are  i n T a b l e 8.  TABLE 7. D / d i n d e x o f  Species  D/d  Salt Desohampsia oespitosa Festuoa rubra Trigloohin maritimum Salioornia virginioa Plantago maritima Junous baltious Glaux maritima Potentilla paoifioa Agrostis exarata Stellaria humifusa T r i f o l i u m wormskj o l d i i Scirpus cernuus Puooinellia pumila Spergularia canadensis Distiohlis spicata Hordeum braohyantherum Lilaeopsis ocoidentalis  aggregation.  ( 0 . 9 - m segments)  D/d (1.5-m  segments)  Marsh 65 77 11 52 , 03 ,46 ,53 , 07 ,42 ,46 ,83 1.90 1.93 2.26 3.97 3.10 1.88  1.80 1.98 0. 77 1. 87 1. 60 2. 22 1. 93 1. 67 1, 78 1. 86 2. 11 1. 62 1. 55 72 53 08 1.39 mean -  1. 76  .77 - 2.53  mean = 2 range:  1.11 •  g Carex p l u r i f l o r a Apargidium boreale Agrostis aequivalvis Carex obnupta Sanguisorba officinalis Kalmia p o l i f o l i a Vaooinium oxyoooous Carex canesoens Drosera rotundifolia Ledum groenlandioum  1.00 1.29 0.92 1.23 1.13 1.13 0.98 1.47 1.03 1.29  1. 31 1.61 1. 21 1.67 1.53 1.38 1. 24 1.62 1.38 1.74  TABLE 7.  26  (Continued)  Species  D / d (0.9-m segments)  Trientalis arctioa Empetrum nigrum Myrioa gale Tofieldia glutinosa Thuja plicata Pinus eontorta Gentiana douglasiana Linnaea b o r e a l i s Maianthemum d i l a t a t u m Rhynohospora alba Junous supiniformis Coptis trifolia  1 .16 1 .63 1 .67 1 .15 1 . 63 1 . 39 1 .28 1 .96 1 .50 1 . 57 2 . 33 1 .0 0 mean = 1.35 r a n g e : 0. 92 - 2.33  D/d (1.5-m segments)  1 . 53 1 .93 2 .19 1 .29 1 . 81 1 . 82 1 .29 1 . 97 1 .60 2 . 71 2 .67 1 .11 mean = 1 r a n g e : 1. 11  Ogg's Bog Myrioa gale Apargidium boreale Thuja p l i o a t a Carex obnupta Carex pluriflora Agrostis aequivalvis Sanguisorba officinalis Ledum groenlandicum Vaooinium oxyoocous Drosera rotundifolia Kalmia polifolia Empetrum nigrum Trientalis arctioa Carex canescens Tofieldia glutinosa Linnaea borealis Rhynohospora alba Plantago macrocarpa Gaultheria shallon Blechnum spioant Gentiana soeptrum Calamagrostis nutkaensis Maianthemum d i l a t a t u m Soirpus cespitosus Coptis asplenifolia Coptis trifolia Junous supiniformis Desohampsia oespitosa  0. 96 1. 20 1. 35 1. 50 1. 10 1. ,30 1. 13 1. ,26 1. ,43 1.,38 1.. 27 1.,75 1.,42 1.,41 1.,25 1., 53 2. .02 1..75 1., 3 6 1..37 1,.39 1,.71 1..45 1,. 59 1,. 98 1,.86 2, . 07 1,.33  1. 18 1. 71 1. 81 2. 02 1. 47 1. 62 1. ,47 1. 65 1. , 83 1.,79 1. ,60 2. ,16 2. , 07 1.,69 1.,53 2. ,02 2. .85 2. .14 1.,70 1..60 1..40 2, . 08 1,.77 1,.92 2, .73 2, .07 2, .90 1,. 94  TABLE 7.  27  (Continued)  D/d  Species  (0.9-m segments)  D / d (1.5-m segments)  63 76 13 1. 31 2. 58 1. 94 1.68  1.43 1.79 1.64 1.28 2.04 1.90 1.28  Pinus contorta Lycopodium clavatum Gentiana douglasiana Vaooinium ovatum Vaooinium vitis-idaea Vaooinium uliginosum Juniperus communis  1.50  mean range:  0.9 6 - 2.0 7  mean = 1.88 range:  1.18  - 2.9 0  B l a c k w a l l Meadow Valeriana sitchensis Festuca viridula Lupinus latifolius Erigeron peregrinus Anemone oocidentalis Potentilla flabellifolia Erythronium grandiflorum Vaooinium scoparium Claytonia lanceolata Arenaria oapillaris Antennaria lanata Veronica cusickii Agoseris aurantiaca Phleum alpinum Arnica latifolia Luzula hitchcockii Thalictrum occidentale Achillea millefolium Trisetum spicatum Carex r o s s i i Elymus glaucus Silene parryi Arnica mollis Poa c u s i c k i i Senecio integerrimus Hieracium gracile Luzula spicata Sedum lanceolatum Castilleja miniata Penstemon procerus Pedicularis bracteosa Potentilla diversifolia  1. 80 0. 63 1. 12 1. 03 1. 30 0. 97 1. 19 1. 71 1. 28 1. 55 1. 52 1. 37 1. 06 1..01 1.,30 1.,32 1.,88 1., 35 1..15 1..29 1,.93 1,.23 1..60 1.. 01 1 .30 1..70 1 .16 1 .25 1 .25 1.. 55 1 . 58 1 .40  2. 05 1. 15 1. 36 1. 46 1. 68 1. 37 1. 53 2. 29 1. 82 2. 28 2. 04 1. 86 1. ,16 1. 08 1. , 37 1.,67 2. , 74 1., 68 1., 29 1.,42 3. . 09 1,.25 2, . 53 1,.11 1,. 53 1..96 1 . 24 1 .48 1 .37 2 .07 1 . 52 1 . 53  TABLE 7.  28  (Continued)  Species  D / d (0.9-m segments)  D/d (1.5-m segments)  1.69 1.31 1.62 2.00 1.65 1.90 2.06 1.69  Epilobium alpinum Ranunculus eschscholtsii S i b b a l d i a procumbens Miorosteris gracilis Senecio triangularis Vaccinium deliciosum Selaginella wallacei Veratrum v i r i d e  1.65 1.62 2.08 2.08 2.28 3.07 1.79 2.13  mean = 1.4 2 range:  0.6 3 - 2.0 6  Wade's Bog has the l e a s t aggregated This i s expected,  mean = 1.7 7 range:  vegetation  1.08  - 3.0 9  (Table 8).  s i n c e t h i s bog appears to be n e a r e s t  the  c l i m a x s t a t e f o r t h e c o a s t a l sphagnum bog community t y p e . A t t h e o t h e r extreme, t h e S a l t Marsh has by f a r t h e h i g h e s t D/d  average  v a l u e . Perhaps t h i s i s because t h e r i g o r o u s p h y s i c a l  environment of the s a l t marsh imposes f a i r l y d i s c r e t e z o n a t i o n (promoting a g g r e g a t i o n )  habitat  and p l a c e s a premium on mere  s u r v i v a l , diminishing i n t e r s p e c i f i c competitive e s p e c i a l l y i n the p i o n e e r mud f l a t v e g e t a t i o n  effects,  ( c f . C l a r k e and  Hannon 1970, 1 9 7 1 ) . I t c o u l d a l s o be due i n p a r t t o  the  morphology o f the marsh s p e c i e s , many o f which have  extensive  vegetative  spread.  Ogg's Bog has r e l a t i v e l y s t r o n g l y  aggregated  v e g e t a t i o n , w h i l e t h a t o f B l a c k w a l l Meadow i s o n l y weakly aggregated.  Both communities have d i v e r s e , m o s a i c - l i k e m i c r o -  topographies.  The f a c t t h a t Ogg's Bog has a h i g h e r average D/d  29 degree  t h a n B l a c k w a l l Meadow r e f l e c t s , I t h i n k , a much h i g h e r  o f i n t e r s p e c i f i c c o m p e t i t i o n i n the s u b a l p i n e meadow (see I I I - B ) and p r o b a b l e advanced  successional'status.  TABLE 8. Weighted average community D/d v a l u e s .  0.9-m segments, ratio =  Site  S a l t Marsh Wade's Bog Ogg's Bog B l a c k w a l l Meadow  Sect.  a  1.5-m segments, ratio =  1.39 1.12 1.25 1.14  1.97 1.44 1.69 1.53  A s i m p l e , unweighted average was a l s o computed f o r each community, and t h e r e s u l t s were e q u i v a l e n t . However, i n a l l cases the weighted average was l e s s than t h e u n w e i g h t e d , i n d i c a t i n g t h a t t h e r a r e r s p e c i e s had h i g h e r D / d ' s (were more a g g r e g a t e d ) , which seems r e a s o n a b l e .  Closer examination of Table 8 r e v e a l s that a l l four communities e x h i b i t more i n t e n s e a g g r e g a t i o n a t 1.5-m i n t e r v a l s , as would be expected merely from t h e i n c r e a s e i n i n t e r v a l l e n g t h from 0.9 m. However, t h e change i n segment s i z e does not affect  a l l s i t e s e q u a l l y . In p a r t i c u l a r , the s a l t marsh s p e c i e s  show a c o m p a r a t i v e l y g r e a t e r  i n c r e a s e i n a g g r e g a t i o n at the  l e v e l . T h i s may be i n d i c a t i v e o f a secondary s c a l e o f i n the S a l t Marsh. That i s , i n d i v i d u a l s o f the same tend t o o c c u r t o g e t h e r w i t h i n a r a d i u s o f a t l e a s t  1.5-m  pattern  species 0.9 m i n a l l  c o m m u n i t i e s ; i n Ogg's Bog and t h e s u b a l p i n e meadow, and e s p e c i a l l y i n t h e s a l t marsh, t h e r e i s a tendency f o r  the  30 i n d i v i d u a l s to form l a r g e r clumps. T h i s i s i n agreement w i t h Brereton's  (19 71) f i n d i n g s t h a t , a t l e a s t  i n s a l t marsh  s u c c e s s i o n , s p e c i e s are i n i t i a l l y randomly d i s t r i b u t e d l a t e r become more aggregated  and e v e n t u a l l y the  but  aggregations  increase i n s i z e .  B. I n t e r s p e c i f i c  relationships.  Association  I n t e r s p e c i f i c a s s o c i a t i o n can be d e t e c t e d  by c o n s t r u c t i o n 2  of a 2x2 c o n t i n g e n c y t a b l e and c a l c u l a t i o n of x  values  based  on j o i n t o c c u r r e n c e o f p a r t i c u l a r s p e c i e s p a i r s i n sample q u a d r a t s (Kershaw 1 9 6 4 ) . T h i s has been done f o r a l l p o s s i b l e s p e c i e s p a i r s i n each community, p r o v i d e d each s p e c i e s  occurred 2 i n at l e a s t f i v e sampling u n i t s (see Appendix 2 ) . The x v a l u e shows whether t h e d i f f e r e n c e between t h e observed and expected number o f q u a d r a t s o f c o - o c c u r r e n c e i s s i g n i f i c a n t o r n o t . The 2 s i g n o f the x p o s i t i v e or  v a l u e i n d i c a t e s whether t h e a s s o c i a t i o n  is  negative.  2 Since c a l c u l a t i o n of x based on q u a l i t a t i v e p r e s e n c e / absence d a t a , the t y p e and l e v e l o f a s s o c i a t i o n i s dependent on 2 ± s  quadrat s i z e ( G r e i g - S m i t h 1964; Kershaw 19 6 4 ) . T h e r e f o r e x v a l u e s have been c a l c u l a t e d f o r f i v e d i f f e r e n t  quadrat  sizes  t h e t h r e e random quadrat s i z e s and t h e 1.5- and 0.9-m t r a n s e c t segments.  I t i s hoped t h a t t h i s approach w i l l  more  v a l i d l y d e t e c t t r e n d s o f a s s o c i a t i o n and i n d i c a t e s c a l e s o f pattern  i n the communities.  31 2 I n most c a s e s , the r e s u l t s o f the x t e s t s are  consistent  throughout the d i f f e r e n t quadrat s i z e s . O c c a s i o n a l changes i n s i g n from one quadrat s i z e t o a n o t h e r may be viewed as o f quadrat  effects  s i z e a n d / o r number.  C o l e ' s i n d e x of i n t e r s p e c i f i c a s s o c i a t i o n ( C o l e 1949; H u r l b e r t 19 69) was a l s o determined f o r a l l s p e c i e s p a i r s . C o l e ' s 2 i n d e x g i v e s e s s e n t i a l l y the same i n f o r m a t i o n as a x v a l u e but reduces the v a l u e s t o a range from +1 t o - 1 . These r e s u l t s are a l s o p r e s e n t e d i n Appendix 2. A s s o c i a t i o n as a s t a t i s t i c can suggest p o s s i b l e causes o f species'  d i s t r i b u t i o n a l patterns.  Highly negative associations  may i n d i c a t e d i s s i m i l a r h a b i t a t r e q u i r e m e n t s o r c o m p e t i t i v e e x c l u s i o n o r a l l e l o p a t h y . H i g h l y p o s i t i v e a s s o c i a t i o n s may i n d i c a t e s i m i l a r h a b i t a t r e q u i r e m e n t s , absence of s t r o n g c o m p e t i t i o n , o r e n v i r o n m e n t a l m o d i f i c a t i o n by one s p e c i e s  to  the advantage o f a n o t h e r (Kershaw 1964; Smith and Cottam 1967; G o o d a l l 1 9 7 0 ) . Byer (1970) m a i n t a i n s t h a t s t r o n g p o s i t i v e and n e g a t i v e a s s o c i a t i o n i s c h a r a c t e r i s t i c o f the v e g e t a t i o n o f heterogene'ous  habitats,  and o f extreme h a b i t a t s  e n v i r o n m e n t a l d i f f e r e n c e s may be c r i t i c a l . been suggested  i n which s m a l l  Furthermore, i t  has  ( G r e i g - S m i t h 1964; Kershaw 1964) t h a t s u c c e s s i o n  i s accompanied by a decrease i n i n t e r a c t i o n between s p e c i e s . 2 t h i s s h o u l d be r e f l e c t e d i n l e s s h e t e r o g e n e i t y of x more s t a b l e o r s u c c e s s i o n a l l y advanced v e g e t a t i o n converse s h o u l d a l s o h o l d .  values i n the  32  A s s o c i a t i o n - S a l t Marsh  I n t e r s p e c i f i c a s s o c i a t i o n i n the s a l t marsh i s marked, as can  be seen i n Appendix 2 and F i g . 8. F i g . 8 i l l u s t r a t e s , the  two main s p e c i e s g r o u p i n g s . The a g g r e g a t i o n dominated by Deschampsia  Glaux of  cespitosa, Festuca  rubra,  Juncus  o c c u r s on the h i g h e r , d e n s e l y v e g e t a t e d  maritima  the marsh, whereas the group dominated by  virginica  3  and  balticus,  Carex  lyngbyei,  and P l a n t a g o  maritima  levels  Salicornia i s more  c h a r a c t e r i s t i c o f t h e l o w e r l e v e l mud f l a t s .  Desohampsia,  Carex,  and  cernuus of  Plantago,  Salicornia,  Stellaria  humifusa,  Scirpus  e x h i b i t moderate p o s i t i v e a s s o c i a t i o n w i t h some  b o t h g r o u p i n g s . Triglochin  maritimum  i s a more o r  species  less  u b i q u i t o u s s p e c i e s i n t h i s marsh, o c c u r r i n g so f r e q u e n t l y as fall  i n neither  to  grouping.  There are o c c a s i o n a l i n c o n s i s t e n c i e s i n t h e r e s u l t s o f the 2 X  t e s t s . For example, i n the s p e c i e s p a i r Carex  Plantago  lyngbyei*  m a r i t i m a , s t r o n g p o s i t i v e a s s o c i a t i o n i s i n d i c a t e d by  quadrat s i z e s l x l , 0 . 5 x 0 . 5 , and 1.5x0.3 m (Appendix 2 ) . A t t h e l e v e l o f the 0 . 3 x 0 . 3 m q u a d r a t s ,  however, s t r o n g  negative  a s s o c i a t i o n i s i n d i c a t e d . Perhaps t h i s i s i n d i c a t i v e o f c o m p e t i t i o n t h a t was masked i n the l a r g e r quadrats but showed up i n t h e s m a l l e r q u a d r a t . I n c o n t r a s t , Scirpus lxl  cernuus  the p a i r Juncus  balticus  e x h i b i t s s i g n i f i c a n t negative a s s o c i a t i o n v i a  m and 0 . 5 x 0 . 5 m quadrats but s t r o n g p o s i t i v e a s s o c i a t i o n v i a  0 . 3 x 0 . 3 m q u a d r a t s (Appendix 2 ) . I n t h i s c a s e , the l a r g e number of  co-occurrences  i n the 0 . 3 x 0 . 3 m q u a d r a t s may have been  required t o manifest  a positive association only mildly  33<v  Fig.  8. S a l t Marsh s p e c i e s  constellation.  The e l l i p s e s  shaded r o u g h l y p r o p o r t i o n a l t o t h e s p e c i e s v a l u e . Each l i n e r e p r e s e n t s a l e v e l o f positive association.  That i s t o  are  importance  significant  say:  t h e r e are t h r e e l i n e s i f , f o r one quadrat  size,  P = 0 . 0 0 5 ; two l i n e s i f P = 0 . 0 1 ; one l i n e i f P = 0.05. S i n c e t h e r e are f i v e d i f f e r e n t  quadrat s i z e s  (three  random q u a d r a t s p l u s two t r a n s e c t segments), 15 l i n e s are the maximum p o s s i b l e . The diagram does not i n d i c a t e negative  association.  AEX  -  Agrostis  CLY  -  Carex  DCS DSP FRU GMA HBR JBA LOC  -  Desohampsia cespitosa Distichlis spicata Festuca rubra Glaux maritima Hordeum braohgantherum Juncus balticus Lilaeopsis occidentalis  exarata lyngbyei  PMA PPA PPU SCA SCE SHU SPA TMA TWO -  Plantago maritima Potentilla pacifica Puccinellia pumila Spergularia canadensis Scirpus cernuus Stellaria humifusa Salicornia virginica Trigloohin maritimum Trifolium wormskjoldii  34 i n d i c a t e d a t the 1.5x0.3 m l e v e l and missed e n t i r e l y by the random q u a d r a t s .  A s s o c i a t i o n - Sphagnum bogs  As was p o i n t e d out e a r l i e r i n S e c t . I I - C , the two sphagnum bogs are q u i t e s i m i l a r i n f l o r a and v e g e t a t i o n . T h i s is  borne out i n F i g s .  9 and 10. Both bogs are dominated by a  f a i r l y large c o n s t e l l a t i o n of species that includes pluriflora,  C. o b n u p t a ,  Agrostis  aequivalvis,  Drosera  rotundifolia,  Apargidium. boreale, Kalmia  polifolia,  Trientalis  Ledum  b o t h the  Oxyoooous  - Sphagnum  papillosum  oxyoooous,  groenlandioum  and  arctioa,  Cavex  Vaooinium  3  Tofieldia  as i m p o r t a n t s p e c i e s . T h i s a g g r e g a t i o n  glutinosa  similarity  incorporates  and Ledum  -  Sphagnum  a s s o c i a t i o n s o f Wade ( 1 9 6 5 ) .  capillaoeum  Ogg's Bog i n c l u d e s more o f the s p e c i e s group dominated by Thuja  plicata  3  Empetrum  nigrum,  and  Linnaea  borealis  t h a n does  Wade's Bog. T h i s i s an a s s o c i a t i o n o f h i g h , f a i r l y dry hummocks and c o n t a i n s bog f o r e s t contorta,  Maianthemum d i l a t a t u m ,  and Gaultheria  spicant,  elements such as Thuja,  shallon.  Coptis  Linnaea,  Pinus  asplenifolia,  Blechnum  Ogg's Bog a l s o c o n t a i n s two  a s s o c i a t i o n s t h a t are unimportant i n the sample area o f Wade's Bog. in  Myrioa  gale  dominates a shrubby a s s o c i a t i o n o f l a r g e  Ogg's Bog. A l t h o u g h i t i s a n i t r o g e n - f i x i n g s p e c i e s  1951,  1967; R o d r i g u e z - B a r r u e c a 19 6 8 ) , Myrioa  extent  (Bond  grows so d e n s e l y  as t o have n e g a t i v e o r weakly p o s i t i v e a s s o c i a t i o n s w i t h most of  t h e o t h e r bog s p e c i e s  (see Appendix 2 ) . Another group o f  s p e c i e s t h a t i s f a i r l y common i n Ogg's Bog i s dominated by  3 5 o-  F i g . .9. Wade's Bog,  species  constellation.  AAE ABO CCA COB CPL DRO ENI GDO KPO LGR LBO MDI MGA  -  P C O - Pinus  RAL SMI TPL TGL TAR  -  VOX -  [CPU  Agrostis aequivalvis Apargidium boreale Carex canescens Carex obnupta Carex pluriflora Drosera rotundifolia Empetrum nigrum Gentiana douglasiana Kalmia polifolia Ledum groenlandicum Linnaea borealis V aianthemum dilatatum V y r i c a gale contorta  Rhynchospora alba Sanguisorba officinali Thuja plicata Tofieldia glutinosa Trientalis arctica teccinium  oxycoccus  KPO  k  LGR  GDO  PCO  COB SMI CCA  3 6 ox  Fig.  10.  O g g s Bog, 1  species  constellation.  3U  37 Carex  oanescens  Gentiana  Plantago  3  sceptrum,  Juncus  macrocarpa, s u p i n i f ormis,  Rhyncho spora and  Scirpus  and grows i n a r e a s o f s h a l l o w peat t h a t are under water f o r much o f the As  suggested  alba, cespitosus  standing  year.  i n S e c t . I I - C , Ogg's Bog i s p r o b a b l y i n an  e a r l i e r stage o f s u c c e s s i o n t h a n Wade's Bog. P e r u s a l o f Appendix 2 and F i g s .  9 and 10 i n d i c a t e s t h a t Ogg's Bog i s much  more heterogeneous i n i n t e r s p e c i f i c a s s o c i a t i o n than i s Wade's 2 Bog; i . e . , t h e r e a r e more s i g n i f i c a n t x v a l u e s ( b o t h p o s i t i v e and n e g a t i v e ) 2 of  these x '  s  per s p e c i e s and a h i g h e r average a b s o l u t e  i - Ogg's Bog t h a n i n Wade's Bog (Table 9 ) . The n  greater heterogeneity reflects  value  (and a l s o t h e g r e a t e r number of  species)  the g r e a t e r v a r i e t y o f m i c r o h a b i t a t s a v a i l a b l e i n  Ogg's B o g , and a l s o a f f i r m s the s u g g e s t i o n of G r e i g - S m i t h (19  64)  and Kershaw (1964) t h a t s u c c e s s i o n i s accompanied by a d e c r e a s e in  species  interactions. A s s o c i a t i o n - S u b a l p i n e meadow  There i s a l s o s t r o n g i n t e r s p e c i f i c a s s o c i a t i o n i n B l a c k w a l l Meadow (Appendix 2 , F i g . 1 1 ) . Four main s p e c i e s g r o u p i n g s are apparent ( F i g . 1 1 ) . There i s a l a r g e number o f s p e c i e s o f low importance t h a t t e n d t o o c c u r on d r y m i c r o s i t e s w i t h i n t h e meadow, g e n e r a l l y where t h e s o i l i s s h a l l o w and/or v e r y w e l l d r a i n e d . T h i s a g g r e g a t i o n i s dominated by lanata  and A r e n a r i a  integerrimus, lanceolatum,  capillaris.  Agoseris Arnica  Penstemon  aurantiaca,  m o l l i s , and  procerus,  Antennaria Senecio  Achillea millefolium,  Castillega miniata  Seolum  are i m p o r t a n t  3 8 cu  F i g . 11.  B l a c k w a l l Meadow, species  constellation.  39 forbs,  Toa  and Carex  3  Luzula  spicata  Trisetum  and  spicatum,  association.  the study meadow t h e few s o i l p o c k e t s t h a t remain m o i s t  throughout  the growing season support  p l a n t s dominated by T h a l i c t r u m  Other s p e c i e s Senecio  3  important graminoids i n t h i s  cusiekii In  rossii  frequenting  triangularis  3  a lush association of  o c c i d e n t a l e and Elymus  these moist s i t e s  Ranunculus  glauous.  are Veratrum  e s c h s c h o l t z i i and  viride  3  Epilobium  3  alpinum.  The meadow v e g e t a t i o n  i s dominated by s p e c i e s  more o r l e s s mesic h a b i t a t s . Festuca  viriduta  and Veronica  The a s s o c i a t i o n dominated by  Erigeron peregrinus  3  cusiekii  3  Erythronium  Lupinus  3  and P o t e n t i l t a f l a b e l l i f o l i a  Occidentalis  3  the o t h e r hand, t o f a v o r m o i s t - m e s i c h a b i t a t s , Vaccinium  of  and E i e r a c i u m  gracile  p o s i t i v e a s s o c i a t i o n to d r y - s i t e In  in  scoparium  grandiflorum,  appears t o o c c u r on the d r y - m e s i c  The group dominated by V a l e r i a n a s i t c h e n s i s Anemone  growing i n  sites.  latifolius  seems, on  although  form s t r o n g b r i d g e s  species  ( F i g . 11).  an e c o l o g i c a l study o f the a l p i n e l a r c h (.Larix  lyallii)  the-r-Eacif ie:; N o r t h w e s t , Arno and Habeck (1972 ) g i v e a l i s t o f  7 5 i n d i c a t o r s p e c i e s o f the u n d e r s t o r y w i t h a l p i n e l a r c h , w i t h 25 s p e c i e s  vegetation  associated  each as i n d i c a t o r s o f x e r i c ,  m e s i c , and h y d r i c c o n d i t i o n s . The d i s p o s i t i o n o f many o f species  i n F i g . 11 agrees w i t h t h a t p r e s e n t e d  by t h e s e  and my judgements of t h e s o i l m o i s t u r e p r e f e r e n c e s  the  authors,  o f most o f  the more t h a n 2 0 s p e c i e s t h a t B l a c k w a l l Meadow has i n common with their l i s t  o f i n d i c a t o r s agree w i t h t h e i r  An e x t r e m e l y i n t e r e s t i n g meadow i n v o l v e s  Castilleja  assessments.  a s p e c t o f a s s o c i a t i o n i n the  miniata  and P e d i c u l a r i s b r a c t e o s a .  3  both o f which are r o o t h e m i p a r a s i t e s  ( K u i j t 1969).  has v e r y s t r o n g p o s i t i v e a s s o c i a t i o n w i t h Arnica secondarily with L u z u l a  spicata  and P e n s t e m o n  c o - o c c u r s s i g n i f i c a n t l y w i t h Vaccinium  laris Luzula  hitchcockii.  40 Castilleja and  mollis, procerus.  Pedicu-  and  scoparium  These a s s o c i a t i o n phenomena are p r o b a b l y  due i n g r e a t p a r t t o h o s t - p a r a s i t e  co-occurrence.  Correlation  The d e t e c t i o n of a s s o c i a t i o n i s based on the mere or  absence o f s p e c i e s . The q u a n t i t a t i v e  relationships  presence between  s p e c i e s are b e s t d e t e c t e d by a c o r r e l a t i o n c o e f f i c i e n t ,  rather  t h a n s a measure o f a s s o c i a t i o n . For each p o s s i b l e v a r i a b l e p a i r of  s p e c i e s I have c a l c u l a t e d an r , or product-moment  coefficient  correlation  o f c o v e r v a l u e s , i n the manner o f S o k a l and R o h l f  (1969). A t - t e s t  ( S o k a l and R o h l f 1969) of the s i g n i f i c a n c e o f  each r was a l s o computed (Appendix 2 ) . N o r m a l i t y i s an assumption o f r. T h e r e f o r e at l e a s t  five  c o i n c i d e n t presences are r e q u i r e d f o r t h e c a l c u l a t i o n o f the coefficient,  so as to a v o i d exceeding the l i m i t s o f d e v i a t i o n  from n o r m a l i t y set by S o k a l and Sneath (19 6 3 ) . Trends i n c o r r e l a t i o n depend on the sample quadrat s i z e ( G r e i g - S m i t h 1964; Kershaw 19 64) and changes r e l a t e d t o v a r i a t i o n i n quadrat can  size  y i e l d i n f o r m a t i o n about the n a t u r e and causes o f i n t e r s p e c i f i c  association. The causes o f c o r r e l a t i o n are e s s e n t i a l l y the same as t h o s e o f a s s o c i a t i o n . However, t h e s e c a u s a l f a c t o r s  do not  n e c e s s a r i l y make s i m i l a r c o n t r i b u t i o n s t o a s s o c i a t i o n and correlation.  41 C o r r e l a t i o n - S a l t Marsh  The  most abundant  s p e c i e s o f t h e h i g h marsh had p r e -  d o m i n a n t l y n e g a t i v e c o r r e l a t i o n s w i t h o t h e r s p e c i e s , but  the  dominant s p e c i e s o f the low marsh had about t h e same number o f t o t a l p o s i t i v e and n e g a t i v e c o r r e l a t i o n s . T h i s suggests b o t h t h a t t h e r e i s more i n t e n s e c o m p e t i t i o n i n the more o r l e s s c o n t i n u o u s l y v e g e t a t e d h i g h marsh meadow, and t h a t , i n the more extreme c o n d i t i o n s o f the low l e v e l mud f l a t s , s p e c i e s such as Salicornia  may  virginica  Plantago  3  maritima,  and  Carex  lyngbyei  p o s i t i v e l y i n f l u e n c e the e s t a b l i s h m e n t and s u r v i v a l o f  other pioneer species. 2 In g e n e r a l , v a l u e s of x and C o l e ' s c o e f f i c i e n t o f a s s o c i a t i o n agree w i t h the r v a l u e s o v e r t h e whole community, 2 c o r r e l a t i o n s between r ' s  and x ' s are s i g n i f i c a n t l y p o s i t i v e  (P<0.01) f o r most quadrat s i z e s . D i s p a r i t i e s do o c c u r , however. For  example, the s p e c i e s p a i r s Triglochin  balticus  s  Agrostis  Festuca exarata,  rubra^Agrostis and G l a u x  Festuca  rubra  Juncus  maritima^Stellaria  have s i g n i f i c a n t l y p o s i t i v e x r's.  exarata,  maritimum*Juncus balticus* humifusa  v a l u e s but s i g n i f i c a n t l y  negative  i s a p a r t i c u l a r l y " i n s t r u c t i v e s p e c i e s -in " t h i s  r e g a r d . A t almost a l l quadrat s i z e s , i t c o - o c c u r s with D e s c h a m p s i a  all  cespitosa  3  Juncus  balticus  3  significantly  Potentilla pacifica  and  Agrostis  all  o f t h e s e s p e c i e s , and the c o r r e l a t i o n s become i n c r e a s i n g l y  exarata  3  y e t has s t r o n g n e g a t i v e c o r r e l a t i o n s w i t h  n e g a t i v e w i t h d e c r e a s i n g quadrat s i z e . E v i d e n t l y , a l t h o u g h these species co-occur s i g n i f i c a n t l y , the r e s u l t a n t i n t e r a c t i o n s lead to negative c o r r e l a t i o n s .  competitive  3  42 C o n v e r s e l y , t h e s p e c i e s p a i r s Triglochin Spergularia  canadensis  and C a r e x  lyngby  maritimumx  eixTrifolium  wormsk-  2 have s i g n i f i c a n t l y n e g a t i v e x  joldii  positive r ' s .  v a l u e s but  I n t h e s e c a s e s , the s p e c i e s do not  c o - o c c u r , but when t h e y do t h e y perform w e l l Spergularia w h i l e Triglochin  frequently  together.  i s almost e x c l u s i v e l y a mud f l a t  canadensis maritimum  marsh and o c c u r s throughout the mud f l a t s ,  significantly  species,  i s the commonest s p e c i e s i n the i t . When Triglochin  does grow on  i t i s o f t e n accompanied by Spergularia,  perhaps  because the l o c a l t i d a l seed d i s p e r s a l o f the annual ( S a l i s b u r y 19 58) t e n d s t o c o n c e n t r a t e  i t s subsequent  Spergularia establish-  ment around clumps o f e x i s t i n g v e g e t a t i o n such as The c a s e of  difficult  Carex  lyngbyeixTrifolium  wormskjoldii  Triglochin. i s more  t o e x p l a i n . The n e g a t i v e a s s o c i a t i o n cum p o s i t i v e  c o r r e l a t i o n may be due t o n i c h e d i s s i m i l a r i t y  (see S e c t . I I - H )  combined w i t h a s t i m u l a t i o n o f the performance o f Carex by  the n i t r o g e n f i x a t i o n o f Trifolium A f i n a l point of interest  lyngbyei  wormskjoldii.  i s t h a t Distichlis  is  spicata  the o n l y s p e c i e s t o have a p o s i t i v e c o r r e l a t i o n w i t h bare mud. A c c o r d i n g t o Adams ( 1 9 6 3 ) , V o g l ( 1 9 6 6 ) , and R e d f i e l d Distichlis  i s a s p e c i e s o f h i g h e r marsh l e v e l s ' a l o n g t h e  A t l a n t i c and C a l i f o r n i a n c o a s t s . in  (1972),  Both i n t h e study marsh and  o t h e r s a l t marshes i n t h e v i c i n i t y , I have observed  t o be an i n f r e q u e n t  Distichlis  s p e c i e s t h a t when p r e s e n t u s u a l l y grows a t  t h e v e g e t a t i o n margins on low mud f l a t s . P e r h a p s , s i n c e D. spicata area,  i s near t h e nor.thern l i m i t o f i t s range i n the i t o c c u r s on what would n o r m a l l y be u n u s u a l s i t e s  S t e b b i n s and Major 1 9 6 5 ) .  Tofino (cf.  43 C o r r e l a t i o n - Sphagnum bogs  S p e c i e s p a t t e r n s o f c o r r e l a t i o n w i t h i n each bog are unpredictable. in  Some s p e c i e s p a i r s e x h i b i t the same c o r r e l a t i o n  both bogs; e g . ,  Vaccinium  oxy.coccus  Carex  o b n u p t a x Ledum  *Drosera  t  x  x-Sanguisorba  have p o s i t i v e  rotundifolia  kiid2Ap argidium.. d:o reaXexLe.dum..  groenlandicum  !  have n e g a t i v e r ' s  officinalis  and  groenlandicum  r's  and A p a r g i d i u m  i n b o t h Wade's Bog  and Ogg's Bog. Other s p e c i e s p a i r s change; e g . , r f o r obnupta*Sanguis positive,  and t h a t f o r  Kalmia  from p o s i t i v e t o n e g a t i v e , Bog.  changes  orb a officinalis  boreale  from n e g a t i v e  polifoliaxDrosera  Carex to  rotundifolia  i n Wade's Bog as opposed t o Ogg's  However, the commonest b e h a v i o r i s f o r r t o change i n  s t r e n g t h but not i n s i g n , o r t o change a s m a l l amount i n s i g n , from one bog t o a n o t h e r .  D i f f e r e n t c o r r e l a t i o n s i n each bog f o r  a p a r t i c u l a r s p e c i e s p a i r would be expected i f ( a s  postulated)  s  Wade's Bog i s s u c c e s s i o n a l l y more mature t h a n Ogg's B o g , and if  s p e c i e s i n t e r a c t i o n s do change w i t h s u c c e s s i o n , as  Greig-  Smith (1964) and Kershaw (1964) m a i n t a i n . Each i n d i v i d u a l case has i n t e r e s t i n g f e a t u r e s ,  but i t  is  not f e a s i b l e t o d i s c u s s the c o r r e l a t i o n b e h a v i o r of a l l p o s s i b l e s p e c i e s p a i r s . A good example of the t y p e o f  inform-  a t i o n t h a t can be o b t a i n e d i s a f f o r d e d by the s p e c i e s  pair  Myrica  gale nalis  galexSanguisorba officinalis.  I n Wade's B o g ,  Myrica  i s s t r o n g l y p o s i t i v e l y c o r r e l a t e d w i t h Sanguisorba at the 1 m  P<0.001)  quadrat  2  ( r =.+0.74, P<0.01) and 0.25 m  2  offici-  ( r = +0.99,  s i z e s . F u r t h e r m o r e , i n Wade's B o g , 6 7% o f  i n t e r s p e c i f i c c o r r e l a t i o n s o f Myrica  are n e g a t i v e ,  and  the  44 i s the o n l y species w i t h a s i g n i f i c a n t l y p o s i t i v e  Sanguisorba  c o r r e l a t i o n w i t h Myrioa.  In c o n t r a s t ,  i n Ogg's B o g , r f o r  changes from +0.40 t o +0.10 t o - 0 . 2 8 i n the  MyrioaxSanguisorba  2 1, 0 . 2 5 , and 0.01 m for  quadrat s i z e s , r e s p e c t i v e l y . My e x p l a n a t i o n  t h i s behavior i s that i n early successional stages,  n i t r o g e n - f i x i n g a c t i v i t y o f M. gale negative effects  the  b e n e f i c i a l l y offsets  the  of i t s dense, v i g o r o u s , shrubby g r o w t h .  C o n s e q u e n t l y , many o t h e r s p e c i e s are a b l e t o compete on f a i r l y e q u a l f o o t i n g w i t h Myrioa.  As s u c c e s s i o n p r o g r e s s e s ,  Myrioa's  c o m p e t i t i v e a b i l i t y a s s e r t s dominance t o the e x t e n t t h a t o n l y i s a b l e t o perform s u c c e s s f u l l y i n c o m p e t i t i o n w i t h  Sanguisorba it.  The d e c i d u o u s , a r o m a t i c , h i g h l y o i l y l e a v e s o f M.  gale  suggest t h a t a l l e l o p a t h y may a l s o be i n v o l v e d here (wet, Sphagnum  would be an i d e a l medium f o r a w a t e r - s o l u b l e ,  spongy  allelo-  pathic chemical). A n o t h e r i n t e r e s t i n g aspect o f i n t e r s p e c i f i c c o r r e l a t i o n i n v o l v e s comparisons between d i f f e r e n t  growth forms. I n both  bogs, about 77% of a l l c o r r e l a t i o n c o e f f i c i e n t s between a l l grass, all  r's  Myrioa  sedge, and r u s h s p e c i e s are n e g a t i v e . between a l l shrubby s p e c i e s gale,  Linnaea  borealis)  are  Only about 57% o f  ( E r i c a c e a e , Empetrum n e g a t i v e . The  shrubby  nigrum, species  appear to be competing l e s s a c t i v e l y w i t h each o t h e r than g r a s s e s and g r a s s - l i k e s p e c i e s ; t h e g r e a t e r v a r i e t y v e g e t a t i v e and r e p r o d u c t i v e c h a r a c t e r s  the  of  i n t h e shrubs may r e f l e c t  an i n c r e a s e d n i c h e d i v e r s i f i c a t i o n and s p e c i a l i z a t i o n t h a t reduces c o m p e t i t i o n between shrubby s p e c i e s  (see S e c t . I I I - H ) .  45 C o r r e l a t i o n - B l a c k w a l l Meadow  I n t e r s p e c i f i c c o r r e l a t i o n , both p o s i t i v e and n e g a t i v e , strongest is  is  i n the s u b a l p i n e meadow (Appendix 2 , T a b l e 9 ) . T h i s  not s u r p r i s i n g ; t h e h i g h d i v e r s i t y and d e n s i t y o f t h e meadow  v e g e t a t i o n , the compressed growing s e a s o n , and t h e heavy f l u s h s h o u l d a l l c o n t r i b u t e t o the s t r o n g  floral  interspecific  c o m p e t i t i o n t h a t l e a d s to s t r o n g c o r r e l a t i o n . The c o r r e l a t i o n p a t t e r n s o f t h e t h r e e co-dominant of  B l a c k w a l l Meadow are i n t e r e s t i n g .  with V a l e r i a n a  s i t e h e n s i s are  o n l y 31%; w i t h Lupinus robust,  71% o f a l l c o r r e l a t i o n s  negative; with F e s t u o a  latifolius,  species  about  viridula,  52%. Valeriana  is a  s t r o n g l y rhizomatous t a l l forb with l a r g e l e a v e s .  It  has the h i g h e s t average c o v e r (25%) o f a l l the s p e c i e s i n t h e meadow, and i t c l e a r l y dominates most s p e c i e s w i t h which c l o s e l y c o - o c c u r s . Festuoa bunchgrass. Festuoa  i s a medium-height,  narrow-leafed  The low p e r c e n t a g e o f n e g a t i v e c o r r e l a t i o n s  i s due i n p a r t t o i t s l a c k o f v e g e t a t i v e  A l s o , since i t i s a grass,  with  reproduction.  i t s h o u l d not compete as  w i t h the showy-flowered f o r b s t h a t c o n s t i t u t e  it  intensely  the b u l k o f the  meadow v e g e t a t i o n , as i t does w i t h o t h e r g r a s s e s or as the do w i t h t h e m s e l v e s .  Lupinus,  though a l a r g e , d e n s e l y  forbs  robust  s p e c i e s , has n e a r l y equal numbers o f p o s i t i v e and n e g a t i v e c o r r e l a t i o n s . A g a i n , as w i t h Myrioa it  may be t h a t Lupinus  the b e n e f i c i a l e f f e c t s  ' d o m i n a t i n g q u a l i t i e s are tempered by of i t s n i t r o g e n  Only 4/13 or 31% o f t h e r ' s Castilleja  miniata  are  i n the sphagnum b o g s ,  gale  positive  fixation.  w i t h the  hemiparasitic  (Pedicularis braoteosa,  the  46 o t h e r h e m i p a r a s i t i c s p e c i e s , has too few c o r r e l a t i o n c o e f f i c i e n t s t o pronounce u p o n ) . C a s t i l l e j a s  o n l y p o s i t i v e v o f any  1  (r = +0.44)  i s w i t h Lupinus  strength  ; n i t r o g e n - f i x a t i o n can  latifolius  be i m p l i c a t e d i n t h i s c o r r e l a t i o n . T h u s , a l t h o u g h  Castilleja  has some v e r y p o s i t i v e i n t e r s p e c i f i c a s s o c i a t i o n s (see  para-  graphs on a s s o c i a t i o n i n the s u b a l p i n e meadow), c o - o c c u r r e n c e w i t h i t depresses t h e performance o f i t s a s s o c i a t e d  species,  which one might s a f e l y presume are t h e h o s t p l a n t s i n most cases. C o r r e l a t i o n s between the meadow r e p r e s e n t a t i v e s Compositae and between a l l s p e c i e s o f g r a s s e s , wood rushes show d i f f e r e n t p a t t e r n s .  of the  sedges, and  67% o f a l l c o r r e l a t i o n s  between Compositae are p o s i t i v e , compared t o o n l y 45% between t h e g r a m i n o i d s p e c i e s . A g a i n , t h i s d i f f e r e n c e c o u l d be due t o g r e a t e r n i c h e s p e c i a l i z a t i o n i n the s p e c i e s o f Compositae, s p e c i a l i z a t i o n t h a t a l l o w s them t o c o e x i s t more s u c c e s s f u l l y t h a n the g r a m i n o i d s (see S e c t .  III-H).  O v e r a l l p a t t e r n s o f a s s o c i a t i o n and c o r r e l a t i o n .  Association  The  S a l t Marsh has by f a r the h i g h e s t average 2  value of a l l p o s s i b l e x  absolute  2 v a l u e s (|x | ) as w e l l as the  highest  percentage o f s i g n i f i c a n t i n t e r s p e c i f i c a s s o c i a t i o n s ( T a b l e 9 ) . Strong environmental s t r e s s o p e r a t i n g w i t h i n a h a b i t a t produces s t r o n g m i c r o s i t e s p e c i f i c i t y ,  heterogeneous usually for  e i t h e r t h e upper marsh meadow or t h e l o w e r mud f l a t s , and i s  TABLE 9. Summary o f s p e c i e s  | X I (mean | x2 I ) °"° s i g n i f i c a n t for a l l possible . r's interactions  % significant Community  S a l t Marsh Wade's Bog Ogg's Bog Blackwall Meadow  47  interactions.  x  2  97.5 35.5 82.0 84.3  23.3 3.8 5.2 4.4  10.6 17.3 11.1 14.3  0.29 0.26 0.24 0.33  p r o b a b l y r e s p o n s i b l e f o r t h e s e h i g h v a l u e s . Wade's Bog has lowest  |x2|  \v\  2  the  and by f a r the l o w e s t p e r c e n t a g e o f s i g n i f i c a n t  These low f i g u r e s are p r o b a b l y due t o t h e low h a b i t a t  x s. 2 ,  hetero-  g e n e i t y and r e l a t i v e l y advanced s u c c e s s i o n a l s t a t e o f t h i s bog. Ogg's Bog has much s t r o n g e r  interspecific association  Wade's Bog, c o n v e r s e l y due t o a much g r e a t e r h a b i t a t geneity  than hetero-  (pronounced hummock-hollow m i c r o t o p o g r a p h y , bog  i s l a n d s , v a r i a b l e peat depth) and an e a r l i e r  successional  s t a t u s . B l a c k w a l l Meadow has a h i g h p r o p o r t i o n o f X ' s and an i n t e r m e d i a t e 2  A  from f a i r l y  lx 2 l  forest  significant  5 wi~h •i c -u h I-r i•n t-•-e r p r e t^ as  r e s u-l it i• n g  s t r o n g m i c r o s i t e s p e c i f i c i t y b l u r r e d by a h i g h  degree o f i n t e r s p e c i f i c c o m p e t i t i o n and (perhaps) toned-down by r e l a t i v e successional  maturity.  48  Correlation  If  s p e c i e s d i s t r i b u t i o n were a complete continuum, t h e r e  s h o u l d be a l l degrees o f p o s i t i v e and n e g a t i v e  correlation  w i t h i n a g i v e n p l a n t community. C i r c u m n e u t r a l r'-s s h o u l d  pre-  dominate because the p r o b a b i l i t y o f a g i v e n v a l u e o f r d e c r e a s e s as a f u n c t i o n o f the extremeness o f r (Byer 1970). A frequency  c u r v e o f the v a l u e s o f r s h o u l d be near normal  w i t h a peak near z e r o and t a i l s c o n t i n u o u s l y f a l l i n g on both sides  (Byer 1970). F i g u r e 12a-d i n d i c a t e s  t h a t t h i s i s so o n l y  f o r the s u b a l p i n e meadow, the c u r v e s f o r the two sphagnum bogs and the s a l t marsh b e i n g skewed s l i g h t l y t o the l e f t o f z e r o ; i.e.,  t h e r e are more n e g a t i v e than p o s i t i v e  correlations frequency  i n the l a s t t h r e e communities.  d i s t r i b u t i o n s of s h i f t s  interspecific Furthermore,  o f g i v e n magnitudes i n v  v a l u e s w i t h r e d u c t i o n i n quadrat s i z e ( F i g . 13a-d) that, i n general, decreasing  indicate  p o s i t i v e c o r r e l a t i o n diminishes with  quadrat s i z e . P o s i t i v e c o r r e l a t i o n s h o u l d be reduced  a t c l o s e r q u a r t e r s , b o t h because o f more i n t e n s e c o m p e t i t i o n and a l s o r e d u c t i o n of w i t h i n - q u a d r a t  heterogeneity (Greig-Smith  1964; Kershaw 1964; Byer 1 9 7 0 ) . The means o f the a b s o l u t e v a l u e s o f a l l c o e f f i c i e n t s correlation  (|r|)  of  f o r each community are a l s o g i v e n i n Table 9.  As H u r l b e r t (1969) p o i n t s o u t ,  correlation coefficients  p r o b a b l y more v a l i d i n d i c a t o r s o f i n t e r s p e c i f i c t h a n are measures o f a s s o c i a t i o n . e x h i b i t the h i g h e s t  |r|  are  competition  The s u b a l p i n e meadow  species  i n d i c a t i v e , I t h i n k , of r e l a t i v e l y  s t r o n g e r i n t e r s p e c i f i c c o m p e t i t i o n i n the meadow. The low \v\  Fig. random  12.  Frequencies  quadrat  s i z e s .  of  r  values  for  the  Fig.13.  three i n  r  Frequencies  values  with  of  shifts  reduction  i n  of  given  quadrat  magnitudes  size.  50  of t h e sphagnum bogs i s p r o b a b l y a consequence o f a low degree o f c o m p e t i t i o n . The i n t e r m e d i a t e v a l u e o f \~r\ f o r t h e  salt  marsh may be i n t e r p r e t e d as r e p r e s e n t i n g an i n t e r m e d i a t e  level  o f c o m p e t i t i o n between s p e c i e s o f the marsh, where the v e g e t a t i o n i s f a i r l y c o n t i n u o u s but t h e r e are  (among o t h e r  t h i n g s ) fewer s p e c i e s , a l o n g e r growing s e a s o n , and much l e s s r e l i a n c e on i n s e c t p o l l i n a t o r s than i n the s u b a l p i n e meadow. For a l l f o u r c o m m u n i t i e s , f u r t h e r and b o t h x ' 2  s a n <  significantly) are s t r o n g e s t  i  c o r r e l a t i o n s between r-'s  C o l e ' s c o e f f i c i e n t s are p o s i t i v e ( u s u a l l y  f o r a l l quadrat  s i z e s . O v e r a l l , these c o r r e l a t i o n s  at the s m a l l e s t quadrat  because the s m a l l quadrats  can d e t e c t  l e v e l s , presumably the a s s o c i a t i o n patterns  t h a t are on a s m a l l enough s c a l e t o be comparable t o correlation  the  patterns.  I n summary, t h e p a t t e r n s o f i n t e r s p e c i f i c a s s o c i a t i o n and c o r r e l a t i o n may be i n t e r p r e t e d as i n d i c a t i n g an i n t e r p l a y o f e n v i r o n m e n t a l ( p h y s i c a l ) and c o m p e t i t i v e ( b i o l o g i c a l ) f a c t o r s . T h i s i n t e r p r e t a t i o n i m p l i e s t h a t the s t r e s s of the p h y s i c a l environment i s h i g h e s t i n the s a l t marsh, i n t e r m e d i a t e i n the b o g s , and l o w e s t i n t h e s u b a l p i n e meadow. I n c o n t r a s t , s p e c i f i c competition i s strongest  i n the s u b a l p i n e meadow, o f  medium s t r e n g t h i n t h e s a l t marsh, and weakest i n the bogs.  inter-  sphagnum  51 C. Chromosome numbers and p o l y p l o i d y .  Recent s t u d i e s  i n p l a n t cytogeography have been much  concerned w i t h the r e l a t i o n s h i p o f angiosperm p o l y p l o i d y t o environment. The h y p o t h e s i s t h a t p o l y p l o i d s are p h y s i o l o g i c a l l y f a v o r e d over d i p l o i d s i n extreme environments  (Hagerup 19 3 1 ;  Love and Love 1949, 19 57; Mooney and Johnson 1965) has been much d i s p u t e d (Bowden 1940; G u s t a f f s o n 1948; Johnson and Packer 1965; Johnson et al. 1965; Favarger 1967; S t e b b i n s 1950, 1971b). A.umore a c c e p t e d view i s t h a t p o l y p l o i d s have been a t a s e l e c t i v e advantage i n p h y s i c a l environments c h a r a c t e r i z e d by frequent,  d r a s t i c , i r r e g u l a r l y recurrent  and Packer 1965; S t e b b i n s 1971b) and ( o r ) gradients  disturbances  (Johnson  sharp e c o l o g i c a l  ( B e l l 19 6 4 ) , presumably because the g r e a t  genetic  v a r i a b i l i t y r e s u l t i n g from h y b r i d i z a t i o n and subsequent p o l y p l o i d i z a t i o n g i v e s the p o l y p l o i d s a b e t t e r chance o f t h a n comparable d i p l o i d s . I t  survival  i s a l s o b e l i e v e d t h a t most p o l y -  p l o i d s have been d i f f e r e n t i a l l y s u c c e s s f u l i n p o s t g l a c i a l r e c o l o n i z a t i o n o f bare g r o u n d , not n e c e s s a r i l y because o f b e t t e r p o l y p l o i d c o l o n i z i n g a b i l i t y , but because c o n d i t i o n s  at  the margins o f t h e i c e sheet and on r e c e n t l y uncovered ground a l l o w e d f o r m a t i o n and e s t a b l i s h m e n t w i t h new genotypes  of p o l y p l o i d  derivatives  ( S t e b b i n s 1950; Johnson et al. 1965).  P o l y p l o i d y would s t a b i l i z e t h e s e l e c t i v e l y f a v o r e d genotypes by r e d u c i n g g e n e t i c r e c o m b i n a t i o n and e l i m i n a t i n g the  sterility  t h a t i s o f t e n t h e f a t e o f d i p l o i d h y b r i d s (Mosquin 1966; S t e b b i n s 1971b). F u r t h e r m o r e , i n t e r - o r p o s t - g l a c i a l i m m i g r a t i o n o f d i p l o i d s p e c i e s may n o t ' h a v e had s u f f i c i e n t time t o  reduce  52  the p o l y p l o i d frequency (Reese 1961). I t appears t h a t e n v i r o n m e n t a l and h i s t o r i c a l e x p l a n a t i o n s are more v a l u a b l e than  those  based on i n t r i n s i c p h y s i o l o g i c a l p r o p e r t i e s o f p o l y p l o i d s . Most o f t h e p e r t i n e n t  s t u d i e s have used p o l y p l o i d  frequencies  c a l c u l a t e d from f l o r a s o f v a r i o u s g e o g r a p h i c a l a r e a s . Most  (see,  however, P i g n a t t i 1960; F u n a b i k i 1960, 1967) have i g n o r e d t h e r e l a t i v e importance o f p o l y p l o i d s p e c i e s i n the  vegetation,  u n d e r s t a n d a b l y s o , s i n c e t h e presence o f a s p e c i e s i s o f more p h y t o g e o g r a p h i c s i g n i f i c a n c e than i t s  abundance.  N e v e r t h e l e s s , i t would be i n t e r e s t i n g t o a s s e s s the  role  of p o l y p l o i d y i n q u i t e d i f f e r e n t v e g e t a t i o n types w i t h i n r o u g h l y the same g e o g r a p h i c a r e a . Data are p r e s e n t e d here f o r t h e percentage  o f angiosperm p o l y p l o i d y i n both the f l o r a and  v e g e t a t i o n o f the f o u r communities i n the p r e s e n t Chromosome numbers were determined p r i m a r i l y  study. from  f l o w e r - b u d m a t e r i a l , a l t h o u g h a few r o o t - t i p squashes were a l s o made.  Flower buds were c o l l e c t e d from f i e l d p o p u l a t i o n s and  f i x e d i n 3:1 e t h y l a l c o h o l and a c e t i c a c i d . M e i o t i c  counts  were made from m i c r o s p o r o c y t e s squashed i n i r o n h a e m a t o x y l i n . Root t i p s were c o l l e c t e d i n t h e f i e l d ,  pretreated  with  8 - h y d r o x y q u i n o l i n e , f i x e d i n 3:1 e t h y l a l c o h o l and a c e t i c  acid,  and a l s o squashed i n i r o n h a e m a t o x y l i n . Camera l u c i d a drawings of the v a r i o u s chromosome complements are p r e s e n t e d  i n Figures  14-110. The r e s u l t s are t a b u l a t e d i n T a b l e 10. The s p e c i e s  are  arranged i n o r d e r o f d e c r e a s i n g importance v a l u e . A l l counts made by the a u t h o r are from m a t e r i a l c o l l e c t e d a t the sites.  respective  Chromosome numbers marked w i t h an a s t e r i s k are from t a x a  Fig.  14.  Deschampsia  Fig.  15.  Festuca  Fig.  16.  Triglochin  maritimum  Fig.  17.  Salicornia  virginica  Fig.  18.  Plantago  Fig.  19.  Juncus  Fig.  20.  Carex  lyngbyei  3  n  =  36.  Fig.  21.  Glaux  maritima,  n  -  15.  Fig.  2 2., P o t e n t i l l a p a c i f i c a ,  Fig.  23.  Agrostis  Fig.  24.  Stellaria  humifusa,  Fig.  25.  Trifolium  wormskjoldii  Fig.  26.  Scirpus  Fig.  27.  Puccinellia  Fig-  28.  Spergularia  Fig.  29.  Hordeum  Fig.  30 . L i l a e o p s i s  oespitosa  rubra,  n  balticus  3  3  n =  18  6  =  - 14.  n  n  14  3  .  - 13. = 16 .  n  3  =  n  •  40.  =  n  pumila  48  =  exarata,  cernuus  =  n  3  n  3  n  3  13.  21.  =  maritima  n -  3  30.  n  - 21.  canadensis  brachy antherum  3  3  occidentalis  3  n  - 18.  n  - 14. n  - 22.  53 b  • 4 •  •  •a  i  1  17  • 9 %  18  16  •  •••••V  •  20 19  22 21  54ou  Fig-  31.  Myrica  Fig.  32.  Apargidium  Fig.  33.  Carex  obnupta,  Fig.  34.  Carex  pluriflora,  Fig.  35.  Agrostis  Fig.  36.  Sanguisorba  Fig.  37.  Ledum  Fig.  38.  Vaccinium  Fig.  39.  Drosera rotundifolia, n =  Fig.  40 . K a l m i a p o l i f o l i a ,  Fig.  41.  Fig-  42 . T r i e n t a l i s  Fig.  43 . C a r e x c a n e s c e n s , n - 28  Fig.  44.  Tofieldia  Fig.  45.  Linnaea borealis,  Fig.  46.  Rhynchospora  Fig.  47 . P l a n t a g o  Fig.  48.  Fig.  49 . G e n t i a n a s c e p t r u m ,  Fig.  50.  48  gale, n -  boredle, n  3  —  i  37  n -  n = 26  = 7  aequivalvis, n  officinalis, n  14  =  g r o e n l a n d i c u m . n = 13  Empetrum  o x y c o c c u s , n = 24  nigrum,  Gaultheria  n  10  - 12 - 13  n  arctica,  n = ca.  glutinosa, n  42-44  - 15  n = 16  alba,  n =  macrocarpa, n shallon,  n n =  13 - 12 - 44  13  Calamagrostis nutkaensis, n —  14  • ••  *•_•*/ •••• 46  - A  •SA  47  48 0  I * 45 49  Zum<L  50  55  CL/  dilatatum, n =  Fig.  51.  Fig.  52 . S c i r p u s  cespitosus  Fig.  53 . C o p t i s  asplenifolia,  Fig.  54.  trifolia,  Fig.  55 . J u n c u s  Fig.  56 . G e n t i a n a  Fig.  57.  Vaccinium  Fig-  58.  Vaccinium  Fig.  59 . V a c c i n i u m  Fig.  60.  Maianthemum  Coptis  52.  n = 9 .  n - 9  •  s u p i n i f o r m i s , n = ca.  = ca.  ovatum,  n - 12  vitis-idaea  3  56 13.  •  n =  uliginosum, n =  12. 24.  c r i s t a -g a l l i ,  51.  Fig.  61.  Fig-  62 . C a r e x p a u c i f l o r a  •Er wphorum  =  douglasiana. n  Nephrophyllidium n  - ca.  n  3  18.  L  p6ly>stachioh 3  3  n - ca .  n -  37.  30  5Sb  60  61 62  5 6ox  Fig.  63 . V a l e r i a n a s i t c h e n s i s  Fig.  64.  Lupinus  latifolius  3  Fig.  65.  Festuca  viridula,  n -  Fig.  66.  Erigeron  Fig.  67.  Anemone  Fig.  68.  Erythronium  Fig.  69 . P o t e n t i l l a  Fig.  70.  Vaccinium  scoparium  Fig.  71.  Claytonia  lanceolata,  Fig.  12.  Arenaria  Fig.  73.  Antennaria  Fig.  74.  Veronica  cusickii  Fig.  75.  Agoseris  aurantiaca  Fig.  76.  Fhleum  alpinum,  Fig.  77.  Arnica  latifolia  48.  14.  - 9.  n  3  occidentalis  48.  - ca.  n  peregrinus  - ca.  n  3  2n =  3  16.  grandiflorum  3  2n  flabellifolia  3  n =  capillaris lanata, 3  n  -  3  n  n  3  - 12 . 2n =  - 11.  3  n  n  -  14  •  n  -  36  •  3  n  - 18.  14. -  =  19.  16.  24. 14.  Stb  75  77  Fig.  78.  Luzula  h i t c h c o c k i i , n - 12.  Fig.  79.  Thalictrum  Fig.  80 . A c h i l l e a m i l l e f o l i u m , n =  Fig-  81.  Fig.  82 . E l y m u s  glaucus,  Fig.  83.  Silene  parryi, n =  24.  Fig.  84.  Arnica  mollis, n =  ca. 38 .  Fig.  85.  Penstemon  Fig.  86.  Poa  Fig.  87.  Senecio  Fig.  88.  Eieracium  Fig.  89.  Luzula  Fig.  90.  Sedum  Fig.  91.  Castilleja  Fig.  92.  Pedicularis  Fig-.  93.  Phlox  Trisetum  occidentale, n =  n = 14.  spicatum,  14.  n =  n = 8.  procerus,  cusickii,  14.  n -  integerrimus,  gracile,  n =  20  - 9.  n  12.  spicata, n -  n - 8.  lanceolatum, miniata,  n - 12.  bracteosa, n  diffusa, n  27  =  7.  =  8  94.  Potentilla  95.  Carex  96.  Epilobium alpinum  97.  Delphinium nuttallianum  98.  Castilleja  parviflora  99.  Ranunculus  eschscholtzii  100.  Sibbaldia  101.  Juncus  102.  Hydrophyllum  103.  Senecio triangularis  104.  Vaccinium deliciosum  105.  Mitella  pentandra  3  n =  7.  106.  Luetkea pectinata  3  n =  9.  107.  Pedicularis  108.  Phyllodoce  109.  Veratrum  110.  7eroniea w o r m s k j o l d i i  diversif olia  spectabilis  3  3  n  - ca.  n  -  procumbens  drummondii  n  3  42.  18.  n  3  n  3  n  3  fendleri,  racemosa  60. =  n  3  3  3  18.  n -  20.  n -  24.  n =  3  16.  -  7.  =  empetriformis  viride  12.  n -  3  16.  -  n ca.  3  ca.  -  3  8.  n -  16.  n 3  n =  9.  24  59 for  w h i c h no number has been r e p o r t e d p r e v i o u s l y . Each s p e c i e s has been a s s i g n e d a b a s i c chromosome number  o b t a i n e d o r i n f e r r e d from t h e l i t e r a t u r e , e s p e c i a l l y D a r l i n g t o n and W y l i e ( 1 9 5 5 ) , subsequent  IOBP R e p o r t s , and  T a y l o r and M u l l i g a n ( 1 9 6 8 ) . B a s i c numbers w h i c h a r e  themselves  p r o b a b l y o f p o l y p l o i d o r i g i n ( e g . , x = 12 f o r many E r i c a c e a e ; x  = 15 f o r T o f i e l d i a ;  here as d i p l o i d .  x = 10 f o r A r n i c a ) have been r e t a i n e d  For each s i t e , percentages  of p o l y p l o i d y i n  b o t h the f l o r a and v e g e t a t i o n have been c a l c u l a t e d and are l i s t e d at t h e bases o f the c o r r e s p o n d i n g t a b l e s and i n T a b l e 1 1 . In  view o f t h e e x c e p t i o n a l c y t o l o g y o f the Cyperaceae and  Juncaceae  ( N o r d e n s k i o l d 19 5 1 ; D a v i e s 19 56; S t e b b i n s 1 9 7 1 b ) , a  b a s i c number of 10 has been a r b i t r a r i l y chosen f o r and Junous.  Soiryus,  Carex,  T h i s i s i n t e n d e d as a compromise. Both  H e i l b o r n (1939) and Wahl (1940) c o n s i d e r e d x = 7 t o be the o r i g i n a l b a s i c number o f t h e genus C a r e x , detected  a l t h o u g h Wahl a l s o  s e r i e s based on x = 5, 6, and 8. Love et al. (1957)  proposed x = 5 as the p r i m a r y b a s i c number o f b o t h Carex J u n o u s , w h i l e Snogerup (1963) m a i n t a i n e d t h a t i n Junous  and the  p r i m a r y b a s i c number can be as h i g h as x = 25. The a n e u p l o i d numbers i n Carex,  Scirpus,  and Junous  have p r o b a b l y a r i s e n  t h r o u g h a c o m b i n a t i o n o f t r u e p o l y p l o i d y and p a r t i a l agmatop l o i d y , o r endonuclear p o l y p l o i d y . A t any r a t e , the  chromosome  numbers o f the above genera i n t h i s study are h i g h enough t o be c o n s i d e r e d p o l y p l o i d even i f t h e - b a s i c number i s as h i g h as x  = 20. The  results  i n d i c a t e t h a t l e v e l s of p o l y p l o i d y i n t h e s e  f o u r communities a r e f a i r l y h i g h , and t h a t t h e l e v e l w i t h i n a  60 TABLE 10. Chromosome numbers, p o l y p l o i d y , and importance of -species o f t h e f o u r s t u d y c o m m u n i t i e s .  Species  Chromosome No. , n  Salt Desohampsia c e s p i t o sa Festuca rubra Triglochin maritimum Salicornia virginica Plantago maritima Juncus balticus Carex lyngbyei Glaux maritima Potentilla pacifica Agrostis exarata Stellaria humifusa Trifolium wormskg oldii Scirpus cernuus Puccinellia pumila Spergularia canadensis Distichlis spicata Hordeum brachyantherum Lilaeopsis occidentalis Oenanthe sarmentosa Plantago macrocarpa  Basic No., x  Polyploid  Importance value ( I . V . )  Marsh  13  7  +  38.6  21 48  7 6  + .+  24. 5 21. 0  18  9  +  17 . 8  6 40 36 15 14  6 10 10 15 7  —  -+  16.9 16 . 8 14. 3 13. 9 7. 2  14 13 16  7 13 8  +  7. 1  —  +  6. 0 3. 5  30 21 18  10 7 9  + + +  3.3 2. 7 2. 0  5 7  +  1.8 1. 8  11  +  0.4  11 6  + +  0.1 0.1  20 14  a  22 22 12  b D  17/20 o r 85% o f f l o r a is polyploid  + +  Sum o f p o l y p l o i d I . V . ' s / 2 = 81.5% of vegetation is polyploid  Wade's Bog Carex p l u r i f l o r a Apargidium boreale Agrostis aequivalvis Carex obnupta  26 9 7 37, c a .  values  38  10 9 7  + -  30.1 27.2 15.9  10  +  15.9  61 TABLE 10.  (Continued)  Species  Chromosome No. , n  Sanguisorba officinalis Katmia polifolia Vaooinium oxyoooous Carex canesoens Drosera rotundifo lia Ledum groenlandioum Trientalis a r c t i o a ca. Empetrum nigrum Myrioa gale TofieIdia g l u t i n o sa Gentiana douglasiana Linnaea borealis Maianthemum dilatatum Rhynohospora alba Vaooinium vitisidaea Scirpus oespitosus ca. Junous s u p i n i f o r m i s ca. Vaooinium uliginosum Gaultheria shatton Gentiana soeptrum Coptis asplenifolia Coptis t r i f o l i a Vaooinium ovatum  Basic No. , x  Polyploid  Import ance value ( I . V . )  14  7  +  15. 1  12 24 28 10  12 12 10 10  -  14. 13. 11. 11.  13 42-44 13 48 15  13 11(?) 13 8 15  -  13  13  —  1. 2  16 18  8 9  + +  1. 2 1. 0  13 12  13 12  -  0. 7 0.4  5 2 56 24  10 10 12  + + +  0. 3 0. 2 0. 2  44 13* 9  11 13 9  +  0. 2 0 .2 0 .. 2  9 12  9 12  13/27 o r 48 .1% flora is polyploid  + +  -  0 3 9 2  9. 1 8.9 5.2 4. 9 4.6  + —  + —  —  -  0.,1 0 ,. 1  -  polyploid Sum of I.V . ' s / 2 == 51.6% of v e g e t a t i o n i s polyploid  of  Ogg's Bo g Myrioa gate Apargidium boreate Carex obnupta Carex pluriflora Agrostis aequivalvis  48 9 37 26 7  8 9 10 10 7  +  -  + +  —  36 .1 , 18 ., 4 13. . 7 11 . 6 10 . 7  62 TABLE 10.  (Continued)  Species  Sanguisorba officinalis Ledum groenlandioum Vaooinium oxyoooous Drosera rotundifolia Kalmia polifolia Empetrum nigrum Trientalis arctioa Carex canescens To f i e I d i a glutinosa Linnaea borealis Rhynohospora alba Plantago macrocarpa Gaultheria shallon Gentiana sceptrum Calamagrostis nutkaensis Maianthemum dilatatum Scirpus cespitosus Coptis asplenifo lia Coptis t r i f o l i a Juncus supiniformis Desohampsia oespitosa Gentiana douglasiana Vaooinium ovatum Vaooinium vitisidaea Cornus unalasohkensis Vaooinium uliginosum Nephrophyllidium orista-galli Eriophorum poly stachion Carex p a u o i f l o r a Ly s i o h i t u m americanum  Chromosome No. , n  ca.  ca.  ca.  ca.  ca.  Basic No. , x  Polyploid  Importance value ( I . V . )  14  7  +  9. 3  13 24 10  13 12 10  -  8.1 7.5 6.1  12 13 42-44 28 15  12 13 11(?) 10 15  16 13 12 44 13* 14  8 13 6 11 13 7  +  -+ +  -  5.8 5.5 5.4 5.0 4.7  -+  4.0 3.9 3.8 3.3 2. 5 2.0  + +  18  9  +  2. 0  52 9  10 9  +  1.6 1.4  9 56 13  9 10 7  + +  1.4 1.1 0.9  13  13  -  0.6  12 12  12 12  -  0. 6 0.4  22  11  +  0.4  24  12  +  0.3  51  17  +  0.3  30  10  +  0.2  10 14(?)  +  0.2 0.1  d 14 3 7  d  -  -  -  63 TABLE 10 (Continued)  Species  Habenaria saccata Goody era oblongifo l i a Junous effusus Juncus ensif olius  Chromosome No., n  Basic No., x  21 d 15  21 15  40< 20  10 10  c  (  Polyploid  Importance value ( I . V . )  0.1 0.1 0.1 0.1  + +  Sum o f p o l y p l o i d I . V . ' s / 2 = 54.5% of vegetation i s polyploid  22/39 o r 56.4% of f l o r a i s polyploid B l a c k w a l l Meadow Valeriana c a . 48 8 sitchensis Festuca viridula 14 7 Lupinus latifolius c a . 48 12 Erigeron 9 9' peregrinus '8 Anemone 2n = 16 occidentalis (root t i p ) Potentilla 14 7 flabellifolia Erythronium 2n = 24 12 grandiflorum (pre^meiotic mitosis) Vaccinium •12* 12 scoparium Claytonia 2n = 16 8 lanceolata (pre-meiotic mitosis) Arenaria 11 11 capillaris Antennaria lanata 14* 7 Veronica cusickii 3 6* 9 Agoseris 18 9 aurantiaea Phleum alpinum 14 7 Arnica latifolia 19 10 Luzula hitch12* 6 cockii^ Thalictrum 2 8* 7 occidentale AchiIlea 27 9 mi Ilefolium Trisetum spicatum 14 7 Carex rossii Not Not  counted  counted  +  24. 9  + +  24. 3 21. 8 12. 4  -  11. 9  +  10. 4  -  7. 0  -  6. 9  -  6.5  -  6. 3  + + +  6. 2 5. 3 4. 8  + + +  4. 8 4. 7 4. 6  +  3. 7  +  3. 5  +  3. 2  64 TABLE 10.  (Continued)  Species  Elymus glaucus Silene parryi Arnica mollis Pens.temon procerus Poa cusickii Senecio integerrimus Eieracium gracile Luzula spicata Sedum lanceolatum Castilleja miniata Pedicularis bracteosa Phlox d i f f u s a Potentilla diver sifolia Carex spectabilis Epilobium alpinum DeIphinium nuttallianum Castilleja parviflora Ranunculus eschscholtzii Sibbaldia prooumbens Junous drummondii HydrophyIlum fendleri Senecio triangularis Vaooinium deliciosum Mitella pentandra Luetkea peotinata Pedicularis raoemosa Phyllodoce empetrif'or mis Saxifraga occidentalis Trollius laxus Veratrum viride  Chromosome No., n  Basic No., x  Polyploid  14 24 38 8 14 20  7 12 10 8 7 10  + + +  9 12 8 12 8  9 6 8 12 8  -  7 70  7 7  +  0. 8 0.7  42 18 16*  10 9 8  + + +  0.6 0.5 0.5  12  12  -  0.4  16  8  +  0.4  7  7  —  0.3  6 0 18  10 9  + +  0.2 0.2  20  10  +  0.2  24*  12  +  0.2  7 9 8  7 9 8  -  0.1 0.1 0.1  24  12  +  0.1  10  +  0.1  8 8  -  ca.  ca. ca.  ca.  19 8 16  f r  g  Importance value ( I . V . )  2.5 2.2 2.0 2.0 1.9 1.8  + +  1.7 1.4 1.2 1.2 0.9  +  -  +  .  0.1 0.1  65 TABLE 10.  (Concluded)  Chromosome No. , n  Species  Veronica joldii  Basic No. , x  Importance value ( I . V . )  9  9  wormsk-  Polyploid  0.1 Sum of p o l y p l o i d I . V . ' s / 2 = 70.3% of v e g e t a t i o n i s polyploid  31/50 o r 62 . 0% of f l o r a i s polyploid  S t e b b i n s and Love (1941). B e l l and Constance ( 1 9 5 7 ) ; T a y l o r and M u l l i g a n ^ A f t e r C a l d e r and T a y l o r ( 1 9 6 8 ) . As r e p o r t e d i n T a y l o r and M u l l i g a n ( 1 9 6 8 ) . ^After Hamet-Ahti (1971). Krause and Beamish ( i n p r e s s ) . P a c k e r (1964).  h  (1968).  g  p a r t i c u l a r a r e a i s not d r a s t i c a l l y d i f f e r e n t whether as a p e r c e n t a g e o f the f l o r a or v e g e t a t i o n . vegetation typescstudied, of  p o l y p l o i d y (about  level  80%). The sphagnum bog v e g e t a t i o n has  (about  intermediate  l e v e l of about  and Seirpus  three  the s a l t marsh has the h i g h e s t  lowest l e v e l  Carex  Of t h e  computed  the  50%) and t h e s u b a l p i n e meadow has an 65% ( T a b l e s 10 & 1 1 ) . Note t h a t i f  are l e f t out o f the c a l c u l a t i o n s ,  the  p o l y p l o i d y l e v e l s f o r t h e bogs are d i s p r o p o r t i o n a t e l y l o w e r e d , i n c r e a s i n g t h e d i f f e r e n c e between l e v e l s i n the bogs and t h e other three  sites.  Since a l l s i t e s  are at e s s e n t i a l l y the same l a t i t u d e and  were a l l c o v e r e d by the P l e i s t o c e n e i c e sheet (Heusser differences  i n l e v e l s o f p o l y p l o i d y cannot be e x p l a i n e d  s a t i s f a c t o r i l y by d i f f e r e n t i a l e f f e c t s  of g l a c i a t i o n or  1960),  66 TABLE 11. Summary o f l e v e l s o f p o l y p l o i d y .  Site  No. of species  20 27 39 50  S a l t Marsh Wade's Bog Ogg's Bog Blackwall Meadow  % ..polyploidy (flora)  % polyploidy (vegetation)  81.5 51. 6 54. 5 70.3  85.0 48.1 56.4 62 . 0  p o s t g l a c i a l r e c o l o n i z a t i o n . R e c o l o n i z a t i o n of a l l  sites  p r o b a b l y proceeded p r i m a r i l y from the area south o f the boundary i n W a s h i n g t o n , a l t h o u g h the T o f i n o a r e a  glacial  could  c o n c e i v a b l y have been reached by c o a s t a l immigrants from r e f u g i a i n the Queen C h a r l o t t e I s l a n d s and P a c i f i c  coastal  A l a s k a (Heusser 1960; S c h o f i e l d 1969; Randhawa and Beamish 1972). E x p l a n a t i o n s based on v a r y i n g degrees o f average e n v i r o n mental " h a r s h n e s s " , also unsatisfactory.  whether i n a c l i m a t i c o r edaphic s e n s e , Most i m p o r t a n t ,  are  comparisons o f measure-  ments o r e s t i m a t e s o f p h y s i c a l parameters among the f o u r  sites  would have l i t t l e meaning because o f t h e d i s p a r i t y o f t h e i r p h y s i c a l e n v i r o n m e n t s , assuming t h a t such measurements w o u l d , if  comparable, have any f i n a l meaning (see S e c t .  III-J).  However, c o r r e l a t i o n s w i t h e n v i r o n m e n t a l r i g o r can be made if  " r i g o r " i s d e f i n e d i n g e n e r a l terms and p a r t i t i o n e d  several aspects.  I n l i n e w i t h the r e a s o n i n g of S t e b b i n s  into (1971b)  and Johnson et al. ( 1 9 6 5 ) , l e v e l s o f p o l y p l o i d y can be r e l a t e d t o the t y p e and degree o f e n v i r o n m e n t a l  disturbance.  67 I n a d d i t i o n t o average c o n d i t i o n s o f the complex such as c l i m a t i c means and n u t r i e n t  environmental  l e v e l s , estimation  o f e n v i r o n m e n t a l r i g o r must i n c l u d e t h e r e l a t i v e a m p l i t u d e s o f e n v i r o n m e n t a l f l u c t u a t i o n s and.-:ther,irr.eguiarity: o r u n p r e d i c t a b i l i t y of these f l u c t u a t i o n s  ( S l o b o d k i n and  Sanders  19 69; W h i t t a k e r 19 7 2 ) . R e g u l a r e n v i r o n m e n t a l f l u c t u a t i o n s  such  as t i d a l f l o o d i n g and d i u r n a l o r s e a s o n a l t e m p e r a t u r e v a r i a t i o n s s h o u l d not d i f f e r e n t i a l l y a f f e c t  l e v e l s of p o l y p l o i d y ,  since  p e r e n n i a l d i p l o i d s s h o u l d be a b l e t o accommodate them as w e l l as comparable p o l y p l o i d s . However, l o n g e r - t e r m , more u n p r e d i c t able disturbances  ( s h o r t o f l o n g - t e r m c l i m a t i c changes  such as  warming o r c o o l i n g t r e n d s ) c o u l d s e l e c t i v e l y f a v o r p o l y p l o i d s . I would c l a s s the r a p i d and u n p r e d i c t a b l e changes m o b i l e substratum and t o p o g r a p h y ,  in  c h a r a c t e r i s t i c of s a l t  as f l u c t u a t i o n s o f t h e l a t t e r t y p e .  marshes,  Changes i n d r a i n a g e and  s e d i m e n t a t i o n p a t t e r n s f r e q u e n t l y o c c u r i n s a l t marshes and are accompanied by s i m u l t a n e o u s e r o s i o n and a c c r e t i o n o f mud f l a t s and marsh (Johannessen  19 64; R e d f i e l d 1965, 1972). I n a d d i t i o n ,  s a l t marsh v e g e t a t i o n has been s u b j e c t fall  to e u s t a t i c  r i s e and  i n sea l e v e l r e l a t e d t o P l e i s t o c e n e g l a c i a t i o n and de-  g l a c i a t i o n (Cooper 1958, 1967; Heusser 1960). Such p h y s i o g r a p h i c changes would be accompanied by b o t h r a p i d e s t a b l i s h m e n t  and  e l i m i n a t i o n o f p o p u l a t i o n s o f marsh s p e c i e s i n newly a v a i l a b l e o r swamped s i t e s ,  respectively.  S u b a l p i n e meadows have e x p e r i e n c e d t h e i n t e r g l a c i a l advance and r e t r e a t of a l p i n e g l a c i e r s , and frequent fires  but  unpredictable  (Douglas and B a l l a r d 1 9 7 1 ) , l a t e snow p a c k s , summer  freezes,  and s o i l d i s t u r b a n c e s  by marmots and pocket  gophers  68 a l l events t h a t may be accompanied by c y c l e s o f e r o s i o n and e s t a b l i s h m e n t o f meadow v e g e t a t i o n i n new, d i s t u r b e d habitats.  These d i s t u r b a n c e s  are s i m i l a r , i n type i f not  t o those o f the s a l t marsh. I n c o n t r a s t , area have no s i m i l a r d i s t u r b a n c e s .  sphagnum bogs i n t h i s  Even the r e g u l a r hummock-  h o l l o w c y c l e s o f bogs (Gorham 1957; Lawrence 1958) apparently self-generated  degree,  are  by t h e bog s p e c i e s , do not r e s u l t  in  any d r a s t i c e r o s i o n , and a r e more o r l e s s p r e d i c t a b l e and self-contained. I t appears,  t h e n , t h a t the d i f f e r e n t  l e v e l s of p o l y p l o i d y  i n t h e s e t h r e e v e g e t a t i o n t y p e s are b e s t e x p l a i n e d by d i f f e r e n t degrees o f e n v i r o n m e n t a l i n s t a b i l i t y . H i s t o r i c a l , m i g r a t i o n a l f a c t o r s have s u r e l y been a major cause o f t h e r e l a t i v e l y h i g h l e v e l o f p o l y p l o i d y i n the o v e r a l l g e o g r a p h i c a r e a , but have had m i n i m a l e f f e c t  on d i f f e r e n c e s w i t h i n the a r e a . E x p l a n a t i o n s  based on i n t r i n s i c p h y s i o l o g i c a l p r o p e r t i e s o f p o l y p l o i d s t h a t f a v o r them i n extreme environments are t h e o r e t i c a l l y and practically  inappropriate.  Environmental i n s t a b i l i t y or u n p r e d i c t a b i l i t y c o u l d , however, r e s u l t  i n higher l e v e l s of p o l y p l o i d y both  because  such u n p r e d i c t a b i l i t y i m p l i e s c o n d i t i o n s (newly a v a i l a b l e disturbed habitats,  rapid fluctuations i n population size)  favorable for h y b r i d i z a t i o n , hybrid establishment,  and  e s t a b l i s h m e n t o f a l l o p o l y p l o i d d e r i v a t i v e s , and because i n c r e a s e d , s t a b i l i z e d genetic v a r i a b i l i t y of the s p e c i e s would p l a c e them at a s e l e c t i v e advantage unpredictable  environment.  the  allopolyploidi n an  69 D.  One  often-neglected  reproductive extent be  Flowering  will  biotic  phenology.  aspect  of p l a n t  phenology. A l l s p e c i e s compete f o r p o l l i n a t i n g  or a b i o t i c .  water, l i g h t ,  and  The  species  f o r the  that  are  outcrossed  the  reproductive  be  an  Figure  angiospermous  species  salt  should  Phenology  ( c f . Mosquin  season at l e a s t  often three  E a c h a r e a was  t r a v e r s e d and  network o f t r a n s e c t s . D u r i n g i n g , rough estimates species Figure  population  the  onset  flowering  commences and  terminates  proportion of a  probably  blooming p e r i o d  curves.  i s o n l y one  emergence o r g e r m i n a t i o n , s e e d s and  yellowing  the  fruits,  o f l e a v e s , and  I t should  be  dynamics  emphasized t h a t  phenophase o f many, s u c h  d i s p e r s a l of ripe death or p a r t i a l  the  by more o r  stem o r c u l m p r o d u c t i o n ,  less the  as  formation  s e e d s and dieback,  in  population  population  w o u l d be more a c c u r a t e l y r e p r e s e n t e d  normal, bell-shaped  particular  to  species  a  flower-  h o r i z o n t a l bars  of a given  f l o w e r i n g , but  week.  noted along  111A-D a r e t a p e r e d _ a t . both-, e n d s , p r o p o r t i o n a l which the m a j o r i t y  and  subalpine  cessation of  The  a  1971).  four times per  and  i n flower.  r a p i d i t y with  unripe  the  flowering behavior  were made o f t h e  t h a t was  to  of  of a l l the  m a r s h , b o g s , and  canvassed during  and  species  from c o m p e t i t i o n  meadow. E a c h community was twice,  for  effort.  flowering phenologies  of the  agents  they  differentiation  HlA-DJ d e p i c t s t h e  any  g r o w i n g s e a s o n as  community, a s p e c t r u m r e s u l t i n g  e v o l u t i o n toward n i c h e  to  competing  r e v e a l a s p e c t r u m o f peak f l o w e r i n g t i m e s f o r t h e particular  is  agents, whether the  also w i l l  nutrients during  marshal resources  synecology  fruits,  that  could  of  F i g . 111. Flowering phenology.  70 b  Triglochin maritimum Carex lyngbyei Glaux maritima Stellaria humifusa Deschampsia cespitosa Juncus balticus Plantago maritima Puccinellia pumila Potentilla pacifica Trifolium wormskjoldii Scirpus cernuus Festuca rubra Spergularia canadensis Agrostis exarata Hordeum brachyantherum Lilaeopsis occidentalis Distichlis spicata Salicornia virginica  A  x  Myrica gale Empetrum nigrum Coptis asplenifolia Carex pluriflora Scirpus cespitosus Coptis trifolia Carex obnupta Kalmia polifolia Gentiana douglasiana Apargidum boreale Trientalis arctica Vaccinium oxycoccus Carex canescens Vaccinium uliginosum Vaccinium vitis-idaea Ledum groenlandicum Agrostis aeguivalvis Tofieldia glutinosa Juncus supiniformis Rhynchospora alba Sanguisorba officinalis Linnaea borealis Drosera rotundifolia Gentiana sceptrum  B  1  r  10 20 30 APRIL  10  20  MAY  __~r —i 31  1  1-  10 20 30 JUNE  10  20  JULY  31  Marsh  = 46  days  Wade's  x  —i  Salt  = 32  10 20 AUGUST  Bog  days  T" —i—  31  10 20 10  SEPTEMBER  Myrica gale Empetrum nigrum Plantago macrocarpa Coptis asplenifolia Eriophorum polystachion Scirpus cespitosus Carex pluriflora Coptis trifolia Carex obnupta Kalmia polifolia Vaccinium ova turn Apargidium boreale Trientalis arctica Vaccinium oxycoccus Carex canescens Vaccinium uliginosum Vaccinium vitis-idaea Nephrophyllidium crista-galli Carex pauciflora Maianthemum dilatatum Ledum groenlandicum Gentiana douglasiana Agrostis aequivalvis Tofieldia glutinosa Gaultheria shallon Juncus supiniformis Cornus unalas$ch'ensis Rhynohospora alba Desohampsia cespitosa Sanguisorba officinalis Linnaea borealis Drosera rotundifolia Calamagrostis nutkaensis Gentiana sceptrum  's Bog  27 days  -J O  Q —I  10  '  1  20  30  APRIL  1  10 MAY  T  20  31  ^  1  10 JUNE  20  r  i  30  10  i  1—  20  JULY  31  10  r~  20  AUGUST  ~I 31  ' 10  r~ 20  SEPTEMBER  70  Anemone occldentalis Erythronium grandiflorum Claytonia lanceolata Luzula hitchcockii Vaccinium scoparium Phlox diffusa Antennaria lanata Potentilla flabellifolia Sibbaldia procumbens Vaccinium deliciosum Microsteris gracilis Poa cusickii Ranunculus eschscholtzii Luzula spicata  B l a c k w a l l Meadow  23 days  Thalictrum occidentale Carex rossii Senecio integerrimus Hydrophyllum fendleri Lupinus latifolius Epilobium alpinum Potentilla diversifolia Festuca viridula Valeriana sitchensis Arenaria capillaris Castilleja miniata Penstemon procerus Pedicularis bracteosa Delphinium nuttallianum Erigeron peregrinus Veronica cusickii Castilleja parviflora Phleum alpinum Veratrum viride Carex spectabilis Agoseris aurantiaca Juncus drummondii Trisetum spicatum Elymus glaucus Arnica latifolia Hieracium gracile Sedum lanceolatum Arnica mollis Achillea millefolium Senecio triangularis Silene parryi  -|  10 APRIL  1  20  1 30  ~l  r20  10 MAY  31  1  «  1  '  '  1  '  20  30  10  20  31  10  10 JUNE  JULY  1  20  AUGUST  1 31  1  r  10  20  SEPTEMBER  71 be r e p r e s e n t e d  i n a complete phenodynamic s t r i p ( L i e t h 1 9 7 0 ) .  F i g u r e 111A-D c o n f i r m s the c a s u a l i m p r e s s i o n t h a t ,  within  a g i v e n p l a n t community, s p e c i e s f l o w e r i n g t i m e s form a sequence o f o v e r l a p p i n g i n t e r v a l s o r , more a c c u r a t e l y , o v e r l a p p i n g c u r v e s . Analogous p h e n o l o g i c a l g r a d i e n t s have been r e p o r t e d by Mowbray and O o s t i n g (1968) and Mosquin (1971). The average blooming p e r i o d l e n g t h f o r s p e c i e s o f the S a l t M a r s h , Wade's B o g , Ogg's Bog, and B l a c k w a l l Meadow i s 4-6, 32, 27, and 23 d a y s , r e s p e c t i v e l y . These l e n g t h s r e f l e c t b o t h the number o f s p e c i e s per community and t h e l e n g t h o f the growing season. The number o f angiospermous s p e c i e s i n each o f t h e s e s i t e s i s , i n o r d e r , 1 8 , 24, 30, and 45  showing an i n v e r s e  r e l a t i o n s h i p between the number o f s p e c i e s per community and t h e average l e n g t h o f a s p e c i e s ' blooming p e r i o d . The f i r s t t h r e e s i t e s a l l have about the same l o n g growing s e a s o n ; a p p r o x i m a t e l y a 5 1/2 month p e r i o d from t h e b e g i n n i n g o f A p r i l t o t h e m i d d l e o f September. B l a c k w a l l Meadow, on the  other  hand, has a growing season compressed i n t o 9-10 weeks from l a t e June to e a r l y September, a t l e a s t i n l a t e s n o w - l i e y e a r s , as were 1971 and 1972. The s h o r t growing s e a s o n , h i g h number o f s p e c i e s , d e n s i t y o f f l o w e r i n g i n d i v i d u a l s , and: percentage. .of . b i o t i c a l l y ;  p o l l i n a t e d s p e c i e s , and t h e consequent  significant interspecific  o v e r l a p o f f l o w e r i n g p e r i o d s i n t h e s u b a l p i n e meadow suggest t h a t meadow s p e c i e s have e v o l v e d i n an environment i n t e n s e l y c o m p e t i t i v e f o r a n i m a l ( e s p e c i a l l y i n s e c t ) p o l l i n a t o r s , much more so t h a n a s a l t marsh o r bog e n v i r o n m e n t . S e l e c t i o n i n such h i g h l y c o m p e t i t i v e c o n d i t i o n s would be f o r f l o r a l s p e c i a l i z a t i o n s  72 t h a t would i n c r e a s e a f l o w e r ' s a t t r a c t i v e n e s s  to animal p o l l i n -  a t o r s and t h e p o l l i n a t o r ' s c o n s t a n c y t o t h e f l o w e r .  There  c o u l d a l s o be s e l e c t i o n f o r autogamy ( c f . L e v i n 1972c')-, bu.i;at the expense o f l o n g term v a r i a b i l i t y . T h u s , t h e b r e a t h t a k i n g d i s p l a y o f showy f l o w e r s o f many f o r m s , c o l o r s , and odors t h a t is  c h a r a c t e r i s t i c o f l u s h s u b a l p i n e meadows i s l o g i c a l i n an  evolutionary context. One of  might i n t e r p r e t t h e l o n g e r average f l o w e r i n g  periods  the s a l t marsh s p e c i e s as a r e s u l t i n p a r t o f the "pre-  ponderance o f w i n d - p o l l i n a t e d s p e c i e s i n t h e marsh. T h e o r e t i c a l l y , a l o n g e r blooming season would be o f advantage t o an anemop h i l o u s s p e c i e s s i n c e wind i s a much l e s s r e l i a b l e p o l l i n a t i n g agent t h a n most a n i m a l s and a l o n g e r f l o w e r i n g p e r i o d would i n c r e a s e t h e chances o f s u c c e s s f u l p o l l i n a t i o n . However, c a l c u l a t i o n s r e v e a l no s i g n i f i c a n t d i f f e r e n c e , e i t h e r  within  one community o r over a l l c o m m u n i t i e s , between l e n g t h o f blooming t i m e s f o r anemophilous v s . entomophilous s p e c i e s . There i s , t h o u g h , a d e f i n i t e tendency f o r autogamous such as Drosera g.laucus  3  rotundifolia,  and Hordeum  Spergularia  brachy antherum  species  canadensis,  t o have s h o r t e r  Elymus than  average a n t h e s i s t i m e s , which i s what one would e x p e c t , autogamy ensures s u c c e s s f u l p o l l i n a t i o n .  since  73 E. P o l l i n a t i o n ecology.  The f o l l o w i n g summary o f the p o l l i n a t i o n e c o l o g y o f the study communities i s based on two summers o f f i e l d  observations  i n 1971 and 1972, and on o b s e r v a t i o n s and i n f e r e n c e s from the l a r g e l i t e r a t u r e on the s u b j e c t .  culled  D u r i n g the growing  season I v i s i t e d each o f the study areas u s u a l l y two o r t h r e e times a week t o study f l o r a l b i o l o g y and observe and c o l l e c t f l o w e r v i s i t o r s . Many a d d i t i o n a l o b s e r v a t i o n s were made w h i l e I was d o i n g the quadrat and t r a n s e c t  phytosociological  sampling on o t h e r o c c a s i o n s . Table 12 summarizes the o v e r a l l p o l l i n a t i o n scheme i n each o f the f o u r sample s i t e s . Each s p e c i e s has been c l a s s e d as b e i n g p o l l i n a t e d p r e d o m i n a n t l y by e i t h e r wind ( a n e m o p h i l y ) , insects  ( e n t o m o p h i l y ) , or b i r d s ( o r n i t h o p h i l y )  w a t e r - p o l l i n a t e d . The p o l l i n a t i o n mechanisms of- t h e  none are individual  s p e c i e s are d i s c u s s e d i n d e t a i l i n Appendix 3.  TABLE 12. Community mode o f p o l l i n a t i o n as p e r c e n t a g e o f the f l o r a and v e g e t a t i o n .  Pollination mechanism  Anemophily Entomophily Ornithophily  a  % flora/  S a l t Marsh  Wade's Bog  67%/83.4% 33/16.6  36/42.6 64/57.4  a  Ogg's Bog  40/48.2 60/51.8  Blackwall Meadow  25/25 72.7/74.4 2.3/0.6  % v e g e t a t i o n (determined from importance v a l u e s ) .  74 C l e a r l y , anemophily i s the major mode o f p o l l i n a t i o n i n the s a l t marsh. E n t o m o p h i l y predominates  i n the  subalpine  meadow, w h i l e b o t h bogs have more of a b a l a n c e between  insect  and wind p o l l i n a t i o n . The s i t u a t i o n i n the s a l t marsh i s  not  as c l e a r - c u t as i t seems, however. D u r i n g b o t h summers o f f i e l d work I have observed bumble bee (Bombus  terricola  Grne. ) p o l l e n f o r a g i n g on s i x t y p i c a l l y  dentalis  s a l t marsh s p e c i e s : D e s o h a m p s i a littoralis,  Agrostis exarata,  and Salioornia In  anemophilous  oespitosa, Festuoa  Plantago  maritima,  occi-  var.  rubra  Junous b a l t i o u s ,  ( P o j a r 1973b).  virginica  g e n e r a l , bumble bees are the most i m p o r t a n t a n i m a l  p o l l i n a t i n g v e c t o r at a l l f o u r s i t e s .  D i p t e r a are  extremely  i m p o r t a n t , p a r t i c u l a r l y S y r p h i d a e , M u s c i d a e , and B o m b y l i d a e . Lepidoptera, especially b u t t e r f l i e s  and s k i p p e r s  (Rhopalocera),  are a l s o o f major s i g n i f i c a n c e i n the s u b a l p i n e meadow, but is  s t r a n g e t h a t t h e r e are v e r y few b u t t e r f l i e s  i n the  it  Tofino  area. I t i s a l s o noteworthy t h a t none of t h e nine (.Puccinellia  pumila,  braohyantherum, glaucus,  prooumbens)  Spergularia canadensis  Drosera  Epilobium  rotundifolia  alpinum,  (Fig.  113),  Miorosteris gracilis,  t h a t are f u l l y o r p r e d o m i n a n t l y  (self-pollinating)  (Fig.  are dominant elements  species 112),  Hordeum  Elymus and S i b b a l d i a  autogamous  i n t h e i r communities.  From q u a l i t a t i v e e s t i m a t e s o f p o l l i n a t o r d e n s i t y and a c t i v i t y I f e e l t h a t i n a l l o f t h e s e communities t h e  insects  are the l i m i t i n g f a c t o r i n the r e p r o d u c t i o n o f many entomophilous species.  That i s , I b e l i e v e t h a t t h e r e i s c o m p e t i t i o n  among f l o w e r s f o r p o l l i n a t o r s r a t h e r t h a n among i n s e c t s  for  75a,  Fig.  112. Spergularia  canadensis;  p o l l i n a t i n g flower.  chasmogamous, s e l f I n d i v i d u a l p l a n t s o f t e n have  b o t h chasmogamous and c l e i s t o g a m o u s f l o w e r s .  Fig.  113. Drosera-rotundpfoli'a;  s h o r t - l i v e d , . chasmogamous ,  s e l f - p o l l i n a t i n g f l o w e r . Two c l e i s t o g a m o u s f l o w e r s can  be seen j u s t above the open f l o w e r .  76 n e c t a r and p o l l e n . T h i s seems p a r t i c u l a r l y t r u e i n B l a c k w a l l Meadow, w h i c h has a l a r g e number o f entomophilous  species  and  an e x t r e m e l y h i g h d e n s i t y o f s i m u l t a n e o u s l y - b l o o m i n g  flowers  (see F i g s .  least  6 8 7 ) . Mosquin (1971)  concluded t h a t , at  d u r i n g midsummer, the f l o r a o f a mountain v a l l e y near Banff competed s t r o n g l y f o r p o l l i n a t o r s , and some s p e c i e s unsuccessful  were  i n the c o m p e t i t i o n . H o c k i n g (19 68) and Kevan (1970,  1972) have noted a r e l i a n c e o f f l o w e r s on p o l l i n a t i n g in  high a r c t i c vegetation,  insects  w h i c h , i n d e n s i t y and showiness of  f l o w e r s and compressed growing s e a s o n , i s somewhat s u b a l p i n e meadow v e g e t a t i o n .  Undoubtedly,  s i m i l a r to  interspecific  c o m p e t i t i o n has p l a y e d a major r o l e i n the e v o l u t i o n o f showy flowers, of  as w e l l as p r e s s u r i n g  autogamy  some s p e c i e s  i n t o the  escapism  ( L e v i n 197 2 c ) .  A n o t h e r p o s s i b l e advantage o f the showy f l o w e r s o f some subalpine  s p e c i e s has been suggested by H o c k i n g and S h a r p l i n  (1965) and Kevan ( 1 9 7 0 ) . They have found t h a t the  intrafloral  temperatures o f l a r g e showy f l o w e r s are g e n e r a l l y above ambient  i n the a r c t i c , and under optimum c o n d i t i o n s  the  the  temperatures i n f l o w e r s shaped l i k e p a r a b o l i c r e f l e c t o r s  can  exceed t h e ambient by 5 ° ' t o 1 0 ° C ( B l i s s 1971). I n B l a c k w a l l Meadow, bowl-shaped f l o w e r s l i k e t h o s e o f Potentilla folia,  P. f l a b e l l i f o l i a ( F i g .  and Anemone  occidentalis  114)., R a n u n c u l u s  diversieschscholtzii  serve as b a s k i n g s i t e s f o r the  3  various  d i p t e r a n s t h a t a r e the p r i n c i p a l p o l l i n a t o r s o f t h e s e  species.  T h i s f l o w e r b a s k i n g i s p r o b a b l y most i m p o r t a n t  insects  d u r i n g e a r l y morning i n the m o u n t a i n s , the a i r temperature s t i l l  t o the  when the sun i s up but  l o w . Kevan (197 0) has suggested t h a t  77  Fig.  114. Potentilla  Slightly  flabellifolia.  protogynous  f l o w e r ; n e c t a r s e c r e t e d as a t h i n , s h i n i n g on  the b l a c k i s h - p u r p l e d i s c j u s t i n s i d e  the  f i l a m e n t b a s e s . Bowl-shaped b l o s s o m r s e r v e s basking s i t e  Fig.  115. Plantago  for  maritima.  as  insects.  Strongly protogynous,  p h i l o u s flowers, borne i n a d e n s e ,  anemo-  acropetally-  f l o w e r i n g s p i k e . Note the e l o n g a t e stigmas well-exserted,  film  versatile  anthers.  and  78 the h i g h e r i n t r a f l o r a l t e m p e r a t u r e s i n g e n e r a l may a l s o be important seed  f o r p o l l e n tube g r o w t h , f e r t i l i z a t i o n , and p o s s i b l y  development. A t h e o r e t i c a l aspect of i n t e r s p e c i f i c competition  for  p o l l i n a t o r s has been e x p l o r e d i n models by L e v i n and Anderson (1970) and Straw ( 1 9 7 2 ) . Both models have e s s e n t i a l l y the same i n i t i a l assumptions: flowering,  (1) two randomly i n t e r m i x e d ,  self-incompatible species with flowers  s i m i l a r t o a t t r a c t the same p o l l i n a t o r s ;  simultaneously sufficiently  (2) a s i n g l e  p o l l i n a t o r species to s e r v i c e both p l a n t s p e c i e s ;  (3) a d e f i c i t  o f p o l l i n a t o r s r e l a t i v e t o the number of f l o w e r s . Then, i f  the  r a t e o f r e p r o d u c t i o n o f each f l o w e r s p e c i e s ' d e p e n d s on i t s success i n the c o m p e t i t i o n f o r p o l l i n a t o r s , the frequency  of a  species  the  i n subsequent g e n e r a t i o n s w i l l be p r o p o r t i o n a l t o  degree o f p o l l i n a t o r constancy t o t h a t s p e c i e s , and the favored species  e v e n t u a l l y s h o u l d be e l i m i n a t e d .  constancy i s d e n s i t y dependent ( c f .  less  If pollinator  L e v i n and K e r s t e r  1969a),  the m i n o r i t y s p e c i e s w i l l be at an i n c r e a s e d d i s a d v a n t a g e and i t s c o m p e t i t i v e e x c l u s i o n s h o u l d be a c c e l e r a t e d  (Straw  The f i r s t two r e q u i r e m e n t s f o r t h i s type o f exclusion rarely,  1972).  competitive  i f a t a l l , e x i s t i n n a t u r e ( C r o s s w h i t e and  C r o s s w h i t e 19 7 0 ; ; M a c i o r " 1971; Straw 1972). In t h e c o m m u n i t i e s , assumption  study  (3) seems t o be v a l i d , e s p e c i a l l y  for  the s u b a l p i n e meadow. I n the meadow, t h e r e are two s p e c i e s Arnica  triangularis, all  latifolia  vs.  A. m o l l i s  and S e n e c i o  integerrimus  vs.  pairs, S.  t h a t have s i m i l a r f l o w e r s and p o l l i n a t o r s and  s e l f - i n c o m p a t i b l e . However, they do not r e l y on a s i n g l e  p o l l i n a t o r s p e c i e s but r a t h e r are s e r v i c e d by a v a r i e t y o f  are  79 Hymenoptera, D i p t e r a , and L e p i d o p t e r a ; they are " c o r n u c o p i a n " f l o w e r s i n the sense o f Mosquin ( 1 9 7 1 ) . Nor are t h e s e s p e c i e s randomly i n t e r m i x e d  Arnica  mollis  and S e n e c i o  integerrimus  g e n e r a l l y o c c u r on d r i e r s i t e s w i t h i n the meadow than t h e i r congeners. F u r t h e r m o r e , S. integerrimus in  f l o w e r s much e a r l i e r  the season t h a n t h e o t h e r t h r e e s p e c i e s , which a r e more o r  l e s s s i m u l t a n e o u s l y l a t e - f l o w e r i n g . I n t h e study c o m m u n i t i e s , t h e s e s p e c i e s p a i r s are t h e c l o s e s t approaches t o the t h e o r e t i c a l a s s u m p t i o n s , and c l e a r l y the approaches are q u i t e remote. N e v e r t h e l e s s , i t i s safe t o say t h a t avoidance o f i n t e r s p e c i f i c c o m p e t i t i o n f o r p o l l i n a t o r s , by s h i f t i n g of f l o w e r i n g p e r i o d a n d / o r h a b i t a t p r e f e r e n c e a n d / o r p o l l i n a t i n g a g e n t , has been i n s t r u m e n t a l i n the e v o l u t i o n of p l a n t s p e c i e s i n g e n e r a l . I n p a r t i c u l a r , i t i s r e f l e c t e d i n the s p a t i a l d i s t r i b u t i o n s and phenology o f the s p e c i e s o f the s t u d y a r e a s , and moreover i s much more apparent  and presumably p l a y s a much more i m p o r t a n t  r o l e i n the s u b a l p i n e meadow t h a n i n the s a l t marsh or bogs.  Types o f p o l l i n a t i o n  Gross f l o r a l morphology s h o u l d be r e g a r d e d as r e s u l t i n g from a d a p t a t i o n s f o r f e r t i l i z a t i o n from f l o w e r s o f d i f f e r e n t i n d i v i d u a l s of t h e same s p e c i e s  (Darwin 1876, 1877; Whitehouse  1 9 5 9 ) . The e x c e p t i o n s t o t h i s g e n e r a l r u l e ( e g . , as o c c u r i n self-fertilizing adaptations  s p e c i e s ) are g e n e r a l l y r e g a r d e d as  f o r t h e sake o f g r e a t e r  secondary  c e r t a i n t y o f seed  p r o d u c t i o n o f a more or l e s s u n i f o r m genotype ( S t e b b i n s 19 50, 1957a; Grant 19 71)...The .adaptive n a t u r e . o f t h e ' f l o w e r must be  80  appreciated  i n a d i s c u s s i o n o f p o l l i n a t i o n e c o l o g y , but  temptation to speculate  on the a d a p t i v e f u n c t i o n s  f l o r a l s t r u c t u r e s t h a t defy l o g i c a l e v o l u t i o n a r y s h o u l d be  the  of various interpretation  resisted.  The i n t e r p r e t a t i o n  o f t h e f l o w e r as a f u n c t i o n a l  r e p r o d u c t i v e u n i t has l e d t o the d e s c r i p t i o n o f m o r p h o l o g i c a l categories ecology  f o r f l o w e r forms r e l a t e d t o t h e i r p o l l i n a t i o n t h u s , we have "bee f l o w e r s " , " f l y f l o w e r s " ,  f l o w e r s " , and the l i k e .  C r o s s w h i t e and C r o s s w h i t e (1966)  "beetle and  M a c i o r (1971) have p o i n t e d out t h e danger o f such a t y p o l o g i c a l a p p r o a c h , f o r many p l a n t s p e c i e s u t i l i z e a wide v a r i e t y o f p o l l i n a t o r s and are not r e s t r i c t e d  t o one p a r t i c u l a r  T h i s danger s h o u l d be kept i n mind d u r i n g the  following  d i s c u s s i o n , s i n c e I s h a l l be r e f e r r i n g t o "bumble bee etc.,  vector.  w h i l e o u t l i n i n g the p o l l i n a t i o n mechanisms  flowers",  characteristic  of c e r t a i n types of blossoms. C e r t a i n combinations of positively correlated  c h a r a c t e r s o r f e a t u r e s make up a p a r t i c u l a r  syndrome ( F a e g r i and van der P i j l  19 71) c o r r e s p o n d i n g t o each  of the f o l l o w i n g p o l l i n a t i o n s t r a t e g i e s . The o u t l i n e i s o f F a e g r i and van der P i j l  that  ( 1 9 7 1 ) ; t h e examples are from the  study communities.  Anemophily  Wind p o l l i n a t i o n o r anemophily i s t h e dominant type o f abiotic pollination in plants,  and i s the o n l y type t h a t  occurs  i n the study c o m m u n i t i e s , t h e r e b e i n g no w a t e r - p o l l i n a t e d species.  The syndrome o f anemophily i n c l u d e s the  following  81 features  (Whitehead 19 69; F a e g r i and van der P i j l  19 7 1 ; P r o c t o r  and Yeo 1973): the f l o w e r s t e n d t o be o f s m a l l s i z e , reduced and i n c o n s p i c u o u s , t o l a c k n e c t a r  and o d o r , and t o be c l u s t e r e d  i n dense i n f l o r e s c e n c e s ; the a n t h e r s have abundant, l i g h t , dry p o l l e n , and the stigmas have an expanded s u r f a c e a r e a . Anemop h i l o u s s p e c i e s are f r e q u e n t l y u n i s e x u a l , perhaps because  self-  p o l l i n a t i o n i n an h e r m a p h r o d i t i c , w i n d - p o l l i n a t e d f l o w e r would be i n e v i t a b l e w i t h such a h i g h i n c i d e n c e o f p o l l e n per  unit  a r e a i n t h e immediate v i c i n i t y o f t h e a n t h e r s ( F a e g r i and van der P i j l  1971). Then t o o , when p o l l e n i s t h e i n s e c t  attractant,  the e v o l u t i o n o f u n i s e x u a l f l o w e r s s h o u l d tend toward anemop h i l y , s i n c e entomophilous p l a n t s would s u f f e r a r e d u c t i o n i n t h e number o f i n s e c t v i s i t s t o female f l o w e r s ( K a p l a n and Mulcahy 1971). U n i s e x u a l f l o w e r s are found i n such w i n d p o l l i n a t e d s p e c i e s as  and Thalictrum  M y r i c a g a l e , Empetrum  nigrum,  C a r e x spp.,  I f an anemophilous s p e c i e s  occidentale.  has  h e r m a p h r o d i t i c f l o w e r s , t h e s e are f r e q u e n t l y s t r o n g l y dichogamous eg.,  Plantago maritima  virginica (Fig.  117),  (Fig.  116a  (Fig.  S b),  115)  and P. m a c r o c a r p a ,  Triglochin  L u z u l a s p p . , and S c i r p u s  The genus Thalictrum  maritimum, cespitosus  Salicornia  J u n c u s spp. (Fig.  118).  p r o v i d e s e x c e l l e n t examples o f t h e s e  trends.  K a p l a n and Mulcahy (19 71) showed t h a t the d i o e c i o u s and p o l y gamous s p e c i e s o f Thalictrum  are i n g e n e r a l the most anemo-  p h i l o u s , w h i l e hermaphrodite  s p e c i e s are the most e n t o m o p h i l o u s .  F u r t h e r m o r e , the hermaphrodite Thalictrum gamous ( F a e g r i and van der P i j l  s p e c i e s are d i c h o -  1 9 7 1 ) . F i n a l l y , as an e c o l o g i c a l  c o r o l l a r y , wind p o l l i n a t i o n most o f t e n predominates  i n open  v e g e t a t i o n w i t h clumped s p e c i e s d i s t r i b u t i o n s (Whitehead 19 6 9 ) .  CO  Fig.  116a. S a l i c o r n i a  virginica;  protogynous  F i g - 116b. S a l i c o r n i a  virginica;  f l o w e r s , here i n female stage  i n male stage  (stigmas r e c e p t i v e ) .  exserted,  flowers  (anthers  shedding p o l l e n ) .  CO CO  8  Fig.  117. J u n o u s  baltious;  protogynous, flowers.  strongly  anemophilous  F i g . 118  Seivpus  oespitosus  anemophilous  ; strongly  protogynous,  flowers united i n a s e v e r a l -  flowered, s o l i t a r y , terminal  spikelet.  Male stage i n m i d - f o r e g r o u n d ;  female  stage b e h i n d and t o the  left.  84 Most of the s a l t marsh s p e c i e s are e x c e l l e n t examples o f a n e m o p h i l e s , and the marsh i t s e l f  i s a predominantly wind-  p o l l i n a t e d community. However-, as mentioned b e f o r e ,  six  :  t y p i c a l l y anemophilous s a l t marsh s p e c i e s are a l s o v i s i t e d by p o l l e n - f o r a g i n g bumble b e e s . P o j a r (1973b) has d i s c u s s e d possible significance of t h i s fortuitous  e n t o m o p h i l y . The  s i t u a t i o n i s advantageous  since:the  t o the p l a n t s ,  the  efficiency  of wind p o l l i n a t i o n must be c o n s i d e r a b l y reduced i n the humid o c e a n i c c l i m a t e o f the T o f i n o a r e a . The bumble bees seem t o have responded t o a p a u c i t y o f p o l l e n - r i c h entomophilous  flowers  by s h i f t i n g t h e i r p o l l e n - g a t h e r i n g a c t i v i t i e s t o s p e c i e s  that,  i n most o t h e r c i r c u m s t a n c e s , would be i g n o r e d . Anemophily i s now g e n e r a l l y c o n s i d e r e d t o be a d e r i v e d c o n d i t i o n i n angiosperms  (Whitehead 1969; K u g l e r 1970;  1970a; F a e g r i and van der P i j l  Stebbins  1971). Apparent r e v e r s i o n s  from  wind p o l l i n a t i o n t o secondary e n t o m o p h i l y have o c c u r r e d i n the t r o p i c a l sedge Dichromena  oiliata  certain t r o p i c a l r a i n forest 1 9 7 1 ) , i n r ' t h e geniis -.Salix,  ( L e p p i k 1955; Baker 1 9 6 3 ) , i n  g r a s s e s (Soderstrom and C a l d e r o n  and e x t e n s i v e l y i n the  family  Moraceae ( S t e b b i n s 1970a). Other o b s e r v e r s have noted p o l l e n f o r a g i n g v i s i t s by honey bees (Bogdan 19 62) and hover (Clifford lanceolata  1964) t o g r a s s f l o w e r s , and by honey bees t o (Clifford  In c o n t r a s t ,  Plantago  1962).  adaptive s h i f t s  from i n s e c t to wind p o l l i n a t i o n  are a l s o apparent i n some groups. The genera Plantago Thalictrum  flies  and  both c o n t a i n i n s e c t - and w i n d - p o l l i n a t e d s p e c i e s ,  and the anemophily e v i d e n t l y i s d e r i v e d and o f f a i r l y o r i g i n ( S t e b b i n s - 1 9 7 0 a ; F a e g r i and van der P i j l  recent  1971; K a p l a n  85 and Mulcahy 1 9 7 1 ) . I n the s t u d y communties, Plantago P.  all  macrocarpa,  and T h a l i c t r u m  oocidentale  (Fig.  p r e d o m i n a n t l y w i n d - p o l l i n a t e d . Thalictrum  and Sanguisorba  maritima,  119a & b)  (Ranunculaceae)  (Rosaceae) are two genera t h a t b e l o n g t o o v e r -  w h e l m i n g l y entomophilous f a m i l i e s , but n e v e r t h e l e s s some anemophilous s p e c i e s Sanguisorba  are  contain  (Knuth 1906-1909; S t e b b i n s  1970a).  ( F i g . 1 2 0 ) , a t a l l p e r e n n i a l herb o f  officinalis  the sphagnum b o g s , has a p e t a l o u s t h e f l o w e r s are aggregated  f l o w e r s w i t h l o b e d stigmas and  i n a dense i n f l o r e s c e n c e . But t h e  deep maroon-purple f l o w e r s are markedly n e c t a r i f e r o u s ,  have  s t i c k y (not powdery) orange p o l l e n , and are p o l l i n a t e d by dipterans.  represents a condition intermediate  S. officinalis  between anemophily and e n t o m o p h i l y , and t h e d i r e c t i o n o f the a d a p t i v e s h i f t can o n l y be presumed, a l t h o u g h the m a j o r i t y o f Sanguisorba  s p e c i e s are w i n d - p o l l i n a t e d ( S t e b b i n s  Fly  1970a).  p o l l i n a t i o n (myophily)  There i s g r e a t v a r i a t i o n i n the p o l l i n a t i o n  methods  employed by D i p t e r a . There are many u n s p e c i a l i z e d f l i e s ,  of  s m a l l s i z e and w i t h s h o r t p r o b o s c e s , t h a t are g e n e r a l l y r e s t r i c t e d - , t o more " p r i m i t i v e " f l o w e r s w i t h e a s i l y a c c e s s i b l e nectar.  Blossoms c h a r a c t e r i s t i c a l l y p o l l i n a t e d by t h e s e s m a l l ,  unspecialized f l i e s  form a f a i r l y d i s t i n c t type o f f l y f l o w e r ,  a l t h o u g h they are a l s o v i s i t e d by many s m a l l  hymenopterans  ( K u g l e r 1955). The syndrome o f t h i s type of myophily i n c l u d e s r e g u l a r , s i m p l e , g e n e r a l l y l i g h t but d u l l - c o l o r e d f l o w e r s w i t h l i t t l e or no depth e f f e c t .  The n e c t a r i s v e r y a c c e s s i b l e ,  the  oo  CD  Fig.  119a. Thalictvum  occidentale  . Male  F i g . 119b. Thaliotrum  flowers.  occidentale.  f l o w e r s (stigmas withered).  T h i s i s a d i o e c i o u s , anemophilous s p e c i e s . the e l o n g a t e  s t i g m a s , the e l o n g a t e ,  Note  pendent  stamens, and the r e d u c e d , i n c o n s p i c u o u s f l o w e r s w h i c h are a p e t a l o u s , sepals  with greenish-white,  ( f a l l e n o f f i n female f l o w e r s ) .  caducous  already  Female  87a,  Fig.  120. S a n g u i s o r b a . o f f i o i n a l i s ; flowers  apetalous,  maroon t o deep maroon p u r p l e ; the s t i c k y , pollen  Fig.  sepals  orange  i s o f t e n shed i n bud.  121. T r i e n t a l i s  arctioa;  the white p e t a l s form a  s h a l l o w l y bowl-shaped  s t a r ; the t h i c k ,  fleshy,  stamen-bearing r i n g i s a t t r a c t i v e t o f l i e s .  <rrb  88 f l o w e r s have no s t r o n g o d o r , and t h e s e x u a l organs are  well-  exposed. Examples are t h e f l o w e r s o f Potentilla  flabellifolia  (Fig.  114),  Trientalis  arotioa  Coptis. a s p l e n i f o l i a  and  (Fig.  In the  viride  123).  (Fig.  121),  C. t r i f o l i a ( F i g .  Stellaria 122),  and  s a l t marsh, P o t e n t i l l a  humifusa, Veratrum  paoifioa  is  p o l l i n a t e d p r i m a r i l y by bumble bees and bee f l i e s , w h i l e t h e s u b a l p i n e meadow s p e c i e s P. diversifolia  and P.  flabellifolia  are v i s i t e d o n l y r a r e l y by bumble bees ( s m a l l f l i e s and s y r p h i d s are t h e i r most f r e q u e n t b e s i d e s Trifolium  p o l l i n a t o r s ) . Potentilla  wormskgoldii  is,  paoifioa  , t h e o n l y showy f l o w e r i n t h e  s a l t marsh. I n t h e s u b a l p i n e meadow t h e r e are many showy entomophilous  ( i n c l u d i n g bombophilous) f l o w e r s . S i n c e t h e  f l o w e r s of a l l t h r e e Potentilla difference of  species  are v e r y s i m i l a r , the  i n p o l l i n a t o r s i s p r o b a b l y due i n p a r t t o a s h i f t i n g  the bumble b e e s ' and bee f l i e s '  a t t e n t i o n s t o more h i g h l y  s p e c i a l i z e d , more r e w a r d i n g f l o w e r s as an o p t i m a l e f f i c i e n c y response t o p o l l i n a t o r c o m p e t i t i o n i n the s u b a l p i n e meadow.  In  the s a l t marsh, the i n s e c t s have t o t a k e whatever i s a v a i l a b l e , w h i l e i n the  s u b a l p i n e meadow t h e r e i s a w e a l t h o f f l o w e r s  to  choose from. A different flies  type o f f l y . f l o w e r  (sapromyophilous)  ( u s u a l l y c a r r i o n - and d u n g - f l i e s ) w i t h f o u l  resembling that of decaying p r o t e i n .  attracts  odors  Sapromyophilous blossoms  are g e n e r a l l y r a d i a l and f r e q u e n t l y the p e r i a n t h p a r t s have f i l i f o r m h a i r s o r o t h e r appendages ( e g . , Menyanthes D u l l , p u r p l i s h or b r o w n i s h f l o r a l  c o l o r s are o f t e n found i n  a s s o c i a t i o n w i t h t h e odor o f p u t r e f a c t i o n . myophilous s p e c i e s  trifoliata).  Examples o f  i n the study communities are  saproNephrophyllidium  89cv  Fig.  122. Coptis  trifolia.  The s e p a l s are w h i t e and  p e t a l o i d , w h i l e the p e t a l s are about h a l f  the  l e n g t h o f the s e p a l s , f l e s h y , h o l l o w e d and n e c t a r i f e r o u s at the t i p s , and shaped  like  t h i c k , woolen m i t t e n s .  Fig.  12 3. Veratrum  viride.  Weakly p r o t a n d r o u s f l o w e r s  w i t h y e l l o w - g r e e n t o deep green t e p a l s have n e c t a r i e s at t h e i r b a s e s .  that  90 orista-galli  Lysiahitum  3  perhaps Sanguisorba  americanum  3  Antennaria  A l l o f t h e s e s p e c i e s have  officinalis.  f l o w e r s t h a t f i t the syndrome i n some, but not a l l , Nephrophyllidium tubular, lobes.  particulars  ( F i g . 124) has w h i t e ,  orista-galli  copiously nectariferous  short-  flowers with fringed  The f l o w e r s have (to me) a s t r o n g  l a u n d r y and the p e t a l s d e l i q u e s c e The f l o w e r s are v i s i t e d  and  lanata,  corolla  sour odor of mildewed  w i t h i n a few days o f a n t h e s i s  enthusiastically  muscid f l i e s . The f l o w e r of Lysiahitum  by l a r g e and s m a l l ( F i g . 125)  amerioanum  emits a p o w e r f u l skunky o d o r , and f l i e s as w e l l as numerous bugs and b e e t l e s are a t t r a c t e d t o the b r i g h t y e l l o w spathes and f l e s h y , g r e e n i s h - y e l l o w s p a d i c e s , o f t e n c r a w l i n g about f l o w e r s by the hundreds. Antennaria has d i r t y g r e e n i s h - w h i t e ,  lanata,  the  a dioecious  strongly nectariferous  species  flowers  that  s m e l l o f bad cheese or d i r t y s o c k s . The f l o w e r s are v i s i t e d by s m a l l muscid f l i e s and o c c a s i o n a l l y by s y r p h i d s . maroon-purple, officinalis  highly nectariferous  The deep  flowers of  Sanguisorba  ( F i g . 120) are p o l l i n a t e d by s m a l l muscid f l i e s ,  m a i n l y . The p u r p l i s h c o l o r suggests t h a t the f l o w e r s  should  a l s o have a f o u l s m e l l , but I c o u l d d e t e c t none. The w a s p - l i k e S y r p h i d a e or h o v e r f l i e s Diptera.  Veronica  cusickii  (Fig.  126)  and  are more s p e c i a l i z e d V. w o r m s k j o l d i i  are  two s p e c i e s i n B l a c k w a l l Meadow t h a t seem to be p o l l i n a t e d almost e x c l u s i v e l y by s y r p h i d s  (cf.  P r o c t o r and Yeo 197 3 ) .  The b l u e - v i o l e t f l o w e r s o f b o t h s p e c i e s are q u i t e  similar,  w i t h a s h o r t c o r o l l a tube t h a t s t o r e s and c o n c e a l s  nectar  s e c r e t e d by a d i s c below the o v a r y . The c o n s p i c u o u s l y  exserted  s t y l e i s d i r e c t e d o b l i q u e l y downward, and the two stamens  91o/  Fig.  124. Nephrophyllidium  orista-galli,  a distylous  A l o n g - s t y l e d f l o w e r i s p i c t u r e d h e r e . Note  species. the  c o p i o u s n e c t a r and t h e e r o s e - u n d u l a t e membranes on  Fig.  the margins and midnerves o f the c o r o l l a l o b e s .  125. Lysichitum  ameriaanum  has m e p h i t i c f l o w e r s w i t h a  t h i c k f l e s h y s p a d i x subtended by a b r i g h t y e l l o w spathe.  ID  Fig.  126.  Veronica  cusickii.  Note t h e  clean,  F i g . 127.  Valeriana  sitchensis  has  short-  spare l i n e s o f t h e f l o r a l  t u b u l a r f l o w e r s aggregated i n  architecture.  heads.  93  d i v e r g e l a t e r a l l y . As Knuth (19 06-19 09) p o i n t s o u t , t h e  flowers  are a d m i r a b l y s u i t e d f o r v i s i t s from h o v e r f l i e s t h a t , i n a l i g h t i n g on t h e lower c o r o l l a l o b e , f i r s t t o u c h the with t h e i r ventral surfaces.  stigma  As the h o v e r f l y s e t t l e s , i t  seizes  the t h i n bases o f t h e f i l a m e n t s , drawing them t o g e t h e r and dusting i t s underside w i t h a fresh load of p o l l e n . Bombylidae or bee f l i e s are h i g h l y s p e c i a l i z e d D i p t e r a and most o f the s p e c i e s have l o n g , s l e n d e r , r i g i d  probosces  s u i t e d f o r nectar feeding at l a r g e , t u b u l a r flowers  (Proctor  and Yeo 1973). Bee f l i . e s are common p o l l i n a t o r s o f  Valeriana  sitohensis  ( F i g . 127) and t h e showy-flowered Compositae  ATpargidium"-  b.ore  and-both o f the  (Fig.-vl28 ) ,  ale., Arnica  and  Senecio  Erigeron  like  ( F i g . 129),  peregrinus  species t h a t occur i n  B l a c k w a l l Meadow. These s p e c i e s a l l have heads o f  short-tubular  f l o w e r s . They a l l produce so.-".much n e c t a r t h a t i t r i s e s t o  the  top o f the f l o r a l tube and i s thus a c c e s s i b l e t o b o t h l o n g and s h o r t - t o n g u e d  insects.  P r e d i c t a b l y , t h e f l o w e r s are v i s i t e d  by a wide range o f i n s e c t p o l l i n a t o r s : bumble b e e s , bee short-tongued  flies,  hoverflies,  s m a l l muscid f l i e s ,  b e e s , and  butterflies  and s k i p p e r s . An a d a p t i v e a s p e c t o f such a spectrum  o f p o l l i n a t o r s i s the l i k e l i h o o d t h a t b e t w e e n - p l a n t w i l l be encouraged and o u t c r o s s i n g thus promoted. insects  flights  Individual  tend t o v i s i t a l l o f the r e w a r d i n g f l o w e r s w i t h i n a  p a r t i c u l a r head b e f o r e f l y i n g on to a n o t h e r head. A l a r g e number and v a r i e t y o f p o l l i n a t o r s would d e c r e a s e the  average  number o f r e w a r d i n g f l o w e r s pea?.""head and f o r c e i n s e c t s v i s i t more p l a n t s .  T h i s would be a r e a l advantage t o  w i t h aggregated f l o w e r s , e s p e c i a l l y those t h a t , l i k e  to species Valeriana  94c  Fig.  128.  Apargidium  The f l o w e r s are a l l l i g u l a t e  boreale.  and zygomorphic, and the head or c a p i t u l u m i s c a p i t a t e (see  Fig.  129.  Erigeron  Leppik  peregrinus.  are s t e r e o m o r p h i c ,  1960).  The y e l l o w - o r a n g e d i s c  flowers  the l i g h t p i n k r a y f l o w e r s  zygomorphic, and the c a p i t u l u m i s  are  actinomorphic.  sitchensis,  are s e l f - c o m p a t i b l e and s u s c e p t i b l e  to  95 geitonogamy  ( s u c c e s s f u l p o l l i n a t i o n between two f l o w e r s on the same p l a n t ) .  Ant p o l l i n a t i o n (myrmecophily)  Ants (Hymenoptera, F o r m i c i d a e ) are n e a r - u b i q u i t o u s frequently  insects  found i n the v i c i n i t y o f f l o w e r s , but are more than  l i k e l y n e c t a r t h i e v e s r a t h e r than l e g i t i m a t e p o l l i n a t o r s  (Faegri  and van d e r P i j l  are  19 7 1 ; P r o c t o r and Yeo 197 3 ) . S i n c e ants  u s u a l l y s m a l l and have smooth, h a r d b o d i e s , they are p o o r l y s u i t e d f o r p i c k i n g up and t r a n s p o r t i n g p o l l e n . True myrmecophily is  difficult  Glaux  maritima  t o e s t a b l i s h , but I have seen ants p o l l i n a t i n g ( F i g . 130) i n the s a l t marsh, and i n t h i s am  c o r r o b o r a t e d by s i m i l a r o b s e r v a t i o n s i n F a e g r i . „ a n d van der P i j l  by D a h l and Hadac  (reported  1971) i n Norway.  Bumble bee p o l l i n a t i o n (bombophily)  Bumble bees (Hymenoptera, Bombidae, Bombus) few  i n s e c t s w i t h the s i z e , s t r e n g t h ,  are among the  and i n t e l l i g e n c e  to  u t i l i z e the most c o m p l i c a t e d bee f l o w e r s . T h e i r s t r e n g t h  and  the l e n g t h o f t h e i r mouthparts enable them t o t a k e n e c t a r t h a t is  g e n e r a l l y c o n c e a l e d i n f l o r a l tubes o r spurs and  often  b a r r i c a d e d by f l o r a l p a r t s t h a t must be pushed a s i d e t o g a i n the n e c t a r . H i g h l y s p e c i a l i z e d bumble bee f l o w e r s tend t o be zygomorphic w i t h g r e a t depth e f f e c t , w i t h good l a n d i n g p l a t f o r m s .  and m e c h a n i c a l l y s t r o n g  Flower c o l o r i s g e n e r a l l y  y e l l o w o r b l u e , and v i s u a l or m e c h a n i c a l n e c t a r guides  bright are  96<v  Fig.  130. Glaux  maritima.  A l o w - g r o w i n g s a l t marsh  w i t h s m a l l , w h i t e , myrmecophilous  Fig.  131. Delphinium the  nuttallianum.  flowers.  Bombophilous f l o w e r s .  zygomorphy, deep b l u e c o l o r , l a n d i n g  and n e c t a r spur o f the  species  flower.  Note  platform,  97  o f t e n p r e s e n t . N e c t a r and s e x u a l organs u s u a l l y are  well  c o n c e a l e d and f l o w e r odors are f r e s h and sweet.  T y p i c a l bumble  bee f l o w e r s i n t h i s i n v e s t i g a t i o n are Delphinium  nuttallianum,  Lupinus  wormskjoldii,  latifolius,  Pedicularis  Gentiana  Delphinium,  Gentiana,  flowers with f a i r l y spurs.  and  bracteosa,  Delphinium  sceptrum,  Trifolium  var.  Castilleja  parviflora  Trifolium,  and Castilleja  albida.  a l l have  l o n g n e c t a r - c o n t a i n i n g f l o r a l tubes o r  nuttalli'anum  ( F i g . 131) has a s i n g l e spur up  t o 2 0 mm l o n g i n each deep b l u e f l o w e r . The spur i s formed from processes  o f the two upper p e t a l s and i s e n c l o s e d i n the  s e p a l , which i s i t s e l f  s p u r r e d . The a n t e r i o r ,  upper  upwardly-flared  p a r t s o f the two upper p e t a l s bar the e n t r a n c e t o the spur a n d , t o g e t h e r w i t h the s p u r ' s insects. of  l e n g t h , deny access to  short-tongued  F u r t h e r d e s c r i p t i o n o f the i n t r i c a t e f l o r a l mechanism can be found i n Appendix 3.  D. nuttallianum Gentiana  sceptrum  has l a r g e , d e e p - t u b u l a r ,  blue  (often  s t r e a k e d or m o t t l e d w i t h g r e e n , e s p e c i a l l y i n s i d e ) f l o w e r s t h a t s m e l l s t r o n g l y o f v a n i l l a or coumarin ( F i g . 1 3 2 a ) . The c o r o l l a tube i s 30-40 mm l o n g w i t h an e n t r a n c e 10-15 mm b r o a d ; d u r i n g d u l l weather the c o r o l l a c l o s e s up ( F i g . 1 3 2 b ) . N e c t a r  is  s e c r e t e d a t the base of t h e o v a r y , around the gynophore. A t about i t s m i d d l e the c o r o l l a tube c o n t r a c t s t o g e t h e r w i t h the e p i p e t a l o u s stipitate  pistil.  l o o s e l y envelops  the  The f l o w e r s are s t r o n g l y p r o t a n d r o u s ;  the  extrorsely-dehiscent as i t m a t u r e s ,  stamens,  somewhat a n d ,  a n t h e r s e n c l o s e the immature s t y l e w h i c h ,  elongates  and bears the two u l t i m a t e l y - r e f l e x e d  s t i g m a t i c l o b e s above the a n t h e r s . Bumble bees c r a w l i n t o f l o w e r s and probe i n t o the b o t t o m , c o n s t r i c t e d h a l f o f the  the  98cv  Fig.  132a.  Gentiana  seeptrum.  A v i e w o f t h e deep  seeptrum.  The  corolla  tube.  Fig.  132b.  Gentiana  overcast, rainy  flowers  weather.  are closed  due  to  99 c o r o l l a for  nectar.  The head o f Trifolium  i s made up o f numerous,  wormskjoldii  s m a l l , p i n k t o r e d - p u r p l e f l o w e r s t h a t , because o f the difficulty  of access to the n e c t a r ,  a r e p o l l i n a t e d almost  e x c l u s i v e l y by bumble b e e s . The c o r o l l a i s connate t o  the  f i l a m e n t tube f o r n e a r l y the e n t i r e l e n g t h o f the stamens, t h a t t h e lower p a r t o f t h e c o r o l l a forms a n a r r o w , s t i f f The consequence  so tube.  i s t h a t i n s e c t v i s i t o r s can put o n l y t h e i r heads  i n s i d e the f l o w e r , and a f a i r l y  long proboscis i s required  r e a c h the bottom o f the c o r o l l a  tube.  The fused p e t a l s nectariferous  tube.  o f Castilleja  parviflora  form a t r u e  The c o r o l l a l o b e s are reduced so t h a t  lower l i p i s represented  to  the  by t h r e e t e e t h w h i l e the upper l i p  forms a s m a l l hood i n c l u d i n g t h e a n t h e r s and most o f the s l i g h t l y e x s e r t e d s t y l e . The a t t r a c t i v e  function i n  Castilleja  has been assumed by showy b r a c t s , which i n C. parviflora albida  are creamy w h i t e t o Lupinus  gullet-type  latifolius  var.  pinkish.  and P e d i c u l a r i s  ( F a e g r i and van der P i j l  b o t h have  bracteosa  1971) bumble bee b l o s s o m s ,  but they d i f f e r s t r i k i n g l y i n t h e i r p o l l i n a t i o n mechanisms. The b r i g h t b l u e p a p i l i o n a c e o u s f l o w e r s o f L. latifolius 13 3) a r e n e c t a r l e s s  (Fig.  but have a marked sweet f r a g r a n c e .  l o w e r , innermost p e t a l s are connate a l o n g t h e i r  The two  adjacent  margins and t o g e t h e r form the k e e l t h a t envelops the 10 The a n t h e r s o f t h e f i v e o u t e r stamens d e h i s c e b e f o r e  stamens.  anthesis  and t h e i r p o l l e n i s s t o r e d i n the h o l l o w cone c o n s t i t u t e d by the t i p o f the k e e l . Under the w e i g h t o f a bumble bee p o l l i n a t o r , t h e f i v e i n n e r stamens' a c t as p i s t o n s , e x t r u d i n g a  100 «,  Fig.  133. L u p i n u s tip of  Fig.  latifolius.  Note the orange p o l l e n at the  of the k e e l , pushed out by the p i s t o n mechanism the flower.  134. P e d i o u l a r i s  bvaoteosa.  The galea i s short-beaked  and helmet-shaped, the s t y l e w e l l e x s e r t e d .  101 s t r i n g o f p o l l e n from the k e e l apex ( F i g . 133) and d e p o s i t i n g it  on the v i s i t o r ' s u n d e r s i d e ; i . e . , s t e r n o t r i b i c a l l y . The  stigma a l s o p r o t r u d e s be e f f e c t e d  at a l a t e r  s t a g e , so t h a t c r o s s i n g can  (Knuth 1906-1909).  The genus Pedioularis  e x h i b i t s a s t r i k i n g s e r i e s of both  p h e n o l o g i c a l and f l o r a l m o r p h o l o g i c a l c o a d a p t a t i o n s bumble b e e s , t h e genus'  major p o l l i n a t o r s ( L i 1951; Sprague  1962 ; M a c i o r 1968a S b , 1969 , 1970a). Pedioularis (Fig.  with  1 3 4 ) , the o n l y one of t h r e e Pedioularis  brc&te.ce<x s p e c i e s i n the  g e n e r a l a r e a t o o c c u r i n B l a c k w a l l Meadow, bears s p i k e s o f yellowish, odorless, nectariferous  f l o w e r s . The upper l i p o f  the fused c o r o l l a forms a b e a k l e s s hood o r g a l e a t h a t the f o u r stamens;  the c a p i t a t e  encloses  stigma i s e x s e r t e d a few m i l l i -  meters beyond the g a l e a t i p . The f l o w e r s are v i s i t e d by l a r g e bumble bees t h a t , a f t e r lip,  g a i n i n g a f o o t h o l d on the lower c o r o l l a  push t h e i r probosces and heads i n t o the c o r o l l a tube i n  search of nectar  s e c r e t e d by a u n i l a t e r a l s w e l l i n g on the lower  s i d e o f the o v a r y . P o l l e n i s thus d e p o s i t e d on the back o f the bumble b e e s ; i . e . , n o t o t r i b i c a l l y . Pedioularis 135), forest  raoemosa  (Fig.  a s p e c i e s more c h a r a c t e r i s t i c a l l y o f s u b a l p i n e f o r e s t c l e a r i n g s , and P. groenlandioa  ( F i g . 1 3 6 ) , much commoner  i n wet seepage areas and f l u s h e s , are the o t h e r two  Pedioularis  s p e c i e s i n the v i c i n i t y o f B l a c k w a l l Meadow. The s t r u c t u r e the f l o w e r s of t h e s e t h r e e s p e c i e s i s markedly d i f f e r e n t , is  and  of as  the p o l l i n a t i n g b e h a v i o r o f t h e i r bumble bee v i s i t o r s  (Sprague 1962; M a c i o r 1968a,1970a; F a e g r i and van der P i j l  1971).  S i n c e the t h r e e s p e c i e s a l s o have s t a g g e r e d peak f l o w e r i n g t i m e s , they are i s o l a t e d e c o l o g i c a l l y , e t h o l o g i c a l l y , and p h e n o l o g i c a l l y .  H  o ro ?  Fig.  135. P e d i o u l a r i s is  raoemosa.  The  galea  long-beaked, t w i s t e d l i k e a  sickle.  Fig.  136. P e d i o u l a r i s  groenlandioa.  The  g a l e a i s extremely long-beaked and extends l i k e an e l e p h a n t ' s trunk.  \0%b  103 Other s p e c i e s i n t h e study communities t h a t are p o l l i n a t e d p r i m a r i l y by bumble bees are Erythronium douglasiana V. o v a t u m ,  3  Hydrophyllum V. o x y c o c c u s ,  fendleri,  grandiflorum, and  V. s o o p a r i u m ,  Vaccinium  Gentiana deliciosum,  V. u l i g i n o s u m  and V.  }  None of t h e s e s p e c i e s except f o r V. oxy coccus  vitis-idaea.  have  p a r t i c u l a r l y s p e c i a l i z e d bumble bee f l o w e r s and are a c c e s s i b l e to other i n s e c t s ; nevertheless,  I have observed bumble bees t o  be t h e i r most numerous and c o n s t a n t p o l l i n a t o r s . Though t h e y a r e not f u s e d , t h e b r i g h t y e l l o w t e p a l s o f Erythronium The  grandiflorum  do form a c o n c e a l e d n e c t a r  chamber.  t e p a l s are r e f l e x e d above, but at t h e i r bases come t o g e t h e r  t o form a s h o r t tube t h a t i s s e a l e d a t the top by a p r o t r u d i n g c o l l a r - l i k e r i n g o f b a s a l s w e l l i n g s on the o u t e r t h r e e p e r i a n t h parts.  Narrow grooves i n the m i d d l e o f the t h r e e o u t e r  tepals  furrow t h r o u g h t h i s c o l l a r and are c o v e r e d by the f i l a m e n t s the grooves serve a s . p a s s a g e s f o r the p o l l i n a t o r ' s p r o b o s c i s . The  n e c t a r i e s are s i t u a t e d at the base of the t e p a l s and  fill  the b a s a l chamber w i t h n e c t a r t h a t i s p r e v e n t e d from t r i c k l i n g out ( t h e f l o w e r s droop a t a n t h e s i s ) 1909) as w e l l as s u r f a c e Gentiana  douglasiana,  by the c o l l a r  tension. with i t s smaller, white, tubular-  campanulate, m o d e r a t e l y n e c t a r i f e r o u s , f a i n t l y flowers,  (Knuth 1906-  fragrant  i s c l e a r l y d i f f e r e n t from i t s bog congener, G.  sceptrum.  The  c o r o l l a tube i s about 12 mm l o n g , w i t h about a 5 mm o r i f i c e .  The  c o r o l l a i s w h i t i s h to greenish-white, with blue nectar  guides d o t t e d on the l o b e s ( F i g . 1 3 7 ) . The s t i g m a t i c l o b e s and a n t h e r s a r e borne a t about the same h e i g h t , but are from one a n o t h e r .  remote  N e c t a r i s s e c r e t e d by g l a n d s a t the base o f  104cu  F i g . 1 3 7 . Gentiana  douglasiana.  The f l o w e r s are m o d e r a t e l y  p r o t a n d r o u s and have w h i t e c o r o l l a l o b e s d o t t e d w i t h blue nectar guides.  F i g . 1 3 8 . Vaccinium  ovatum.  Note t h e e x s e r t e d s t y l e  by a r i n g o f stamens.  encircled  lOHb  105 the s e s s i l e o v a r y . V i s i t i n g bumble bees (the o n l y v i s i t o r s t o G.  t h a t I o b s e r v e d , and they were not  douglasiana  frequent)  work the f l o w e r s w i t h o u t c r a w l i n g down i n t o t h e c o r o l l a as t h e y do i n G e n t i a n a  Hydrophyllum  tube,  sceptrum.  has a w h i t e , campanulate,  fendleri  sympetalous  c o r o l l a 7-10 mm l o n g . Both s t y l e and stamens are e x s e r t e d , each f i l a m e n t i s f l a n k e d by a p a i r o f c i l i a t e , appendages.  linear,  and  corolla  N e c t a r i s s e c r e t e d a t the base o f the o v a r y ,  s t o r e d and c o n c e a l e d i n a c a v i t y o f the p e t a l s , and r i s e & i n the narrow chambers r u n n i n g between the p a i r o f l o n g i t u d i n a l c o r o l l a appendages All  f l a n k i n g t h e m i d r i b o f each p e t a l .  t h e above s p e c i e s o f Vaccinium  except f o r V. oxy-  have s m a l l , w h i t e t o p i n k f l o w e r s w i t h u r n - or  coccus  shaped, sympetalous c o r o l l a s ( F i g . 1 3 8 ) . The s l i g h t l y s t y l e i s c l o s e l y e n c i r c l e d by 10 s h o r t e r  bellexserted  stamens w i t h t e r m i n a l  p o r e s . N e c t a r i s s e c r e t e d at the base o f t h e s t y l e and an i n s e c t must push i t s tongue between the c i r c l e o f stamens t o r e a c h i t , and i n so d o i n g d i s l o d g e s p o l l e n from the a n t h e r s o f t h e g e n e r a l l y pendent The  flowers.  f l o w e r o f Vaccinium  four r e f l e x e d petals  oxycoccus  (Ericaceae), with  and r i n g o f e i g h t stamens e n c i r c l i n g  its the  e x s e r t e d s t y l e ( F i g . 139) , bears a r e m a r k a b l e resemblance t o a Dodecatheon  ( P r i m u l a c e a e ) f l o w e r ( F i g . 1 4 0 ) . M a c i o r (1964, 1970b)  has made d e t a i l e d o b s e r v a t i o n s on t h e p o l l i n a t i o n e c o l o g y o f Dodecatheon.  P o l l i n a t i o n i s a c c o m p l i s h e d by bumble bees t h a t  hang i n v e r t e d from the cone o f connate a n t h e r s and w i n g - v i b r a t e p o l l e n onto t h e i r b o d i e s . I have observed p o l l i n a t i o n o f V.  ho cn  1  P  Fig.  139. Vaooinium  oxyoooous  (Ericaceae).  F i g . 140. Dodecatheon  In both f l o w e r s , note the r e l e x e d , f l a r e d and t h e s t y l e exserted from the enveloping c y l i n d e r of stamens.  petals,  jeffreyi  (Primulaceae).  107 by bumble bees i n the sphagnum b o g s , and t h e mechanism  oxycoccus  agrees c l o s e l y  w i t h t h a t o f Dodecatheon  as d e s c r i b e d by M a c i o r .  The f l o w e r s d i f f e r i n t h a t t h o s e o f Dodecatheon but f r a g r a n t nectaries  are  nectarless  w h i l e t h o s e of V. oxycoccus  have a r i n g o f s m a l l  a t t h e base o f t h e s t y l e j u s t  i n s i d e the stamens but  have no p e r c e p t i b l e o d o r . Convergent e v o l u t i o n must have been involved here,  and i n the o c c u r r e n c e o f s t r i k i n g l y s i m i l a r  f l o w e r form i n Solanum  and Lycopersicon  (Solanaceae).  Moth p o l l i n a t i o n ( p h a l a e n o p h i l y )  Moth p o l l i n a t i o n i s w e l l - d e v e l o p e d i n o n l y o f the in  the  present study, S i l e n e  parryi  (Fig.  14la  £ b).  species  Silene  f i t s almost p e r f e c t l y the moth p o l l i n a t i o n syndrome  parryi  o u t l i n e d i n F a e g r i and van der P i j l  ( 1 9 7 1 ) . The w h i t e f l o w e r s ,  c l o s e d and a p p e a r i n g w i l t e d i n the d a y t i m e , open a t n i g h t and during anthesis  emit a h e a v y - s w e e t ,  p e r v a s i v e perfume.  The  h o r i z o n t a l blossoms are v i s i t e d by n o c t u r n a l hawk moths ( L e p i d o p t e r a , H e t e r o n e u r a , S p h i n g i d a e ) t h a t hover i n f r o n t o f the flowers without a l i g h t i n g (these observations  corroborated  by A . R . K r u c k e b e r g , p e r s o n a l c o m m u n i c a t i o n ) . The l o b e d and f r i n g e d e p i p e t a l o u s appendages o f S. parryi  petals  reflect  the  s e n s i t i v i t y o f moths t o d i s s e c t e d o u t l i n e s ( F a e g r i and van der Pijl  1971). The f l o w e r s are a b u n d a n t l y n e c t a r i f e r o u s  nectar  but  the  i s s e c r e t e d a t the base o f t h e ovary and i s c o n c e a l e d  by a f l o r a l tube about 11 mm l o n g . T h i s t u b e , formed by a s y n s e p a l o u s , b l a d d e r - l i k e c a l y x t h a t h o l d s the l o n g claws o f free petals  the  f i r m l y t o g e t h e r , i s e a s i l y a c c e s s i b l e to the long  108cv  Fig.  141a. S i l e n e  parryi.  The flowers as they appear i n  mid-day.  Fig.  141b. S i l e n e  parryi.  Night. Note the d i s s e c t e d o u t l i n e  and the h o r i z o n t a l b e a r i n g o f the f l o w e r .  l<Ab  109 sphingicL proboscis.  B u t t e r f l y p o l l i n a t i o n (psychophily)  B u t t e r f l i e s and s k i p p e r s an i m p o r t a n t  ( L e p i d o p t e r a , Rhopalocera)  form  c l a s s o f p o l l i n a t o r s i n B l a c k w a l l Meadow. They are  p a r t i c u l a r l y common v i s i t o r s to f l o w e r s o f Compositae such as Arnica  latifolia  triangularis,  Erigeron  Senecio  peregrinus,  and  integerrimus especially  and  sitchensis.  Valeriana  B u t t e r f l y blossoms  g e n e r a l l y e r e c t , r a d i a l , and f a i r l y f l a t , butterflies of  a l i g h t on t h e i r  and S.  Agoseris  They a l s o s t r o n g l y f a v o r the blossoms o f  aurantiaca. diffusa  and A. m o l l i s ,  Phlox are  as most p o l l i n a t i n g  f l o w e r s r a t h e r t h a n hover i n  front  them. B u t t e r f l y f l o w e r s have ample n e c t a r i n tubes o r spurs  and they a l s o tend t o be v i v i d l y c o l o r e d . B e h a v i o r a l s t u d i e s on  butterfly  butterflies  c o l o r p e r c e p t i o n and p r e f e r e n c e have found t h a t show peak r e s p o n s e t o the orange r e d and b l u e  r e g i o n s o f the spectrum ( U s e 1928 ; S w i h a r t and S w i h a r t 1970 ; L e v i n 1972a). A g o s e r i s  aurantiaca  and P h l o x  p r o b a b l y the b e s t developed b u t t e r f l y Agoseris  diffusa  f l o w e r s i n the  have  meadow.  (Tig. 14-2) has b r i l l i a n t b u r n t - o r a n g e  aurantiaca  f l o w e r s ; Phlox'diffusa  ( F i g . 143) d i s p l a y s i n t e n s e mauve t o  p a l e b l u e blooms.  Hummingbird p o l l i n a t i o n  The o n l y p r e d o m i n a n t l y h u m m i n g b i r d - p o l l i n a t e d f l o w e r i n this  study i s Castilleja  miniata.  This species  i s i n c l u d e d as  110 CO  Fig.  142. Agosevis  auvantiaoa.  The b u r n t - o r a n g e ,  f l o w e r s are aggregated i n a c a p i t a t e  Fig.  143. Phlox  capitulum.  The s a l v e r f o r m c o r o l l a s have w i d e -  diffusa.  spreading,  ligulate  h o r i z o n t a l l a n d i n g ..platforms  the a n t h e r s and  stigma.  and  include  nob  Ill a c o n f i r m e d hummingbird f l o w e r i n Grant and G r a n t ' s (19 68) monograph on hummingbird p o l l i n a t i o n . I n B l a c k w a l l Meadow, Castilleja  miniata  (Selasphorus  rufus).  i s p o l l i n a t e d by the Rufous hummingbird The b r i l l i a n t s c a r l e t t o deep r e d ,  i n f l o r e s c e n c e s o f C. miniata  odorless  ( F i g . 144) c o n s i s t o f b r i g h t l y  colored bracts that.envelop  l o n g , g r e e n i s h 20-40 mm t u b u l a r  c o r o l l a s . The l e n g t h o f the c o r o l l a tube corresponds t o  the  17-21 mm b i l l p l u s e x t e n s i b l e tongue l e n g t h o f the Rufous hummingbird (Grant and G r a n t - 1 9 6 8 ) . I n c o n t r a s t ,  C.  v a r . albida,  subalpine  the o t h e r Castilleja  s p e c i e s i n the  parviflora  meadow, has a 12-18 mm l o n g c o r o l l a tube and i s p o l l i n a t e d by bumble bees. In p o l l i n a t i n g C. miniata,  the hummingbirds probe  the  f l o w e r s f o r t h e abundant n e c t a r t h a t i s s e c r e t e d a t the base o f the c o r o l l a t u b e .  I n so d o i n g , they r e c e i v e p o l l e n on the  of the head o r upper b i l l base from the a n t h e r s t h a t  top  are  e n c l o s e d i n the b e a k l i k e upper l i p ( g a l e a ) . A t the same time p o l l e n may be t r a n s f e r r e d  t o the s l i g h t l y e x s e r t e d s t y l e .  Studies  o f hummingbird d i s p e r s a l o f p o l l e n l a b e l l e d w i t h r a d i o a c t i v e i o d i n e i n d i c a t e t h a t hummingbirds are' e x t r e m e l y vectors.,  at l e a s t w i t h i n l o c a l populations  efficient  ( S c h l i s i n g and  Turpin 1971). The p r e v a l e n c e o f r e d as the predominant c o l o r o f n o r t h western American hummingbird f l o w e r s has provoked an hypothesis.  Grant (1966)..suggested  c o l o r i n s p e c i e s o f many d i f f e r e n t  t h a t t h i s convergence i n f a m i l i e s and genera i s not  n e c e s s a r i l y due t o hummingbird p r e f e r e n c e is  interesting  f o r r e d , but  instead  r e l a t e d t o the f a c t t h a t , w h i l e hummingbirds p e r c e i v e r e d ,  H H  Fig.  144. Castilleja tubular,  miniata  has l o n g -  greenish c o r o l l a s  amidst f l a m e - r e d b r a c t s .  F i g . 145. Anemone  oooidentalis,  in fruit.  achenes are t i p p e d w i t h l o n g , silky-plumose styles.  The sinuous,  I l i b  113 bees do n o t . T h i s b e i n g s o , a common f l o r a l s e l e c t i v e l y advantageous  c o l o r would be  t o b o t h t h e m i g r a t o r y hummingbirds and  t h e i r f l o w e r s i n t h a t i t would f a c i l i t a t e q u i c k p o l l i n a t o r r e c o g n i t i o n o f f l o w e r s and would reduce c o m p e t i t i o n from beepollinated species.  Such f l o r a l m i m i c r y has been mentioned by  M a c i o r (1971) and i s c o n s i s t e n t w i t h t h e o r y  (Straw 1972).  F u r t h e r m o r e , as Raven ( 1 9 7 2 ) . p o i n t s o u t , the h i g h requirements  energetic  o f hummingbirds are b e s t s a t i s f i e d by a f l o w e r  w i t h abundant  nectar,  no odor (hummingbirds respond o n l y  secondarily to odor, u n l i k e insects  (Grant and Grant 1 9 6 8 ) ) ,  and a c o l o r s i g n a l d i s t i n g u i s h a b l e by b i r d s but not  conspicuous  t o i n s e c t s t h a t c o u l d d e p l e t e the s u p p l y o f much-needed  nectar;  t h a t i s t o s a y , such a f l o w e r would be the p r o t o t y p e o f a hummingbird f l o w e r .  Implications  As  has been mentioned b e f o r e ,  the m a j o r i t y o f the- s a l t  marsh p l a n t s are anemophilous, sphagnum bog p l a n t s are more e q u a l l y anemophilous and e n t o m o p h i l o u s , and s u b a l p i n e meadow p l a n t s are p r i m a r i l y e n t o m o p h i l o u s . There are differences  corresponding  i n the p r o p o r t i o n s o f showy-flowered s p e c i e s  the communities. N e v e r t h e l e s s , the b u l k o f the s p e c i e s vegetation i n a l l four s i t e s  in  and  i s predominantly o u t c r o s s i n g  (see  p r e v i o u s d i s c u s s i o n and S e c t . I I I - J and Appendix 3 ) , as most of  the  self-compatible  groenlandicum, Delphinium  species  Vaccinium  spp.,  n u t t a l l i a n u m , Phleum  (eg. , K a l m i a Erythronium alpinum,  polif'olia,  Ledum  grandiflorum,  Carex  spp.,  Juncus  spp.  114 have f l o r a l b i o l o g i e s promoting o u t c r o s s i n g . There i s no major shift  t o s e l f - p o l l i n a t i o n o r a p o m i x i s i n any o f the communities Mosquin (19 66) t h e o r i z e d t h a t . s p e c i e s  of h a r s h p h y s i c a l  environments w i l l tend t o have r e p r o d u c t i v e s p e c i a l i z a t i o n s t h a t reduce -. the amount of g e n e t i c v a r i a b i l i t y ,  suggesting that  g e n e t i c u n i f o r m i t y and p r e s e r v a t i o n o f s h o r t - t e r m f i t n e s s may a c t u a l l y be a d a p t i v e i n such e n v i r o n m e n t s . One o b v i o u s r e p r o d u c t i v e s p e c i a l i z a t i o n t e n d i n g toward g e n e t i c u n i f o r m i t y would i n v o l v e r e d u c i n g the amount o f o u t b r e e d i n g i n a s p e c i e s p o p u l a t i o n by a s h i f t t o s e l f - f e r t i l i z a t i o n  or apomixis.  Kevan (1970, 1972) and S a v i l e (1972) i n d i c a t e d no pronounced t r e n d toward i n b r e e d i n g i n p l a n t s p e c i e s o f the h a r s h A r c t i c t u n d r a . My o b s e r v a t i o n s  l i k e w i s e show no such t r e n d i n any o f  the t h r e e v e g e t a t i o n types I have s t u d i e d . A l l t h r e e e x i s t i n p h y s i c a l environments t h a t must be c o n s i d e r e d " h a r s h " i n at l e a s t some r e s p e c t s .  But i f M o s q u i n ' s h y p o t h e s i s i s t o be  t e s t e d by my r e s u l t s a more i n c l u s i v e e v a l u a t i o n of  the.species  r e c o m b i n a t i o n s y s t e m s , o f which p o l l i n a t i o n and o u t c r o s s i n g mechanisms are but one a s p e c t , w i l l be r e q u i r e d (see III-J).  Sect.  115 F. D i s p e r s a l e c o l o g y .  A l o n g w i t h p o l l e n d i s p e r s a l , the o t h e r v e h i c l e o f gene f l o w ( a p a r t from v e g e t a t i v e d i s p e r s a l ) plants  a v a i l a b l e to flowering  i s r e p r o d u c t i o n by seed. As S t e b b i n s  (1971a) has  pointed  o u t , t o be s u c c e s s f u l such r e p r o d u c t i o n r e q u i r e s an i n t e g r a t i o n of d i f f e r e n t  functions  structurescand  and a c o o r d i n a t i o n between m o r p h o l o g i c a l  p h y s i o l o g i c a l processes  such as f r u i t r i p e n i n g ,  seed dormancy, and s e e d l i n g g r o w t h . S a l i s b u r y ( 1 9 4 2 ) , (1950, 1971a), P i j l  Stebbins  (1969) and Baker (1972) have emphasized  the e c o l o g i c a l consequences  o f t h e d i s p e r s a l system and t h e  c o r r e l a t i o n s t h a t may be made between d i s p e r s a l type and habitat.  The above a u t h o r s and C a r l q u i s t ( 1 9 6 6 ) , Janzen  (1969,  1971a), and H a r p e r , L o v e l l , and Moore (1970) have o u t l i n e d some o f the a d a p t i v e compromises between seed s i z e , seed number, and d i s p e r s a l agent t h a t ensure s u c c e s s f u l in particular  reproduction  habitats.  The f o l l o w i n g d i s c u s s i o n c e n t e r s on the d i a s p o r e morphology and mode o f d i s p e r s a l o f t h e angiosperm s p e c i e s o f the four study s i t e s ,  and touches on some o f the e c o l o g i c a l  i m p l i c a t i o n s a t the community l e v e l . mode(s)  of diaspore transport  I n many c a s e s ,  the  actual  does (do) not f o l l o w from  d i a s p o r e morphology. In t h e s e cases I have t r i e d t o make reasonable  conjectures  t h a t r e l y h e a v i l y on p u b l i s h e d  i n c l u d i n g Kerner (1896), R i d l e y (1930), P i j l Stebbins  accounts,  ( 1 9 6 9 ) , and  (1971a).  The p r o p a g u l e type and mode o f d i s p e r s a l f o r each are g i v e n i n Appendix 3. Trends i n d i s p e r s a l systems  species  within  116 each community are summarized i n T a b l e s 14 and 15. T a b l e 14 i s based on a m o r p h o l o g i c a l c l a s s i f i c a t i o n o f d i a s p o r e  types  s l i g h t l y m o d i f i e d from F r e n k e l (1970) and o u t l i n e d i n T a b l e 13  TABLE 13. O u t l i n e o f d i a s p o r e  Diaspore type  Auxochore Cyclochore Pterochore Pogonochore Desmochore Sarcochore Sporochore Microsclerochore Megasclerochore Barochore Ballochore  types.  Description  No d i s a r t i c u l a t i o n from parent p l a n t before d i a s p o r e i s d e p o s i t e d a t s i t e of f u r t h e r development. D i a s p o r e v e r y voluminous i n r e l a t i o n t o actual reproductive part. D i a s p o r e w i t h s c a r i o u s , w i n g l i k e , or s a c c a t e appendages. D i a s p o r e w i t h l o n g , h a i r l i k e , or plumose appendages. Diaspore w i t h s h o r t , s t i f f , s p i n y , glandular or hooked appendages a d h e r i n g t o rough surfaces. D i a s p o r e w i t h o u t appendage but w i t h j u i c y or f l e s h y o u t e r l a y e r s . D i a s p o r e l i g h t enough t o be c a r r i e d by b r e e z e ( 0 . 0 0 1 - 0 . 0 4 9 mg). D i a s p o r e w i t h o u t appendage, t o o heavy t o be c a r r i e d by breeze ( 0 . 0 5 0 - 0 . 4 9 9 mg). D i a s p o r e w i t h o u t appendage, t o o heavy t o be c a r r i e d by breeze ( 0 . 5 0 0 - 9 9 9 . 0 mg). D i a s p o r e w i t h o u t appendage and v e r y heavy (1000.0+ mg). P a r e n t p l a n t has mechanism f o r d i a s p o r e expulsion.  T a b l e 14 g i v e s the percentages  o f each propagule t y p e i n  the f l o r a o f each s i t e . Note t h a t the c a t e g o r i e s are e x c l u s i v e ; e g . , t h e i n d e h i s c e n t c a p s u l e o f Plantago (Fig.  147) i s a m e g a s c l e r o c h o r e , w h i l e the s e e d , w i t h  not maorooarpa its  117 m u c i l a g i n o u s seed c o a t , would be a desmochore when l i b e r a t e d and  w e t t e d . Presumably b o t h h y d r o c h o r y and a d h e s i v e e p i z o o -  chory are e f f e c t i v e means o f d i s p e r s a l i n t h i s  TABLE 14. P e r c e n t a g e s  S a l t Marsh (%)  Diaspore type  Auxochore Cyclochore Pterochore Pogonochore Desmochore Sarcochore Sporochore Microsclerochore Megasclerochore Ballochore  of diaspore  Wade's Bog (%)  11.1 5.6 38.9 5.6 33.3 50.0  "'"There are no b a r o c h o r e s  The  2.9  16.0 4.0 8.0 24. 0 16.0 20.0 28.0  11.4 8.6 14.7 2 5.7 11.4 22.9 35.0  Blackwall Meadow (%)  17.8 26.7 22.2 4.5 2.2 28.9 26.7 4.5  i n any o f the c o m m u n i t i e s .  The f r u i t s o f t h i s  w i n t e r e d uneaten and s t i l l  is  c r a n b e r r y can f r e q u e n t l y moss, h a v i n g o v e r -  a t t a c h e d t o t h e p a r e n t p l a n t . The  seeds c o u l d c o n c e i v a b l y germinate in situ decomposes the f o l l o w i n g summer  Glaux  Ogg's Bog (%)  4.0  be found l y i n g i n t a c t on a bed o f Sphagnum  The  1  o n l y s p e c i e s t h a t may have an auxochorous d i a s p o r e oxyoooous.  Vaooinium  types.  species.  as the b e r r y  but t h i s i s  questionable.  s a l t marsh has the o n l y two c y c l o c h o r o u s s p e c i e s :  maritima  and S a l i o o r n i a  virginioa.  In G l a u x ,  the  seeds  adhere t o t h e spongy p l a c e n t a . The spongy p e r i a n t h o f S a l i o o r n i a is  accrescent  t o t h e i n d e h i s c e n t u t r i c l e . Both of t h e s e compound  118 d i s p e r s a l u n i t s a r e bouyant and p r o b a b l y are d i s p e r s e d r e l a t i v e l y s h o r t d i s t a n c e s by the t i d e s .  for  In S a l i o o r n i a ,  entire  segments o f the f l e s h y stems (see F i g . 116) t h a t break o f f and can  f l o a t i n seawater  f o r up t o t h r e e months (Dalby 1963).  c o u l d a l s o f u n c t i o n as c y c l o c h o r o u s d i a s p o r e s . There are a number o f p t e r o c h o r o u s  s p e c i e s i n the  sphagnum  bogs and the s u b a l p i n e meadow, but none i n the s a l t marsh. Drosera  rotundifolia,  and C. parviflora  Tofieldia  miniata,  have l o o s e l y t e s t a t e s e e d s ; Myrioa  Sanguisorba  officinalis,  Pedioularis  bracteosa,  fruits;  glutinosa, Castilleja  Delphinium  Arenaria capillaris,  and  Veratrum  viride  gale,  Veronica  cusickii  have winged seeds  n u t t a l l i a n u m and P e n s t e m o n p r o c e r u s  or  have  q u i t e s i m i l a r , s h i n y - b l a c k , w i n g - a n g l e d seeds w i t h somewhat loose, puckered, r e t i c u l a t e  testas.  Pogonochores are r e p r e s e n t e d fruits  p r i m a r i l y by the  o f t h e Compositae. The achene o f Valeriana  f i t t e d w i t h the p e r s i s t e n t ,  pappose sitchensis  ,  pappus-like calyx, i s similar  to  the Compositae pogonochore. The c l u s t e r o f pogonochores o f Anemone  occidentalis  ( F i g . 145) puts on a superb d i s p l a y o f  numerous v i l l o u s achenes t i p p e d w i t h l o n g , s i l k y - p l u m o s e s t y l e s the ":mop t o p s " o r "tow-headed b a b i e s " o f s u b a l p i n e meadows Other pogonochores are the p l u m o s e - p e r i a n t h e d n u t l e t s o f p o l y s t a c h i o n , the  Eriophorum  the t a i l e d seeds of Junous Desohampsia  comose seeds o f E p i l o b i u m  alpinum,  , and the awned f r u i t s o f  drummondii  oespitosa.  I have c l a s s e d the v a r i o u s l y - a p p e n d a g e d p r o p a g u l e s o f the grasses D e s o h a m p s i a antherum,  oespitosa,  Calamagrostis  Festuoa  nutkaensis,  rubra,  Phleum  Eordeum  alpinum,  brachyTrisetum  119 spicatum  g l a u o u s , and P o a  Elymus  3  c u s i c k i i as  desmochores  because they can e a s i l y adhere t o r o u g h - s u r f a c e d a n i m a l s and be e p i z o o c h o r o u s l y d i s p e r s e d ( R i d l e y 1930; P i j l . 1 9 6 9 ; 1971a). The legume p l u s s p i n y , adherent  calyx of  and the c a p s u l e p l u s a t t a c h e d ,  wormskholdii  c a l y x o f Eydrophyllum  g l a n d u l a r , i n d e h i s c e n t c a p s u l e o f Linnaea seeds o f Spergularia  and M i c r o s t e r i s  stiff-ciliate  gracilis  , the  borealis  c a n a d e n s i s , and the  m u c i l a g i n o u s - w h e n - w e t t e d seeds o f Plantago maritima,  Tvifolium  are a l s o desmochores. The  fendleri  glandular-pubescent  are  macrocarpa  3  examples o f  desmochores. The beaked p e r i g y n i a o f Carex  and Thalictrum  persistent,  have a l s o  canescens  shallon,  by  Ranunculus  , which are b e s e t w i t h  occidentale  s l i g h t l y curved s t y l e s .  S a r c o c h o r e s are r e p r e s e n t e d Vaccinium  P.  sticky  been c l a s s e d desmochores, as have the achenes o f eschscholtzii  Stebbins  species, of E m p e t r u m Maianthemum  t h e drupe o f Cornus  by the b e r r i e s o f a l l (Fig.  nigrum  dilatatum,  146),  and L y s i a h i t u m  Gaultheria and  americanum,  u n a l a s a h k e n s i s . The s a l t marsh has no  sarcochorous s p e c i e s and the s u b a l p i n e meadow has o n l y two (.Vaccinium  deliciosum  b o t h bogs i s 2 5%  and  V. s c o p a r i u m ) , w h i l e the  flora  of  sarcochorous.  Only a few s p e c i e s have seeds l i g h t enough t o be c l a s s e d s p o r o c h o r e s : t h e y are formisj  Drosera  •groenlandicum.  Juncus  rotundifolia  balticus 3  Kalmia  3  J. d r u m m o n d i i  polifolia  3  and  3  J.  supini  Ledum  M i c r o - " and megasclerochores are common i n a l l  the communities. The o n l y b a l l o c h o r e s a r e found i n B l a c k w a l l Meadow. The seeds o f Lupinus  latifolius  are  ballistically  d i s p e r s e d by an e x p l o s i o n o f the r i p e legume and  subsequent  120cv  Fig.  146.  Empetrum  nigrum.  sarcochorous  Fig.  147. Plantago of  The b l a c k b e r r y i s a  propagule.  maorooarpa.  The f r u i t i n g  somewhat i n f l a t e d , i n d e h i s c e n t  spike consists capsules.  121 Claytonia  s p i r a l t o r s i o n o f the pod v a l v e s ( R i d l e y 1930). I n lanoeolata,  the mature,  erect  capsule s p l i t s i n t o three valves  t h a t f i r s t spread o u t , c r a d l i n g the 3 ( u s u a l l y ) - 6 o v o i d , p o l i s h e d , b l a c k seeds. As the v a l v e s d r y , they p i n c h inwards u n t i l pressure i s s u f f i c i e n t to eject  one o r more of the  their  contiguous  seeds ( R i d l e y 1930). Table 15 c o n t a i n s a summary o f the p e r c e n t a g e s o f s i x major modes o f d i s p e r s a l i n both the f l o r a and v e g e t a t i o n o f all  f o u r communities. Due t o t h e d i f f i c u l t y  of d i r e c t  observation,  most o f the d i s p e r s a l types have been i n f e r r e d , but i t s h o u l d be r e p e a t e d  t h a t one cannot n e c e s s a r i l y deduce  dispersal  method from d i a s p o r e morphology; Most o f t h e s p e c i e s employ more than one mode o f d i s p e r s a l , so the t o t a l s  of  the  percentages o f v a r i o u s d i s p e r s a l methods f o r each community exceed 100%. I n cases where i t was d o u b t f u l which o f two a l t e r n a t i v e methods are u t i l i z e d by a p a r t i c u l a r s p e c i e s , alternatives  were  both  counted.  TABLE 15. Percentages  o f d i s p e r s a l methods;  Dispersal method  S a l t Marsh Wade's Bog Ogg's Bog B l a c k w a l l (%) (%) (%) Meadow (%)  Autochory Hydrochory 50/U0 Anemochory 61/70 Endozoochory E p i z o o c h o r y (mud) 100/100 E p i z o o c h o r y (adhesion) 39/53  44/48 52/63 24/10 48/55 8/6  flora/vegetation.  43/51 51/59 26/10 46/55 17/8  4/14 7/1 91/92 4/3 23/11  122 A few g e n e r a l c o n c l u s i o n s can be drawn from T a b l e 15. A b i o t i c d i s p e r s a l methods are v e r y i m p o r t a n t i n a l l f o u r communities. P r e d i c t a b l y , s p e c i e s o f the w e t l a n d communities (bog  and s a l t marsh) r e l y much more on water d i s p e r s a l t h a n the  s u b a l p i n e meadow s p e c i e s , which are p r e d o m i n a n t l y w i n d - d i s p e r s e d . Many o f the s a l t marsh and bog s p e c i e s are hydrochorous merely because t h e y grow i n wet areas  t h e i r p r o p a g u l e s a r e not  p a r t i c u l a r l y adapted f o r f l o t a t i o n . However, the somewhat inflated, 147),  i n d e h i s c e n t c a p s u l e s o f Plantago  t h e spongy d i a s p o r e s o f Salicornia  walled p e r i g y n i a of C a r e x  lyngbyei  the c o r k y m e r i c a r p s o f Lilaeopsis winged f r u i t s  all  of M y r i c a  gale  (Fig.  macrocarpa  the t h i c k -  virginica, ( F i g . 148)  oooidentalis and S a n g u i s o r b a  and C. o b n u p t a ,  , and the  corky,  officinalis  are  w e l l adapted f o r bouyancy and water d i s p e r s a l . S p l a s h - c u p d i s p e r s a l ( B r o d i e 1951; S a v i l e 1953) i s a  unique t y p e of s h o r t - d i s t a n c e h y d r o c h o r y employed by asplenifolia by  Gentiana  ( F i g . 1 4 9 ) , p r o b a b l y by C. trifolia,  Coptis  and perhaps  The smooth seeds are e j e c t e d from the  douglasiana.  f l a r e d l i p s of the open f r u i t s by f a l l i n g water drops t h a t score d i r e c t h i t s . The  predominance o f wind d i s p e r s a l i n B l a c k w a l l Meadow i s  r e f l e c t e d i n the l a r g e number o f p t e r o c h o r o u s and pogonochorous s p e c i e s . P t e r o c h o r e s and pogonochores are o b v i o u s l y morphol o g i c a l l y adapted f o r anemochory; most o f the m i c r o - and megas c l e r o c h o r e s i n the meadow are a l s o anemochorous, but i n a l e s s obvious way. The f r u i t i n g  s t a l k s o f many s u b a l p i n e meadow  s p e c i e s remain e r e c t above t h e f i r s t e n c r u s t e d snows o f e a r l y winter. The•frequent,  s t r o n g mountain winds must o f t e n  jostle  123a,  Fig.  148. Carex  thick-walled  Fig.  149. Coptis  , fruiting  lyngbyei  spike.  Note the  plump,  perigynia.  asplenif'olia  for splash-cup  has  fruiting  dispersal.  follicles  adapted  124 seeds l o o s e from t h e i r f r u i t s and blow them f o r r e l a t i v e l y l o n g d i s t a n c e s a c r o s s the hardened s u r f a c e b e f o r e the heavy snows set i n . T h i s type o f d i s p e r s a l c o u l d augment the r e l a t i v e l y l o c a l d i s s e m i n a t i o n o f seeds by the c e n s e r mechanism (as i n Pedicularis  and Erythronium  bracteosa,  Castilleja  grandiflorum),  miniata  and  C. p a r v i f l o r a ,  and c o u l d c o n c e i v a b l y account  for  movement o f g r e a t d i s t a n c e s from r i d g e t o p t o r i d g e t o p even  for  such h e a v y , unappendaged  Lupinus  latifolius,  seeds as t h o s e o f E.  or H y d r o p h y l l u m  fendleri.  Savile  grandiflorum, (1972)  c o n s i d e r s a s i m i l a r mode o f d i s p e r s a l t o be of prime importance to A r c t i c  species.  B i o t i c d i s p e r s a l i n g e n e r a l i s most i m p o r t a n t i n the  salt  marsh, o f i n t e r m e d i a t e importance i n the sphagnum b o g s , and l e a s t i m p o r t a n t i n the s u b a l p i n e meadow. B i o t i c d i s p e r s a l i n the s a l t marsh i s p r e d o m i n a n t l y e p i z o o c h o r o u s , and the is  p r i m a r i l y i n mud t h a t adheres t o the f e e t  w a t e r f o w l and the f e e t  transport  and plumage o f  and h a i r o f g r a z i n g a n i m a l s ( R i d l e y 1930).  T r a n s p o r t by a d h e s i o n o f desmochores t o a n i m a l s a l s o p l a y s an i m p o r t a n t r o l e i n marsh seed d i s p e r s a l . D i s p e r s a l v i a a n i m a l i n g e s t i o n of f l e s h y f r u i t s  (endozoochory) i s common i n the  sphagnum b o g s , but the s a r c o c h o r o u s s p e c i e s are minor elements of  the bog v e g e t a t i o n (Table 1 5 ) . B i o t i c d i s p e r s a l i n the  s u b a l p i n e meadow i s p r i m a r i l y by a d h e s i v e e p i z o o c h o r y , but s i m i l a r l y the desmochores b e l o n g t o s u b o r d i n a t e In  species.  summary, b i o t i c d i s p e r s a l i s much more p r e v a l e n t i n the  s a l t marsh and bogs than i n the s u b a l p i n e meadow, where most o f the s p e c i e s are w i n d - d i s p e r s e d . What i s the s i g n i f i c a n c e o f t h i s g e n e r a l d i f f e r e n c e i n community d i s p e r s a l p a t t e r n s ?  125 S t e b b i n s (1971a) m a i n t a i n s t h a t a n i m a l d i s p e r s a l i s more efficient  than wind d i s p e r s a l a c r o s s l o n g d i s t a n c e s  because  a n i m a l s , e s p e c i a l l y m i g r a t o r y a n i m a l s , are more p r e d i c t a b l e i n t h e i r movements and more s e l e c t i v e i n h a b i t a t - t o - h a b i t a t  trans-  p o r t t h a n i s w i n d . The l i k e l i h o o d t h a t seeds w i l l be d i s p e r s e d when r i p e and t r a n s p o r t e d t o f a v o r a b l e h a b i t a t s o c c u p i e d by t h e p a r e n t p l a n t s i s g r e a t e r  s i m i l a r to  those  i n animal d i s p e r s a l .  None o f t h e t h r e e v e g e t a t i o n types are e x t e n s i v e o r c o n t i n u o u s i n n o r t h w e s t e r n N o r t h A m e r i c a . S a l t marshes and c o a s t a l sphagnum bogs occur i n i s o l a t e d patches a l o n g the n o r t h P a c i f i c coast.  I n view o f t h e extreme i m p r o b a b i l i t y and l i k e l y  i n e f f i c a c y o f l o n g d i s t a n c e p o l l i n a t i o n .(cf. E h r l i c h a n d Raven 5  19 69; E n d l e r 1 9 7 3 ) , gene flow between p o p u l a t i o n s o f marsh and bog s p e c i e s must be p r i m a r i l y v i a l o n g d i s t a n c e seed d i s p e r s a l by a n i m a l s . S u b a l p i n e meadows, though f a r from b e i n g a c o n t i n u o u s or dominant element o f t h e t o t a l v e g e t a t i o n , are much more e x t e n s i v e i n the c o r d i l l e r a o f P a c i f i c N o r t h A m e r i c a t h a n are s a l t marshes and bogs a l o n g the c o a s t . Mountain meadows c o u l d a c t as s t e p p i n g stones f o r a sequence o f r e l a t i v e l y s h o r t ,  wind-  d i s p e r s e d h o p s , and i n t h i s s i t u a t i o n i n t e r p o p u l a t i o n gene  flow  i s p r o b a b l y not as dependent on l o n g d i s t a n c e seed d i s p e r s a l . F u r t h e r m o r e , gene flow v i a p o l l i n a t i n g i n s e c t s i s p r o b a b l y more efficient  i n the meadows, not o n l y because i n s e c t p o l l i n a t i o n  i s much more common but a l s o because e f f e c t i v e l o n g  distance  p o l l i n a t i o n i s mediated more f r e q u e n t l y by i n s e c t s t h a n wind ( E h r l i c h and Raven 1969; Janzen 1971b). Thus i t appears t h a t  the  two methods o f gene f l o w i n p l a n t s , p o l l i n a t i o n and d i s p e r s a l , a c t i n c o n c e r t and compensation i n m a i n t a i n i n g what one must  126  assume i s an optimum or near-optimum rate of gene exchange within the species of the community  types.  127 G. V a r i a b i l i t y and n i c h e w i d t h .  C o n s i d e r an n - d i m e n s i o n a l hyperspace along coordinates  abstractly  constructed  corresponding to a l l variables relevant  the l i f e o f a s p e c i e s .  H u t c h i n s o n (1965) d e f i n e s  the  n i c h e as t h a t hypervolume w i t h i n the h y p e r s p a c e , o f which corresponds  t o a s e t o f v a l u e s o f the  to  species'  "every p o i n t variables  p e r m i t t i n g the organism t o e x i s t . " A l t h o u g h a n i c h e d e s c r i p t i o n i s based t o a g r e a t e x t e n t on t h e p h y s i c a l parameters o f a species'  existence,  i t remains i n c o m p l e t e w i t h o u t i n c l u s i o n o f  i t s b i o t i c components.  As Major (19 58) has w r i t t e n , " . . . a s a  m a t t e r o f f a c t , no p h y s i o l o g i c a l d a t a known t o the w r i t e r have been a b l e t o e x p l a i n why a p a r t i c u l a r p l a n t grows n a t u r a l l y where i t does w i t h o u t a p p e a l i n g to c o m p e t i t i o n as a g e n e r a l term r e f e r r i n g t o the i n t e r r e l a t i o n s  of plants."  Such  c o n s i d e r a t i o n s have prompted H u t c h i n s o n (1957, 1965) d i s t i n g u i s h the "fundamental species'  to  n i c h e " ( t h a t c o n s t i t u t e d by a  hypervolume i f no c o m p e t i t o r s  " r e a l i z e d n i c h e " , which r e s u l t s  are p r e s e n t ) from the  from i n t e r s p e c i f i c c o m p e t i t i o n .  C o m p e t i t i o n has been d e f i n e d as the " a c t i v e demand o f same s p e c i e s p o p u l a t i o n ( i n t r a s p e c i f i c ) more s p e c i e s  the  o r members o f two o r  at the same t r o p h i c l e v e l ( i n t e r s p e c i f i c )  common r e s o u r c e t h a t i s a c t u a l l y o r p o t e n t i a l l y  for a  limiting"  ( M i l l e r 1967). O r , i n the words o f C l e m e n t s , Weaver and Hanson ( 1 9 2 9 ) , " . . . w h e n the immediate s u p p l y o f a s i n g l e factor  f a l l s below the combined demands o f the  necessary  plants  c o m p e t i t i o n b e g i n s . " The s i t u a t i o n i s p o t e n t i a l l y f a i r l y i n green p l a n t s .  They compete f o r the common r e s o u r c e s :  simple light,  128 water, mineral n u t r i e n t s ,  and (sometimes)  p o l l i n a t o r s and  d i s p e r s a l agents. The n i c h e concept and c o m p e t i t i o n t h e o r y have been n e a t l y combined i n the s o - c a l l e d " c o m p e t i t i v e e x c l u s i o n p r i n c i p l e " (Cole I 9 6 0 ; H a r d i n 1960; P a t t e n 1961; DeBach 1966) t h a t t h a t no two s p e c i e s can c o - e x i s t i n d e f i n i t e l y i f t h e i r  states niches  are i d e n t i c a l . Though the p r i n c i p l e o f c o m p e t i t i v e e x c l u s i o n i s h i g h l y c o n t r o v e r s i a l (at l e a s t  s y n t a c t i c a l l y ) , a common  sense c o r o l l a r y i s t h a t c o m p e t i t i o n promotes n i c h e d i f f e r e n t i a t i o n ( W h i t t a k e r 1967, 1970a; M c i n t o s h 1970). S p e c i e s w i l l t o e v o l v e away from d i r e c t c o m p e t i t i o n where one o r more is  at a s e l e c t i v e  tend species  disadvantage.  Recent e c o l o g i c a l t h e o r y (Dobzhansky 1950; Odum 1969; S l o b o d k i n and Sanders 1969; Baker 1970) has i t t h a t n i c h e s p e c i a l i z a t i o n of species i n "soft"  and/or p r e d i c t a b l e p h y s i c a l  environments w i l l be more h i g h l y developed than i n h a r s h  and/or  unpredictable environments.  first  type of species Pauciversant  B e n n i n g h o f f (19 69) c a l l s the  "pauciversant";  the s e c o n d ,  "multiversant".  s p e c i e s are s a i d t o have narrower n i c h e s and t h i s  i s probably t r u e ,  s i n c e communities o f p a u c i v e r s a n t  more d i v e r s e (Baker 1970) and the i n c r e a s e d c o m p e t i t i o n accompanied by r e s o u r c e  species  interspecific  s p e c i a l i z a t i o n should  reduce the s i z e o f b o t h the r e a l i z e d and fundamental  niche.  M u l t i v e r s a n t s p e c i e s are b e l i e v e d t o have l a r g e n i c h e s t h a t o p t i m a l i n u n c e r t a i n environments  are  are  ( L e v i n s 1968).  Dominance can be d e f i n e d as "the a p p r o p r i a t i o n o f p o t e n t i a l n i c h e space of c e r t a i n s u b o r d i n a t e species"  s p e c i e s by o t h e r  dominant  (McNaughton and Wolf 1970). As w i t h c o m p e t i t i o n ,  129 dominance i s b e s t m a n i f e s t e d  w i t h i n a t r o p h i c l e v e l . There  two a s p e c t s t o a d i s c u s s i o n o f dominance and the n i c h e :  are  the  s i t u a t i o n as i t e x i s t s w i t h i n a p a r t i c u l a r community, and any p a t t e r n s t h a t may e x i s t between d i f f e r e n t  communities.  The  f o l l o w i n g d i s c u s s i o n owes much t o the papers o f M c i n t o s h (1970) and McNaughton and Wolf  (1970).  W i t h i n a community, the more abundant, dominant w i l l experience  a h i g h degree o f i n t r a s p e c i f i c  species  competition.  T h i s w i l l tend t o generate i n d i v i d u a l homozygosity and population heterogeneity. experience  increased  Less abundant, s c a t t e r e d s p e c i e s  i n t e r s p e c i f i c competition; this w i l l  to i n d i v i d u a l heterozygosity either  will lead  and p o p u l a t i o n homogeneity.  In  c a s e , the degree of i n d i v i d u a l or p o p u l a t i o n v a r i a b i l i t y  w i l l depend on the r e l a t i v e amounts o f i n b r e e d i n g and strength of  the  selection.  Evidence t h a t i n t r a s p e c i f i c competition creates g r e a t e r i n t r a p o p u l a t i o n a l v a r i a b i l i t y w i t h i n the competing p l a n t  species  than does i n t e r s p e c i f i c c o m p e t i t i o n comes from the work o f J a i n (1969) and J a i n and M a r s h a l l ( 1 9 6 7 ) . They found t h a t , i n u s i n g the degree of ^ g e n e t i c • p61ymorphi:smaa s .measured  Avena,  -  terms o f g e n o t y p i c f r e q u e n c i e s two s p e c i e s  in  o f marker l o c i , pure stands o f  showed more i n t r a s p e c i f i c v a r i a t i o n t h a n mixed,  stands. E v i d e n t l y i n t e r s p e c i f i c competition r e s u l t s i n tighter  n i c h e s p e c i a l i z a t i o n and reduces b i o t y p e  diversity.  Moreover, c o m p e t i t i o n a s i d e , the more abundant, species  dominant  s h o u l d have g r e a t e r v a r i a b i l i t y i n p a r t because  larger populations  their  are l i k e l y t o c o n t a i n more b i o t y p e s , and i f  they have b r o a d e r l i m i t s o f t o l e r a n c e  they w i l l a l s o have  130 greater phenotypic v a r i a b i l i t y than subordinate s p e c i e s .  This  phenotypic- v a r i a b i l i t y i s l i k e l y t o have a l a r g e g e n e t i c component (Bradshaw 1972). W i t h i n a community, t h e n , the dominant s p e c i e s s h o u l d have l a r g e r n i c h e s ( L e v i n s 196 8; McNaughton and Wolf  1970).and  c o n c o m i t a n t l y g r e a t e r p o p u l a t i o n h e t e r o g e n e i t y and m o r p h o l o g i c a l variability  (Van V a l e n ,196 5 ;'• Van V a l e n et al. 1970) t h a n  s u b o r d i n a t e s p e c i e s . To t e s t t h i s h y p o t h e s i s i t i s  necessary  t o have a v a l i d measure o f n i c h e w i d t h o r s i z e . McNaughton and Wolf's  (1970) measure s i m p l i f i e s t o z e r o i f t h e r e i s o n l y one  community f o r each s p e c i e s , as i s the case i n t h i s s t u d y . So I must use L e v i n s ' log  (19 68) measure:  B = -Epilog  p  ±  where p^ i s the p r o p o r t i o n o f t h e s p e c i e s i n community i , and If  B i s a measure o f n i c h e s i z e .  t h e r e i s o n l y one community f o r each s p e c i e s , the n i c h e  s i z e of a p a r t i c u l a r s p e c i e s w i l l merely be i t s p r o p o r t i o n o f the t o t a l importance o f a l l s p e c i e s i n i t s community; i . e . , i n the f o l l o w i n g examples, n i c h e s i z e w i l l be approximated by importance v a l u e s . To i n v e s t i g a t e the r e l a t i o n s h i p between n i c h e s i z e and morphological v a r i a b i l i t y , populations of nine species of g r a s s e s t h a t grow i n t h e study communities were sampled and scored f o r f o u r p h e n e t i c c h a r a c t e r s .  The c h a r a c t e r s were p l a n t  height, inflorescence length, flag leaf of  l e n g t h , and the number  s p i k e l e t s p e r i n f l o r e s c e n c e . These c h a r a c t e r s were chosen i n  p a r t because o f precedent measurement,  ( J a i n and M a r s h a l l 1967) and ease o f  and p a r t l y because the f i r s t and t h i r d  are  131 v e g e t a t i v e and t h e second and f o u r t h presumably are characters.  reproductive  F l a g l e a f l e n g t h may not be as i n c i d e n t a l a  c h a r a c t e r as i t seems, s i n c e C a r r and Wardlaw (19 65) have demonstrated  t h a t as much as 50% o f the carbon f i x e d by the  f l a g l e a f goes t o f r u i t  production.  Table 16 summarizes the s t a t i s t i c s .  The c o e f f i c i e n t o f  v a r i a t i o n (CV) i s s i m p l y the s t a n d a r d d e v i a t i o n expressed as a p e r c e n t a g e o f the mean; v i z . , CV = s x 100/ Y ( S o k a l and R o h l f  1969).  T h i s s t a t i s t i c may be used t o compare v a r i a b i l i t y i n p o p u l a t i o n s h a v i n g w i d e l y d i f f e r e n t means o f m e r i s t i c  characters.  TABLE 16. M o r p h o l o g i c a l v a r i a t i o n i n n i n e g r a s s s p e c i e s . C o e f f i c i e n t s of v a r i a t i o n for p l a n t height ( C V i ) , inflorescence length ( C V ) , flag leaf length ( C V ) , and number o f s p i k e l e t s per i n f l o r e s c e n c e (CVi+K 2  Species  Pueoinellia pumila Agrostis exarata Festuoa rubra Des c h a m p s i a oespitosa Agrostis aequivalvis Poa c u s i o k i i T r i s etum spioatum Phleum alpinum Festuoa viridula  Importance Value  Sample size  3  CV  l  CV  2  CV  3  CV  it  ECV  2.7  35  0. 29  0. 17  0. 26  0. 28  1. 00  7.2  69  0. 22  0. 26  0. 37  0. 45  1. 30  24. 5 38 . 6  61 55  0. 28 0. 26  0. 30 0. 28  0. 39 0. 56  0. 49 0. 52  1. 46 1. 63  15 . 9  103  0. 18  0. 23  0. 32  0 . 39  1. 11  1.9 3. 2  64 60  0. 18 0. 17  0. 20 0. 18  0. 21 0. 31  0. 20 0. 23  0. 80 0. 89  4.8 24. 3  66 53  0. 22 0. 16  0. 19 0. 20  0. 34 0. 48  0. 28 0. 36  1. 03 1. 20  132 F i g u r e 15 0 i l l u s t r a t e s the r e l a t i o n s h i p between  abundance  and v a r i a b i l i t y o f f o u r s p e c i e s o f g r a s s e s from the s a l t marsh and f o u r from the s u b a l p i n e meadow (.Agrostis  o n l y g r a s s i n the sphagnum b o g s ) . The sum o f the of  v a r i a t i o n for a l l four characters  (ECVi-it)  is  aequivalvis  coefficients  has been p l o t t e d  a g a i n s t the l o g o f importance v a l u e f o r each s p e c i e s . the most abundant  the  Clearly,  s p e c i e s are a l s o the most v a r i a b l e , as was  p r e d i c t e d from t h e o r y . Niche s i z e comparisons between communities are  also  i n f o r m a t i v e , though h i g h l y s p e c u l a t i v e . F o l l o w i n g McNaughton and W o l f ' s  (197 0) l o g i c , whereby the t o t a l amount of n i c h e  space a v a i l a b l e t o t h e p l a n t s i n a g i v e n community i s approximated by the sum o f i t s  individual species'  importances,  it  i s c l e a r from T a b l e s 2-5 t h a t t h i s p l a n t " c a r r y i n g c a p a c i t y "  is  about the same f o r a l l f o u r c o m m u n i t i e s , p r o v i d e d sphagnum  moss i s i n c l u d e d i n the t o t a l o f bog v e g e t a t i o n c o v e r . T h i s b e i n g s o , the average n i c h e s i z e s h o u l d d e c r e a s e from S a l t Marsh t o Wade's Bog t o Ogg's Bog t o B l a c k w a l l Meadow, s i n c e the number o f s p e c i e s  increases  i n t h a t o r d e r . As more  species  are added t o a p l a n t community, i n t e r s p e c i f i c c o m p e t i t i o n and n i c h e s p e c i a l i z a t i o n s h o u l d i n c r e a s e , r e s u l t i n g i n narrower p h y s i o l o g i c a l l i m i t s o f t o l e r a n c e and s m a l l e r n i c h e s , b o t h fundamental and r e a l i z e d . There i s some e v i d e n c e f o r t h e h y p o t h e s i s t h a t s p e c i e s o f h a r s h environments have l a r g e r fundamental n i c h e s . latifolia  Typha  i s a w i d e l y d i s t r i b u t e d s p e c i e s t h a t i s u s u a l l y much  more abundant  t h a n T. a n g u s t i f o l i a ,  r e s t r i c t e d to s a l i n e h a b i t a t s  a species  generally  ( S m i t h 1 9 6 7 ) . Experiments on s a l t  CO CO  8  Fig.  15'p). Log o f importance v a l u e v s . the sum o f c o e f f i c i e n t s morphological characters. TSP - T r i s e t u m FRU  - Festuca  spicatum; rubra;  FVI - F e s t u c a  viridula;  PEP - Poa c u s i c k i i ;  AEX - A g r o s t i s  exarata;  of v a r i a t i o n f o r  PAL - P h l e u m  DCS - D e s c h a m p s i a PPU - P u c c i n e l l i a  BM - mean o f s u b a l p i n e meadow g r a s s e s ; AAE - A g r o s t i s  mean o f s a l t marsh g r a s s e s .  four  alpinum; cespitosa pumila;  aequivalvis;  SM -  133 h  HfllVA  33NVlcJ0dWI  tolerance  ( M c M i l l a n 19 59) i n d i c a t e , however, t h a t T.  can s u r v i v e i n b o t h f r e s h and s a l t w a t e r , whereas T.  folia  can occupy o n l y f r e s h water s i t e s .  latifolia  T h u s , T.  a l t h o u g h i t has broader l i m i t s o f t o l e r a n c e ,  folia, in  abundance by i t s p o o r e r c o m p e t i t i v e a b i l i t y  and i n t e r p r e t a t i o n s  restricted  (McNaughton and  (see C o n n e l l 1972) f o r competing  b a r n a c l e s and o t h e r i n t e r t i d a l i n v e r t e b r a t e s .  angusti-  is  Wolf 1970). C o n n e l l ' s (19 61) work has y i e l d e d s i m i l a r  of  134 angusti-  results species  So t h e  dominant  s a l t marsh and bog s p e c i e s may be viewed as b r o a d - n i c h e d but r e s t r i c t e d to t h e i r respective habitats competitive a b i l i t y . species  by r e l a t i v e l y poor  T h i s has been the t r a d i t i o n a l view o f bog  (Gorham 1953, 1957; Heinselman 1963) and e v i d e n c e t h a t  many s a l t marsh s p e c i e s can grow as w e l l in, fresh.'water as in. i s a l t water c(if 1959;  ;  not  better.) has been a c c u m u l a t i n g ( M c M i l l a n :  Adams 1963; S t a l t e r and B a t s o n 1969; Barbour 1970;  Barbour and D a v i s 1970; C l a r k e and Hannon 197 0; P h l e g e r 1971; W a i s e l 1972). In  c o n j u n c t i o n w i t h t h e above e v i d e n c e , note t h a t ( F i g .  150) g r a s s e s o f B l a c k w a l l Meadow are l e s s v a r i a b l e t h a n g r a s s e s of  comparable importance v a l u e i n the S a l t M a r s h . U n f o r t u n a t e l y ,  t h e r e i s o n l y one g r a s s s p e c i e s i n the sphagnum b o g s , aequivalvis,  but i f i t i s t a k e n t o be r e p r e s e n t a t i v e  t h a t v a r i a b i l i t y i s , on the a v e r a g e ,  least  Agrostis it  appears  i n s u b a l p i n e meadow  g r a s s e s (see d o t t e d l i n e t h r o u g h SM, A A E , and BM i n F i g . 1 5 0 ) . T h i s would be expected i f indeed average n i c h e s i z e d e c r e a s e s from s a l t marsh t o sphagnum bog to s u b a l p i n e meadow. V a r i a b i l i t y i n populations of plant species i s profoundly a f f e c t e d by the s p e c i e s '  b r e e d i n g systems, which have so f a r  135 been o v e r l o o k e d i n t h i s d i s c u s s i o n . T h e o r e t i c a l l y , self-fertilization 1957a)  predominant  s h o u l d reduce p o p u l a t i o n . v a r i a b i l i t y  and t h e o r y has i n many cases been borne out  (Stebbins  (eg.,  Atsatt  and S t r o n g 197 0; S o l b r i g 1 9 7 2 ) . However, some i n b r e e d i n g s p e c i e s have m a i n t a i n e d a h i g h l e v e l o f p o p u l a t i o n v a r i a b i l i t y , presumably t h r o u g h o c c a s i o n a l i n t e r - and  intrapopulational  o u t c r o s s i n g between s t r o n g l y homozygous b i o t y p e s  (Allard  A l l a r d , J a i n and Workman 1967; J a i n and M a r s h a l l 1967;  1965;  Rollins  1967; J a i n , M a r s h a l l and Wu 1 9 7 0 ) . Of Agrostis  the n i n e s p e c i e s exarata,  of grasses, four  Trisetum  spicatum,  s e l f - i n c o m p a t i b l e and n e c e s s a r i l y Festuca  aequivalviSj  viridula,  p a r t i a l l y self-compatible moderately  and F e s t u c a  cespitosa,  rubra)  strongly outcrossed.  and P h l e u m a l p i n u m  are at  pumila  i s self-compatible  w h i l e Poa cusickii  is  CV average h i g h e r f o r the f o u r s e l f - i n c o m p a t i b l e but the d i f f e r e n c e  case s i g n i f i c a n t a c c o r d i n g t o a t - t e s t cusickii  1946-47).  species  total than  i n means i s i n no  i s o v e r a l l the l e a s t v a r i a b l e s p e c i e s .  (Gustafsson  and  (P > 0 . 0 5 ) . A l s o , Poa  p o p u l a t i o n v a r i a b i l i t y i s t o be expected species  least  the  o f v a r i a t i o n f o r a l l f o u r c h a r a c t e r s and the  the o t h e r f i v e s p e c i e s ,  Agrostis  agamospermous;  both must be h i g h l y i n b r e d . T a b l e 16 i n d i c a t e s t h a t coefficients  are  and though w i n d - p o l l i n a t e d p r o b a b l y  i n b r e d . Puccinellia  p a r t i a l l y cleistogamous  (Deschampsia  Low w i t h i n -  i n agamospermous  136 H.  Niche d i f f e r e n t i a t i o n .  N u m e r i c a l taxonomy o f f e r s  an approach to the study o f  n i c h e d i f f e r e n t i a t i o n w i t h i n p l a n t communities. Assuming t h a t quantitative  o r q u a l i t a t i v e m o r p h o l o g i c a l and b e h a v i o r a l  c h a r a c t e r s are o f e c o l o g i c a l s i g n i f i c a n c e i n the l i f e o f it  plants,  s h o u l d be p o s s i b l e t o q u a n t i f y the e c o l o g i c a l s i m i l a r i t i e s  or d i s s i m i l a r i t i e s o f a group o f s p e c i e s t h a t  characteristically  grow t o g e t h e r . For example, a Festuca  is  species  phenetically  more l i k e a Deschampsia  than a P o t e n t i l l a ,  more l i k e a R a n u n c u l u s ,  an A n e m o n e , or an A r n i c a , e c o l o g i c a l l y  speaking? T a x o n o m i c a l l y , t h e s e q u e s t i o n s and the e c o l o g i c a l answers  but i s a  are easy to  Potentilla  answer,  s h o u l d be s i m i l a r , s i n c e a s p e c i e s  s h o u l d be an e c o l o g i c a l u n i t as w e l l as a t a x o n . But an ecological s i m i l a r i t y analysis could offer interesting perhaps s u r p r i s i n g i n s i g h t s . What s p e c i e s  i n the  subalpine  meadow i s e c o l o g i c a l l y most s i m i l a r t o Thalictrum Does Gentiana  douglasiana  or Trientalis  arctica  and  occidentalel  f u n c t i o n more l i k e Gentiana i n the sphagnum bogs? I w i l l t r y  answer t h e s e and s i m i l a r q u e s t i o n s d e s c r i p t i o n o f each s p e c i e s '  sceptrum to  by what amounts t o a p a r t i a l  niche, necessarily using only  t h o s e c h a r a c t e r s t h a t are e a s i l y measured or observed and unfortunately  omitting p h y s i o l o g i c a l niche  components.  The approach has been neo-Adansonian whereby e q u a l weight is  g i v e n t o a l l c h a r a c t e r s used i n the a n a l y s i s . A s i m i l a r i t y  measure f o r mixed q u a n t i t a t i v e  and q u a l i t a t i v e  attributes  (Anderson 1971) has been u s e d . A n d e r s o n ' s measure of s i m i l a r i t y is  as  follows.  137 If attribute  k i s q u a n t i t a t i v e and s c a l e d t o have a p p r o x i -  mately u n i t range, l e t  .  fe  =  x  ik jk x  I f a t t r i b u t e A: i s q u a l i t a t i v e , l e t 0 s  w  =  13 k  h  e  n  *ih * * j k  0.5 when x ^ T  h  e  n  1 m S. . = - Z S. , 13  m  = x  7  13k  where S . . i s the s i m i l a r i t y between o p e r a t i o n a l taxonomic 13  u n i t s (OTU's) . . and m the t o t a l number o f a t t r i b u t e s .  The  d i s t a n c e d . . between O T U ' s . . i s t h e n computed as 13  13  ^  d . . = (s . . + s . . - 2 s . . ) 13  ii  33  1 / 2  .  13  The OTU's f o r each community are i t s c o n s t i t u e n t A t o t a l o f 32 u n i t c h a r a c t e r s were used t o measure  species.  similarity  between OTU's. A u n i t c h a r a c t e r i s d e f i n e d by S o k a l and Sneath (19 63) as a "taxonomic c h a r a c t e r o f two or more s t a t e s , which w i t h i n the study at hand cannot be s u b d i v i d e d l o g i c a l l y ,  except  f o r s u b d i v i s i o n brought about by changes i n the method o f c o d i n g " . Each u n i t c h a r a c t e r has a t l e a s t two s t a t e s . I have t r i e d t o choose independent c h a r a c t e r s but f o r the sake o f completeness some redundancy was u n a v o i d a b l e . The u n i t  characters  are o u t l i n e d i n T a b l e 17 and ( i f n e c e s s a r y ) e x p l a i n e d i n the following  paragraphs.  The l i f e - f o r m c l a s s i f i c a t i o n  i s adopted from R a u n k i a e r  (.1934). Therophytes are annuals i n which the r e n e w a l bud i s w i t h i n the seed c o a t . Geophytes have p e r e n n a t i n g buds covered by s o i l , whereas the buds o f h e m i c r y p t o p h y t e s are a t or s l i g h t l y embedded i n the s o i l s u r f a c e .  Chamaephytes are  138 TABLE 17. E c o l o g i c a l u n i t  Unit  character  characters.  Character states  Number o f  therophyte geophyte hemicryptophyte chamaephyte nanophanerophyte  5  2. organ o f perennation  seed o n l y corm, t u b e r , o r b u l b b a s a l bud caudex rhizome bud stem bud  6  3. r o o t system  taproot fascicled fibrous  3  4. stem form  erect decumbent or matted acaulescent  3  5. stem c o v e r i n g  g l a b r o u s or s l i g h t l y pubescent moderately to densely p u b e s c e n t , tomentose, v i l l o u s , etc. glandular-pubescent glandular  4  6. l e a f size  leptophyll nanophyll microphyll mesophyll macrophyll  5  7. g r a s s , sedge, o r rush leaf width (at widest p o i n t )  l e s s t h a n 4 mm g r e a t e r t h a n 4 mm does not a p p l y  3  8. l e a f  more or l e s s p l a n a r t e r e t e or i n v o l u t e  2  1.  life-form  (leaflet)  form  states  139 TABLE 17.  Unit  (Continued)  character  Character states  Number of  basal rosette h o r i z o n t a l (0-15 ) i n one p l a n e horizontal i n several planes angled v e r t i c a l (70 o r more)  5  10. l e a f margin  entire-serrate lobed-incised dissected-compound  3  11. l e a f  persistence  deciduous evergreen  2  12. l e a f  texture  membranous coriaceous (leathery) cartilaginous fleshy or succulent  4  13. l e a f c o v e r i n g  glabrous or s l i g h t l y pubescent moderately t o d e n s e l y p u b e s c e n t , tomentose, v i l l o u s , etc. glandular-pubescent glandular  4  14. growth form  s i n g l e , unbranched 3 f r e e l y branched, rhizomatous or spreading cespitose or clump-forming  15.  rhizome stolon vivipary none  9. l e a f  display  Q  vegetative propagation  16. t e m p o r a l s e p a r a t i o n homogamy of s e x u a l f u n c t i o n s weak dichogamy moderate dichogamy s t r o n g dichogamy monoecy dioecy  4  6  states  140 TABLE 17.  Unit  (Continued)  character  Character  states  Number of  17. p o l l i n a t i o n mechanism  predominantly s e l f p o l l i n a t i o n or cleistogamy anemophily by muscid f l i e s by s y r p h i d f l i e s by bee f l i e s by s m a l l , s h o r t tongued bees by bumble bees by b u t t e r f l i e s by hawk moths by ants by b e e t l e s by hummingbirds  12  18. f l o w e r c o l o r  flowers inconspicuous greenish white pink orange red lavender purple blue yellow  10  19. f l o w e r  faint moderate strong none  4  20. f l o w e r odor  faint moderate strong none  4  21. f l o w e r  amorphic haplomorphic actinomorphic pleomorphic stereomorphic zygomorpaic  6  nectarifery  type  states  141  TABLE 17. (Concluded)  Unit  Character  character  Number o f s t a t e s  states  22*  propagule.-type  auxochore cyclochore pterochore pogonochore desmochore sarcochore sporochore microsclerochore megasclerochore ballochore  23.  dispersal mechanism  anemochory hydrochory epizoochory endozoochory autochory  5  24.  plants  +•/-  2  25.  p l a n t s r o o t " •„ p a r a s i t e s . . •_.. -  + /-  2  + /-  2  0.2 0.4 0.6 0.8 1.0  5  carnivorous .  26.  plants  27.  e s t i m a t e o f degree of v e g e t a t i v e propagation  28.  average h e i g h t o f f.lower o r i n f l .  29.  average w i d t h of flow infl. e r  ^-fixing  o  10  i  n  l  n  2  n  3  n  4  n  5  r  30.  average l e n g t h o f f l o w e r or i n f l .  31.  t i m e of  32.  length of  flowering flowering Total  124 +  5 In 1  142 p r o s t r a t e p l a n t s o r low shrubs w i t h buds above t h e s o i l ,  but  not over 2 5 cm above. Nanophanerophytes bear t h e i r buds between 0.25 and 2 m above the s u r f a c e .  The l i f e - f o r m g e n e r a l l y  follows  from the organ of p e r e n n a t i o n , but not n e c e s s a r i l y . For i n s t a n c e , Junous  balticus  i s r h i z o m a t o u s but i s c l a s s e d as a  geophyte (Clapham, T u t i n and Warburg 1 9 6 2 ) . H e m i c r y p t o p h y t e s may perennate by means o f a b a s a l b u d , a rhizome b u d , o r a caudex. The caudex i s understood here as the woody, base o f an o t h e r w i s e a n n u a l herbaceous  stem, as i n  persistent Castitleja  miniata.  The l e a f o r l e a f l e t s i z e c l a s s e s are a l s o t a k e n from R a u n k i a e r ( 1 9 3 4 ) . H i s c l a s s i f i c a t i o n i s as  follows:  2 l e p t o p h y l l s - area s m a l l e r than 2 5 mm 2 nanophylls  - 25 - 225 mm  m i c r o p h y l l s - 225 - 2,025 mm  2  mesophylls  - 2,025 - 18,225 mm  2  m a c r o p h y l l s - 18,2 25 - 164,025 mm  2  The f u r t h e r d i s t i n c t i o n between g r a m i n o i d l e a v e s w i d e r o r narrower than 4 mm f o l l o w s K n i g h t  (1965).  The t y p o l o g i c a l c l a s s i f i c a t i o n o f f l o w e r s i s t h a t o f L e p p i k (1957, 1968a S b ) , who d e s c r i b e d them as s u c c e s s i v e l e v e l s i n the g e n e r a l t r e n d o f f l o r a l e v o l u t i o n . Whether L e p p i k ' s phylogeny i s v a l i d o r not i s not p e r t i n e n t h e r e ;  the  f l o r a l types seem t o be e c o l o g i c a l t y p e s as w e l l , i n g e n e r a l e x p l o i t i n g d i f f e r e n t groups o f a n i m a l p o l l i n a t o r s . The s i x types are: amorphic, haplomorphic, a c t i n o m o r p h i c , pleomorphic, s t e r e o m o r p h i c , and zygomorphic. Amorphic f l o w e r s  are  supposedly p r i m i t i v e c l u s t e r s o f d i s c o l o r e d l e a v e s w i t h o u t  143 p a r t i c u l a r form. Haplomorphic t y p e s are c h a r a c t e r i z e d by many separate flower parts frequently  s p i r a l l y arranged.  Actino-  morphic t y p e s c o n s i s t o f p o l y p e t a l o u s f l o w e r s w i t h t h e i r flattened  parts  i n t o more or l e s s one p l a n e . P l e o m o r p h i c f l o w e r s  are  s i m i l a r t o a c t i n o m o r p h i c f l o w e r s but have c e r t a i n s y m m e t r i c a l numerate p a t t e r n s o f p a r t s ;  eg., t r i - , tetra-,  or  pentamery.  Stereomorphic f l o w e r s are t h r e e - d i m e n s i o n a l and u s u a l l y have some s o r t o f f l o r a l t u b e .  Zygomorphic t y p e s are the h i g h l y  s p e c i a l i z e d f l o w e r s w i t h b i l a t e r a l symmetry and concealed nectar.  frequently  S p e c i e s o f Compositae, s u b f a m i l y T u b i f l o r a e  must be s c o r e d p o s i t i v e f o r b o t h zygomorphic and  stereomorphic  f l o w e r s , a n d , as the c a p i t u l u m i s p r o b a b l y the u n i t o f  insect  p e r c e p t i o n , a l s o s c o r e d p o s i t i v e f o r , s a y , actinomorphy i n the case o f A r n i c a  spp. , or pleomorphy i n A c h i l l e a  O b s e r v a t i o n s o f f l o w e r c o l o r and odor are  millefolium.  necessarily  human and s u b j e c t i v e . However, a n i m a l s (most i m p o r t a n t l y insects)  seem t o respond to the same s m e l l s as man, but  sense o f s m e l l i s g e n e r a l l y k e e n e r , s i g n a l the presence  e s p e c i a l l y for scents that  of food o r s e x u a l p a r t n e r s (Free 19 7 0 a ;  Kugler. 1970.; : F a e g r i and van der P i j l  1971; F r i s c h 1971).  S i m i l a r l y , t h e v i s u a l range o f t h e spectrum i n t h e most a n i m a l p o l l i n a t o r s does not d i f f e r much from m a n ' s , t h e r e i s a s h i f t towards s h o r t e r wavelengths der P i j l  their  important  although  ( F a e g r i and van  1971). Bees can d i s t i n g u i s h f o u r c o l o r g r o u p s :  yellow,  b l u e - g r e e n , b l u e , and u l t r a v i o l e t , but not r e d ( F a e g r i and van der P i j l  1971).  However,- f l o w e r s c o u l d not be s c o r e d f o r  presence  o f u l t r a v i o l e t n e c t a r guides , which a r e i n v i s i b l e  humans but appear t o be f a i r l y common i n some  the  angiospermous  to  144 groups  (Daumer 1958;  O r n d u f f and The  Lindauer  Mosquin  previously propagule  i n Table  redundancy  13.  and  a n a l y s i s , but inferred  species  rotundif'olia.  Pedioularis  braoteosa,  C.  are  1 9 6 9 ) . Trifolium are  the  the  Character  a l l possible  are  a l l presented interest  the  as are  Ranges o f v a l u e s  morphology.  study  Drosera  is  documented r o o t  parasites  latifolius,  to  and  (Kuijt Myrioa  and  nitrogen-fixing root e a c h OTU  ecological distance  species  a c t u a l mode  miniata,  s t a t e s were a s s i g n e d  for  Salt  in this  for  some  Castilleja  species with  e a c h community, and  general  only  f r e q u e n t l y the  wormskjoldiiLupinus  three  categories  from d i a s p o r e  carnivorous  parviflora  outlined  d i s p e r s a l mechanisms i n t r o d u c e  i n t o the  only  1969;  morphological  (1970) and  Undoubtedly, separate  o f d i s p e r s a l c a n n o t be The  i s a simple  adopted from F r e n k e l  types  al.  1970).  scheme o f p r o p a g u l e t y p e s  classification  gale  E i s n e r et  1967;  nodules.  (species)  (.d)  calculated  p a i r s w i t h i n a community. T h e s e  part  of Appendix  discussed for d  3, b u t  of  some p o i n t s  d's of  below.  (0<_d<_l)  are:  Marsh  0.25  (DCSxppu)  0.62  (TW0*SCA)  Wade's Bog  0.15  (RALxSCS)  0.63  (COBxVVI)  Ogg's Bog  0.14  (RALxSCS)  0.63  (COBxVVI)  Blackwall  0.19  (VSCxVDE)  0.62  (PDIxVVD)  Meadow The  most e c o l o g i c a l l y  species with Spergularia idaea  the  highest  canadensis  i n b o t h b o g s , and  distinctive  species  (i.e.,  the  a v e r a g e e c o l o g i c a l d i s t a n c e , d)  i n the Veratrum  salt  m a r s h , Vaooinium  viride  i n the  are vitis-  subalpine  meadow.  The average e c o l o g i c a l d i s t a n c e a g i v e n community i s 0 . 4 6 ,  0.54,  145 (d) b e t w e e n • a i i - s p e c i e s . o f  0 . 5 2 , and 0.49 f o r the  Salt  M a r s h , Wade's B o g , Ogg's B o g , and B l a c k w a l l Meadow, r e s p e c t i v e l y . That i s to" s a y , s a l t marsh s p e c i e s a r e ,  on the a v e r a g e ,  most e c o l o g i c a l l y e q u i v a l e n t and sphagnum bog s p e c i e s e c o l o g i c a l l y d i s t i n c t i v e , according to t h i s  the  most  analysis.  I have t r i e d t o f i t t h e s e community d's scheme o f t h i s  the  i n t o the  general  i n v e s t i g a t i o n i n F i g . 151. To get some i n d i c a t i o n  o f the r e l a t i v e s t r e n g t h s o f i n t e r s p e c i f i c c o m p e t i t i o n w i t h i n the d i f f e r e n t  c o m m u n i t i e s , I have c a l c u l a t e d f o r each  p r o d u c t o f average v a s c u l a r p l a n t cover (C) times the  the absolute  v a l u e o f t h e average community c o r r e l a t i o n c o e f f i c i e n t times the community s p e c i e s d i v e r s i t y ( # ' ) ( s e e S e c t . I have p l o t t e d t h i s product a g a i n s t ecological difference  (|r|) III-I).  the average community  or d i s t i n c t i v e n e s s  ( d ) . My i n t e r p r e t a t i o n  of F i g . 151 i s t h a t i t r e p r e s e n t s a p o r t i o n o f a p o t e n t i a l a r e a upon which a l l v e g e t a t i o n t y p e s (or s t r a t a t h e r e o f ) w o r l d c o u l d be p l o t t e d , i f s u b j e c t e d upper l e f t o f t h i s f i g u r e  i n the  t o s i m i l a r a n a l y s i s . The  (strong e c o l o g i c a l s i m i l a r i t y , strong  i n t e r s p e c i f i c c o m p e t i t i o n ) might r e p r e s e n t the s i t u a t i o n i n a s t r a t u m of t r o p i c a l r a i n f o r e s t community; the lower r i g h t  v e g e t a t i o n or a c h a p a r r a l  shrub  ( e c o l o g i c a l d i s s i m i l a r i t y , weak  c o m p e t i t i o n ) b y , f o r example, sphagnum bogs and Sonoran d e s e r t ; the lower l e f t  ( e c o l o g i c a l s i m i l a r i t y , weak c o m p e t i t i o n ) by  h i g h s a l i n i t y s a l t marshes,  c o l d d e s e r t s ( e g . , Great B a s i n )  and a r c t i c and a l p i n e t u n d r a ; the upper r i g h t dissimilarity,  (ecological  s t r o n g c o m p e t i t i o n ) by t a l l g r a s s p r a i r i e .  146  cu  F i g . 151.  S t r e n g t h of i n t e r s p e c i f i c c o m p e t i t i o n v s . average ecological  distinctiveness.  100  chaparral shrubs? rain forest  95  t a l l grass prairie?  » Blackwall Meadow  stratum?  M  90 85 80 475 70 65 60  S a l t Marsh  55  Great Basin desert?  50  Sonoran desert?  45 Wade's Bog  40  Ogg's Bog  35 30  0.44  H 0.45 .0.46  h H h 0.47 0.48 0.49 0.50 0.51 0.52 0.53 0.54 0.55 0.56 0.57 ^» d  (AVERAGE ECOLOGICAL  DISTINCTIVENESS)  0.58  147 F u r t h e r a n a l y s i s o f the d's  i n Appendix 2 c o r r o b o r a t e s  some o f the s p e c u l a t i o n s made i n the d i s c u s s i o n ( i n S e c t .  III-B)  on i n t e r s p e c i f i c c o r r e l a t i o n . I n the b o g s , d between a l l g r a s s e s and g r a s s - l i k e s p e c i e s i s about 0 . 3 4 ; between a l l s h r u b s , I n t h e s u b a l p i n e meadow, d f o r a l l g r a m i n o i d s i s 0 . 3 5 ;  for  Compositae, 0 . 3 9 . Thus, as suggested p r e v i o u s l y , t h e r e  is  g r e a t e r n i c h e d i f f e r e n t i a t i o n among the shrubs i n t h e  0.45.  bogs  and the meadow composites t h a n among t h e g r a m i n o i d s p e c i e s , and t h i s a p p a r e n t l y r e s u l t s g r a s s e s and g r a s s - l i k e  i n stronger  c o m p e t i t i o n among  plants.  One f i n a l p o i n t : i f v i s a measure o f i n t e r s p e c i f i c c o m p e t i t i o n , and d of e c o l o g i c a l s i m i l a r i t y , a n d , f u r t h e r , the most d i s s i m i l a r s p e c i e s compete the l e a s t converse i s t r u e ) ;  if  (and i f the  t h e n t h e r e s h o u l d be a p o s i t i v e c o r r e l a t i o n  between r and d, f o r a g i v e n community. Such i s the case f o r a l l f o u r c o m m u n i t i e s . For a l l quadrat s i z e s , t h i s new r i s p o s i t i v e , though u s u a l l y weakly s o . I t s  strength  increases  if  the communities are s u b d i v i d e d i n t o a s s o c i a t i o n s ; e g . , i n the s a l t marsh, i f the s p e c i e s are put i n t o two groups vs  ;  mud f l a t s )  ( h i g h marsh  and the r computed w i t h i n t h e s e two g r o u p s ,  the v i s more p o s i t i v e t h a n i f a l l s p e c i e s are t o g e t h e r . T h i s makes s e n s e , s i n c e the e f f e c t s  grouped of i n t e r s p e c i f i c  c o m p e t i t i o n w i l l be r e f l e c t e d more r o b u s t l y by c o r r e l a t i o n c o e f f i c i e n t s between s p e c i e s t h a t c h a r a c t e r i s t i c a l l y grow t o g e t h e r i n a s s o c i a t i o n s , t h a n between s p e c i e s o f associations.  different  147 «I . Dominance, d i v e r s i t y , and s t a b i l i t y .  P l a n t communities are u s u a l l y m i x t u r e s o f u n e q u a l l y abundant  s p e c i e s t h a t form a p r o g r e s s i o n from dominant t h r o u g h  i n t e r m e d i a t e t o r a r e s p e c i e s . W i t h i n a g i v e n community i t  is  p o s s i b l e t o e s t i m a t e the s u b d i v i s i o n o f n i c h e space by assuming t h a t the importance v a l u e s o f t h e s p e c i e s c o n s t i t u t i n g the community are e x p r e s s i o n s o f t h e i r r e l a t i v e n i c h e s i z e s . I f s p e c i e s are t h e n arranged i n a sequence from most t o i m p o r t a n t and t h e s p e c i e s '  the  least  p o s i t i o n s i n t h i s sequence are  then  p l o t t e d a g a i n s t the l o g o f t h e i r r e s p e c t i v e importance v a l u e s , a c u r v e o f c h a r a c t e r i s t i c g e n e r a l form r e s u l t s  ( W h i t t a k e r 1965,  1969, 1970a). T h i s has been done f o r each o f the f o u r communities and the c u r v e s are p r e s e n t e d  study  i n F i g . 15 2A-D.  Note t h a t the c u r v e s are r o u g h l y s h a l l o w l y s i g m o i d and t h a t the s l o p e d e c r e a s e s i n o r d e r from A t o D i n the  figure.  The s i g m o i d shape r e f l e c t s the f a c t t h a t each community has a few dominant s p e c i e s and a few r a r e s p e c i e s , p l u s a l a r g e number o f s p e c i e s o f i n t e r m e d i a t e abundance. C o m p e t i t i o n t h e o r y h o l d s t h a t s p e c i e s tend t o e v o l v e toward n i c h e  different  i a t i o n and r e d u c t i o n o f i n t e r s p e c i f i c c o m p e t i t i o n , and t h e resultant-  d i v i s i o n of n i c h e space i s m a n i f e s t e d i n the  o f such d o m i n a n c e - d i v e r s i t y c u r v e s . The steepness o f the  forms curve  f o r the f l o r i s t i c a l l y poor s a l t marsh agrees w i t h W h i t t a k e r ' s o b s e r v a t i o n s t h a t s t e e p s l o p e s a r e d e r i v e d from samples o f low d i v e r s i t y communities of r i g o r o u s p h y s i c a l e n v i r o n m e n t s . The g r a d u a l moderation of the s l o p e found i n the curves the bogs and the s u b a l p i n e meadow i s c o n s i s t e n t w i t h  the  for  ' i g . 15 2. D o m i n a n c e - d i v e r s i t y c u r v e s , f o r t h e f o u r study communities.  149  i n c r e a s i n g d i v e r s i t y of these communities. The more e q u a l s u b d i v i s i o n of n i c h e space i n the communities  o f h i g h e r d i v e r s i t y i s a l s o i n d i c a t e d by a community i n d e x  of dominance, e i t h e r the DI o f McNaughton ( i n McNaughton and Wolf 1970) o r the A o f Simpson ( 1 9 4 9 ) . DI = 100(y y-^ 2 i -  s  „/Y) where  sum o f t h e importance v a l u e s o f the two most  abundant s p e c i e s  i n . the community and Y i s the t o t a l importance n 2 v a l u e o f a l l s p e c i e s i n the community; A. = ETT where TT i s the ^ 1 n  importance v a l u e o f the n t h s p e c i e s case,  n  i n the community. I n  the h i g h e r the dominance i n d e x , the g r e a t e r  c o n c e n t r a t i o n o f abundance i n the fewer s p e c i e s .  either  the Indices of  dominance f o r the four communities are l i s t e d i n T a b l e 18. The two i n d i c e s g i v e v e r y s i m i l a r r e s u l t s i n t h i s instance  and are l i n e a r l y r e l a t e d  ( F i g . 153).  TABLE 18. Number o f s p e c i e s , two i n d i c e s o f dominance, and an i n d e x of d i v e r s i t y f o r the f o u r study communities. N = number o f s p e c i e s sampled; DI = McNaughton's dominance i n d e x ; X = Simpson's dominance i n d e x ; H ' = the Shannon-Wiener i n d e x o f d i v e r s i t y .  Community  N  S a l t Marsh Wade's Bog Ogg's Bog Blackwall Meadow  18 28 41 45  DI  XxlO  H'  31.6 28. 7 27.2 24. 6  10.1 8.2 7.7 6.3  2.50 2. 71 3.03 3.13  150 a,  Fig.  153. DI (McNaughton s index of dominance), N (number of 1  s p e c i e s i n a community) v s . H' (an index o f d i v e r s i t y ) , A. (Simpson's dominance i n d e x ) .  I 1.0 0.0  1  1 1.4 0.2  1  1 1.8 0.4  1  } 2.2 0.6  1  \ 2.6 0.8  1  1  1  3.0 1.0  3.2 1.1  H'  X  151 The m a t t e r o f d i v e r s i t y r e q u i r e s f u r t h e r comment. S p e c i e s d i v e r s i t y i s a concept vague enough and o f s u f f i c i e n t l y  broad  a p p l i c a t i o n t h a t i t can be (and has been) v a r i o u s l y d e f i n e d ( c f . H u r l b e r t 1971). D i v e r s i t y i s o f t e n equated w i t h s i m p l e s p e c i e s r i c h n e s s ; i . e . , the number o f s p e c i e s p r e s e n t i n a g i v e n a r e a . However, as s t r i c t l y d e f i n e d , s p e c i e s d i v e r s i t y i s a f u n c t i o n o f the numbers o f s p e c i e s p r e s e n t ( s p e c i e s  richness)  and the evenness w i t h which the t o t a l number o f i n d i v i d u a l s ( o r t o t a l biomass) i n a community i s d i s t r i b u t e d among these s p e c i e s ( s p e c i e s e q u i t a b i l i t y ) . D i v e r s i t y and r i c h n e s s  are  u s u a l l y p o s i t i v e l y c o r r e l a t e d , but not n e c e s s a r i l y so (Johnson and Raven 1970; H u r l b e r t 1 9 7 1 ) . I n the f o u r study c o m m u n i t i e s , t h e number of s p e c i e s per community i s l i n e a r l y r e l a t e d t o  the  s p e c i e s d i v e r s i t y o f t h e s e communities ( F i g . 1 5 3 ) . D i v e r s i t y can be c a l c u l a t e d by a number o f f o r m u l a s ( M c i n t o s h 1967a; L l o y d et al. 1968; H u r l b e r t 1971; W h i t t a k e r 1972). The most commonly used i s the Shannon-Wiener i n f o r m a t i o n i n d e x , H ' = - p ^ l o g p ^ , where H ' i s the s p e c i e s d i v e r s i t y and p^ i s the p r o p o r t i o n o f i n d i v i d u a l s  (or biomass) i n the  i-th  s p e c i e s . T h i s f u n c t i o n i s d e r i v e d from i n f o r m a t i o n t h e o r y a c c o r d i n g t o the l o g i c t h a t , s i n c e d i v e r s i t y i s a f u n c t i o n o f the number of p o s s i b l e i n t e r a c t i o n s i n a system and the degree t o which they are s t r u c t u r e d  (Johnson and Raven 1 9 7 0 ) , d i v e r s i t y  s h o u l d i n c r e a s e as the number o f s p e c i e s i n c r e a s e s and as  the  d i s t r i b u t i o n o f i n d i v i d u a l s i n t o s p e c i e s becomes more even. The concept o f d i v e r s i t y has proven most u s e f u l i n i n t e r p r e t a t i o n s of l a r g e - s c a l e p o p u l a t i o n a l patterns i n nature. For example, s p e c i e s d i v e r s i t y o f b o t h f l o r a s and faunas  has  152 repeatedly  been observed t o i n c r e a s e  i n a gradient  c l i m a t e s toward the warm t r o p i c s and from h i g h  from c o l d  elevations  downward ( F i s c h e r 1960; MacArthur 1965; P i a n k a 1966; Baker 1970). Rough p o s i t i v e c o r r e l a t i o n s have been made between the a r e a o f i s l a n d s and the d i v e r s i t y o f t h e i r b i o t a (MacArthur and W i l s o n 1967; Johnson et al. 1968; Johnson and Raven 1970, 1973; Simberloff  1970). P a t t e r n s o f d i v e r s i t y have been s t u d i e d i n  r e l a t i o n to w i t h i n - and b e t w e e n - h a b i t a t e n v i r o n m e n t a l h e t e r o geneity adjuncts  (Johnson et al. 1968; W h i t t a k e r 1970a, 1972) and as to vegetation c l a s s i f i c a t i o n s w i t h i n  certain  g e o g r a p h i c a l areas ( W h i t t a k e r 1965; Monk 1967; A u c l a i r and Goff 1971; d e l M o r a l 1973). More s p e c i a l i z e d  investigations  have r e v e a l e d b o t h d i r e c t . ( e d n n e l l and O r i a s 1964; MacArthur 1969; S i n g h and M i s r a 1969) and i n v e r s e  (McNaughton 1968;  M a r g a l e f 1969; W h i t t a k e r 1972) c o r r e l a t i o n s between d i v e r s i t y and p r o d u c t i v i t y . I n p l a n t c o m m u n i t i e s , attempts t o consistent  produce  c o r r e l a t i o n s between d i v e r s i t y and a number o f  environmental factors  such as m o i s t u r e  Goff 1971; W h i t t a k e r 1 9 7 2 ) , a l t i t u d e  (Monk 1967; A u c l a i r and  ( W h i t t a k e r and N i e r i n g  1965; Daubenmire 1 9 7 0 ) , s o i l f e r t i l i t y and pH (Loucks 1962; Monk 1 9 6 7 ) , have not been s u c c e s s f u l .  Diversity is  generally  reduced by a i r p o l l u t i o n (Gordon and Gorham 1963; G i l b e r t 1965; Skye 1968; Nash 1 9 7 2 ) , gamma i r r a d i a t i o n (Woodwell 1967; Woodwell and W h i t t a k e r 1 9 6 8 ) , and o v e r g r a z i n g ( W h i t t a k e r but Harper (19 69) has demonstrated g r a z i n g may a c t u a l l y i n c r e a s e  1972),  t h a t l i g h t or moderate  diversity.  D i v e r s i t y o f t e n i n c r e a s e s w i t h s u c c e s s i o n ( M a r g a l e f 1963; Monk 1967; Odum 1969; R e i n e r s et al. 1 9 7 1 ) , but i n some cases  153 d e c r e a s e s from l a t e s u c c e s s i o n a l s t a g e s t o the c l i m a x (Loucks 1970; A u c l a i r and Goff 1 9 7 1 ) . R e i n e r s et al. (1971)  followed  changes i n d i v e r s i t y d u r i n g s u c c e s s i o n on g l a c i a l moraines o f known age i n G l a c i e r B a y , A l a s k a . They found t h a t an  initial  r a p i d i n c r e a s e i n d i v e r s i t y d u r i n g the f i r s t 10 0 y e a r s was f o l l o w e d by a more g r a d u a l i n c r e a s e t o a maximum i n the muskeg steady  s t a t e ( c l i m a x ) a t 200 y e a r s p l u s (up to 1500 y e a r s ? ) .  S u c c e s s i o n at G l a c i e r Bay proceeds  from bare ground to  t h i c k e t s to a l d e r and cottonwood f o r e s t s hemlock f o r e s t s  shrub  t o S i t k a spruce and  and e v e n t u a l l y v i a p a l u d i f i c a t i o n to muskeg.  Inasmuch as I i m p l i c a t e d p a l u d i f i c a t i o n o f c o a s t a l f o r e s t  in  t h e f o r m a t i o n o f the T o f i n o a r e a sphagnum b o g s , one would expect t h a t Wade's Bog, t h e most s u c c e s s i o n a l l y advanced, would have a h i g h e r d i v e r s i t y t h a n Ogg's Bog. However, such i s not the case (Table 1 8 ) . There i s l i t t l e agreement as t o the causes o f and g r a d i e n t s  differences  i n s p e c i e s d i v e r s i t y . Attempts have been made t o  e x p l a i n p a t t e r n s o f d i v e r s i t y i n terms o f time a v a i l a b l e f o r e v o l u t i o n (Sanders  1969; Baker 1 9 7 0 ) , s p a t i a l h e t e r o g e n e i t y  the p h y s i c a l environment  of  (Ashton 1969; MacArthur 1969; R i c h a r d s  1969; W h i t t a k e r 1 9 7 2 ) , i n t e r s p e c i f i c c o m p e t i t i o n (Dobzhansky 1950; M i l l e r 1969; W h i t t a k e r 1969) i n c l u d i n g a l l e l o p a t h y '.(Whittaker 1970b; W h i t t a k e r and Feeny 1 9 7 1 ) , p r e d a t i o n p r e s s u r e (Paine 1966; S p i g h t 1967; Harper 1969; Janzen 1 9 7 0 ) , parasite  interactions  host-  (Barbehenn 1 9 6 9 ) , c l i m a t i c s t a b i l i t y o r  e n v i r o n m e n t a l p r e d i c t a b i l i t y (Sanders  19 68; S l o b o d k i n and  Sanders 1969), p r o d u c t i v i t y ( C o n n e l l and O r i a s 1964; McNaughton 1968; S i n g h and M i s r a 1 9 6 9 ) , r e l a t i v e r a t e s o f  154 of s p e c i a t i o n (Simpson 1964, 1969; S t e h l i et al. 1 9 6 9 ) , and v a r i o u s c o m b i n a t i o n s o f the above (see P i a n k a 1966; Baker 1970; and Johnson and Raven 1970 f o r g e n e r a l  discussions).  T h i s b r i n g s us t o the q u e s t i o n o f the r e l a t i o n s h i p  between  d i v e r s i t y and s t a b i l i t y . As used h e r e , s t a b i l i t y does not  refer  t o the e n v i r o n m e n t a l s t a b i l i t y o f the p r e v i o u s p a r a g r a p h ,  but  i s t o be u n d e r s t o o d r a t h e r as the s t a b i l i t y t h r o u g h time o f a p l a n t community t y p e . More p r e c i s e l y , the s t a b i l i t y o f a community may be d e f i n e d as i t s r e s i s t a n c e a t i o n s and consequent  persistence  to external  i n time (Odum 1969;  perturbPreston  1969). Communities o f g r e a t e r d i v e r s i t y are then s a i d t o be more s t a b l e  ( H u t c h i n s o n 1959; Odum 1969; W h i t t a k e r and  Woodwell 1972; see Woodwell and Smith 1 9 6 9 ) . Given t h i s ,  and  t h e f a c t t h a t each o f the f o u r study communities has a different  s p e c i e s d i v e r s i t y , can I v a l i d l y c l a i m t h a t ,  example, the s a l t marsh i s the l e a s t s u b a l p i n e meadow the most s t a b l e It  stable,  for  and the  o f t h e s e communities?  i s i m p o r t a n t to s p e c i f y the time s c a l e i n v o l v e d . I n  most d i s c u s s i o n s o f d i v e r s i t y and s t a b i l i t y , a l o n g - t e r m ( e v o l u t i o n a r y ) view r a t h e r t h a n a s h o r t - t e r m view i s at l e a s t persistence  implicit.  (successional)  Thus, we are d e a l i n g w i t h the  o f a community type i n e v o l u t i o n a r y t i m e ;  s u c c e s s i o n a l t r e n d s are s u b l i m a t e d (McCullough 1970). When one speaks o f the s t a b i l i t y o f a community, one must i n c l u d e the s u c c e s s i o n a l phases o f t h a t community. F o r example, evolutionary future  the  o f the s a l t marsh community type i n v o l v e s  b o t h the p i o n e e r mud f l a t  stages and the advanced h i g h marsh,  as w e l l as the d e g e n e r a t i v e ,  eroded stages o f the marsh  (cf.  155 Redfield  1 9 7 2 ) ; h e a t h e r meadows i n England ( B a r c l a y - E s t r u p  1970, 1971; B a r c l a y - E s t r u p and Gimingham 1969) and sugar maple forests  i n W i s c o n s i n (Loucks 1970) e v o l v e as systems o f s e r e s  c y c l e d by p e r i o d i c , random p e r t u r b a t i o n s The e v o l u t i o n a r y consequence  ( c f . Watt 1947).  o f the proposed  direct  r e l a t i o n s h i p between d i v e r s i t y and s t a b i l i t y s h o u l d be a p o t e n t i a l l y self-augmenting  increase  i n d i v e r s i t y (Hutchinson  1959; W h i t t a k e r 1969; W h i t t a k e r and Woodwell 1 9 7 2 ) ; i . e . , i f d i v e r s i t y increases  s t a b i l i t y , t h e r e s h o u l d be s e l e c t i o n  i n c r e a s e d d i v e r s i t y , which i n t u r n c o n f e r s etc.  Such a s e l e c t i v e mechanism r e q u i r e s  greater  t h a t the  for  stability, plant  community i t s e l f be a u n i t o f e v o l u t i o n ( W h i t t a k e r and Woodwell 1972). T h i s i s t h e o r e t i c a l l y f e a s i b l e , as t o be a s e l e c t i v e u n i t ' an e n t i t y need o n l y have v a r i a t i o n , and h e r i t a b i l i t y ( L e w o n t i n 1970). Genes, c e l l s ,  organs,  o r g a n i s m s , p o p u l a t i o n s , s p e c i e s , c o m m u n i t i e s , and fulfill  these requirements  reproduction,  ecosystems  and thus a l l can e v o l v e ( L e w o n t i n  1970). H e r i t a b i l i t y w i l l be g r e a t e r , and the r a t e of e v o l u t i o n faster,  i n those e n t i t i e s  w i t h the t i g h t e s t  internal organi-  z a t i o n ( L e w o n t i n 1970; S t e b b i n s and Lewontin 1972). The closeness  o f the o r g a n i z a t i o n d e c r e a s e s c o n t i n u o u s l y i n the  progression:  gene, c e l l ,  organ, organism, p o p u l a t i o n ,  community, ecosystem (Baker 1966a); o r " . . . c h a n c e  species,  plays a  g r e a t e r r o l e a t the ecosystem end o f the p r o g r e s s i o n " and B u e l l  1969).  A p l a n t community may be viewed as a more or integrated  (Langford  assemblage  of species  less  r e s u l t i n g from " n a t u r a l  s e l e c t i o n o p e r a t i n g between groups o f organisms and  adjusting  t h e i r mutual s t r a t e g i e s t o p e r m i t i n c r e a s i n g d i v e r s i t y and more e f f i c i e n t e n v i r o n m e n t a l e x p l o i t a t i o n . . . " (Harper 19 6 9 ) . Thus, a community has c h a r a c t e r i s t i c s homeostasis,  maturity,  and energy f l u x t h a t c o r r e s p o n d to those o f  other b i o l o g i c a l e n t i t i e s . plant  such as g r o w t h ,  R e l a t i o n s h i p s such as  herbivore-  ( E h r l i c h and Raven 1964; B r e e d l o v e and E h r l i c h 1968;  Janzen 1969, 1970; B e a t t i e , B r e e d l o v e , and E h r l i c h  1973),  parasite-host  ( P e r s o n 1959; Chabora and P i m e n t e l 1 9 7 0 ) ,  predator-prey  ( H o l l i n g 196 5 ) , and p o l l i n a t o r - p l a n t  ( F a e g r i and van der P i j l  1 9 7 1 ) , symbioses  (Janzen 1966; Henry 19  1967; S c o t t 1 9 6 9 ) , and p o s s i b l e synergisms Baker 1971; P o j a r 1973b) w i l l by g e n e t i c  interactions  ( B a k e r , Cruden, and  feedback  and  p o p u l a t i o n r e g u l a t i o n i n c r e a s e the c o m p l e x i t y and o f the e c o s y s t e m , i n c r e a s i n g i t s homeostasis  integration  and presumably  i t s s t a b i l i t y (Brock 1967; P i m e n t e l 1968; c f . H a i r s t o n et al. 1960 ; Murdoch 1966 ;•* S l o b o d k i n et al. 1967 , and E h r l i c h and B i r c h 1967). Note t h a t t h i s does not r e q u i r e an o r g a n i s m i c  (Clements  19 36) concept o f the p l a n t community, nor does i t  strictly  conform t o the n o t i o n of a community as merely a  fortuitous  assemblage  of i n d i v i d u a l species  t h i s approach a p p r o p r i a t e s  (Gleason 1926, 1939).  Rather,  elements o f b o t h t r a d i t i o n a l l y  opposed ( c f . W h i t t a k e r 1962, 19 67; Daubenmire 19 66; M c i n t o s h 1967b, 1970, 1972; Langford and B u e l l 1969) s c h o o l s of s y n e c o l o g y . S p e c i e s do e v o l v e toward n i c h e and h a b i t a t  differ-  e n t i a t i o n , r e d u c t i o n o f c o m p e t i t i o n , and i n d i v i d u a l i t y o f d i s t r i b u t i o n ( W h i t t a k e r 1967, 1969, inter superimposed on the s p e c i e s  alia).  However,  e v o l u t i o n i s the h i g h e r  order  157 (Odum  e v o l u t i o n o f the community toward i n c r e a s e d homeostasis  1969). I n t e r s p e c i f i c c o m p e t i t i o n c o n t i n u a l l y a p p l i e s a d i v i s i v e force to aggregations  of s p e c i e s ; t h i s i s countered by the  c o h e s i v e o r c e n t r i p e t a l f o r c e of s e l e c t i o n f o r community homeostasis  and s t a b i l i t y .  Now, a l l t h i s begs the q u e s t i o n , Does i n c r e a s e d increase  really  diversity  s t a b i l i t y ? I can accept the argument t h a t  g r e a t e r d i v e r s i t y w i l l i n c r e a s e community s t a b i l i t y i n the face of a b i o l o g i c a l p e r t u r b a t i o n .  For example, a monoculture  (say a Midwestern c o r n f i e l d ) would be most s u s c e p t i b l e t o an outbreak o f a v i r u l e n t pathogen or p a r a s i t e o r an h e r b i v o r e e p i d e m i c . F u r t h e r m o r e , the more d i v e r s e a community i s , b e t t e r i t s h o u l d accommodate l e s s c a t a s t r o p h i c , occurrences  such as death and replacement  windthrow, disturbance  the  commonplace  of i n d i v i d u a l s ,  by g r a z i n g or b u r r o w i n g a n i m a l s , and  e n t r y of new t a x a . On the o t h e r hand, I t h i n k t h a t p h y s i c a l f a c t o r s  that  c o u l d d i s r u p t a community ( f i r e , g l a c i a t i o n , d r o u g h t ,  rise  fall etc.)  of the water t a b l e ,  clear-cutting, pollution, bulldozers,  would a c t more i n d i s c r i m i n a t e l y , r e g a r d l e s s  o f community  d i v e r s i t i e s . P l a n t communities have been shown t o be to the e f f e c t s  sensitive  o f i o n i z i n g r a d i a t i o n (Woodwell 1967, 1970;  Woodwell and W h i t t a k e r 1 9 6 8 ) , p e s t i c i d e s et  and  al. 1 9 7 2 ) , and e u t r o p h i c a t i o n  ( C a n t l o n 1969; Mosser  (Hurd et al. 1 9 7 1 ) , as  well  as t o more heavy-handed t r e a t m e n t s such as c l e a r - c u t t i n g and h e r b i c i d e a p p l i c a t i o n (Bormann et al. 1968; L i k e n s et al. 1970). The mechanisms of r e c o v e r y from such d i s t u r b a n c e s begun t o be s t u d i e d  have o n l y  ( L i k e n s et al. 1969; L i k e n s and Bormann 1972  158 Marks and Bormann 19 7 2 ) . The s t u d i e s have been done e i t h e r w i t h o u t the r e l a t i o n s h i p  between d i v e r s i t y and s t a b i l i t y  m i n d , or t h e y are too e q u i v o c a l ( c f .  Rosenzweig 19 71 and  M c A l l i s t e r et al. 1972) f o r g e n e r a l i z a t i o n . offered  Most o t h e r d a t a  as e v i d e n c e are l a r g e l y p h y t o g e o g r a p h i c a l  necessarily  anecdotal  in  and  (see MacArthur and W i l s o n 1967;  Simberloff  19 70; MacArthur 19 72; Diamond 19 7 3 ) . A r e c e n t  experiment  (Hurd et al. 1971) more d i r e c t l y apropos  the  problem i n d i c a t e d t h a t , at l e a s t a t the l e v e l o f p r i m a r y producers ( p l a n t s ) ,  s t a b i l i t y was p o s i t i v e l y c o r r e l a t e d  d i v e r s i t y . However, t h e s e r e s u l t s have been q u e s t i o n e d  with (cf.  Harger et al. 1972; H o l t et al. 1 9 7 2 ) , and a n o t - a l t o g e t h e r comparable  experiment  by H a i r s t o n et al. (19 68)  t h a t " . . . m u c h more e x p e r i m e n t a l  concluded  and o b s e r v a t i o n a l work i s  n e c e s s a r y before the n a t u r e o f any f u n c t i o n a l  relationship  between d i v e r s i t y and s t a b i l i t y can be c l a i m e d w i t h I  agree.  confidence"  159 J.  Index o f p o t e n t i a l r e c o m b i n a t i o n .  The v a r i e t y of p l a n t g e n e t i c systems i n n a t u r e t h e i r s u s c e p t i b i l i t y to hereditable  reflects  v a r i a t i o n , adaptation,  n a t u r a l s e l e c t i o n ( D a r l i n g t o n 19 39; Grant 1958). That  and  the  d i v e r s i t y o f t h e s e systems i s not random suggests t h a t c o r r e l a t i o n s e x i s t between c e r t a i n k i n d s o f r e p r o d u c t i v e s t r a t e g i e s and p a r t i c u l a r k i n d s o f g e n e t i c systems. nonrandom v a r i a t i o n m a n i f e s t s  itself  The  i n a number o f r e p r o d u c t i v e  methods t h a t embody a c h a r a c t e r i s t i c c o m b i n a t i o n o r syndrome of p o s i t i v e l y correlated characters,  morphological, physio-  l o g i c a l , c y t o l o g i c a l , and e c o l o g i c a l (Ornduff 1969). For i n s t a n c e , herbaceous  s p e c i e s t h a t are w i n d - p o l l i n a t e d and  w i n d - d i s p e r s e d t e n d to have: r e d u c e d , i n c o n s p i c u o u s f l o w e r s , o f t e n u n i s e x u a l o r , - ' i f h e r m a p h r o d i t i c , s t r o n g l y dichogamous ; f l o w e r s aggregated  i n t i g h t , many-flowered  inflorescences;  a n t h e r s e x s e r t e d and w i t h c o p i o u s , d r y , l i g h t ' p o l l e n ; e x s e r t e d stigmas w i t h a l a r g e s u r f a c e  area;  s m a l l , numerous  propagules  o f t e n b e s e t w i t h w i n g e d , h a i r l i k e , o r plumose appendages; and l a r g e , clumped p o p u l a t i o n s o c c u p y i n g open h a b i t a t s Whitehead 1969; F a e g r i and van der P i j l  (Pijl  19 69;  1 9 7 1 ) . As a n o t h e r ,  l e s s i n c l u s i v e example, m o r p h o l o g i c a l dimorphism o f  floral  p a r t s ( i . e . , d i s t y l y ) and d i a l l e l i c s e l f - i n c o m p a t i b i l i t y are two independent  f e a t u r e s o f b r e e d i n g systems g e n e r a l l y found  t o g e t h e r presumably becauise they p r o d u c e , i n c o m b i n a t i o n , an i n c r e a s e d e f f i c i e n c y o f c r o s s - p o l l i n a t i o n and c r o s s fertilization  ( V u i l l e u m i e r 1967).  I t i s p o s s i b l e t o i n v e s t i g a t e the g e n e t i c systems o f  160 plants  i n an e v o l u t i o n a r y c o n t e x t ,  systems  k e e p i n g i n mind t h a t t h e s e  f u n c t i o n p r i m a r i l y i n b a l a n c i n g constancy and v a r i a -  b i l i t y i n reproduction (Stebbins  19 50; Grant 19 5 0 ) . The  efficiency  o f t h i s compromise between immediate f i t n e s s  long-range  flexibility  and  i s b e s t e v a l u a t e d by c o n s i d e r a t i o n o f  the c o n t r o l o f r e c o m b i n a t i o n . R e l a t i v e m u t a t i o n a l r a t e s o f h i g h e r p l a n t s p e c i e s are too p o o r l y known to a s s e s s m u t a t i o n a l c o n t r i b u t i o n s t o g e n e t i c v a r i a b i l i t y , so i t i s n e c e s s a r y this  i n v e s t i g a t i o n t o assume t h a t the c h a r a c t e r i s t i c  r a t e s of s e x u a l l y r e p r o d u c i n g h i g h e r p l a n t s  are  o f the same o r d e r o f magnitude.  p o t e n t i a l performance  of different  and maintenance  mutation  approximately  the same, o r at l e a s t  generation  in  The  r e c o m b i n a t i o n systems  i n the  o f g e n e t i c v a r i a b l i t y can t h e n be  compared. I n the f o l l o w i n g d i s c u s s i o n I have o u t l i n e d a scheme evaluate  the r e c o m b i n a t i o n p o t e n t i a l o f each s p e c i e s  to  i n the  study communities. Many o f the i d e a s are m o d i f i e d from papers by F r y x e l l ( 1 9 5 7 ) , Grant ( 1 9 5 8 ) , Baker ( 1 9 5 9 ) , C a r l q u i s t  (1966),  Mosquin ( 1 9 6 6 ) , and Ornduff ( 1 9 6 9 ) . The approach i n v o l v e s n u m e r i c a l l y s c a l i n g v a r i o u s c y t o l o g i c a l , m o r p h o l o g i c a l , and e c o l o g i c a l components  o f the g e n e t i c system and combining  v a l u e s f o r a l l components  i n a f i n a l Index o f P o t e n t i a l  Recombination ( I . P . R . ) f o r each s p e c i e s . component  (eg.,  Within a given  l e v e l o f p l o i d y ) , t h e r e i s u s u a l l y a number o f  s t a t e s ( e g . , o c t o p l o i d and above, h e x a p l o i d ,  tetraploid,  d i p l o i d ) t h a t have^been.- a r r a n g e d ' in,.order;.6.f' i n c r e a s i n g potential  recombination.  161 1. Length o f  generation.  "The r e c o m b i n a t i o n system r e g u l a t e s the g e n e r a t i o n o f v a r i a b i l i t y by r e s t r i c t i n g the t y p e s o f gametes produced and the t y p e s o f zygotes formed" (Grant 1958). T h i s r e g u l a t i o n imposed d u r i n g each s u c c e s s i v e s e x u a l g e n e r a t i o n . length of different  plant species  The  w i l l be a f u n c t i o n o f the g e n e r a t i o n  things  should r e a l i z e  more r e c o m b i n a t i o n per u n i t time than l o n g - l i v e d A l s o , lengthy l i f e  the  species  length. A l l other  b e i n g e q u a l , annuals o r s h o r t - l i v e d p e r e n n i a l s  and woody p l a n t s .  generation  i s h i g h l y v a r i a b l e , so  amount o f r e c o m b i n a t i o n g e n e r a t e d p e r u n i t time p e r  is  perennials  cycles could r e s u l t  c r o s s i n g between p a r e n t s and o f f s p r i n g and thus  in  increase  i n b r e e d i n g (Mosquin 1966). 1 - woody p l a n t s 2 - l o n g - l i v e d herbaceous  perennials  3 - s h o r t - l i v e d herbaceous 4 -  2.  perennials  annuals  B a s i c chromosome  number.  Independent assortment o f the chromosomes a t m e i o s i s recombine genes borne on s e p a r a t e chromosomes.  The g r e a t e r  number o f chromosomes, the g r e a t e r the p o t e n t i a l  will the  recombination  (Grant 1958, 19 7 1 ; S t e b b i n s 19 7 1 b ) . A l t h o u g h the number o f p o s s i b l e chromosome c o m b i n a t i o n s i n c r e a s e s  exponentially with  h a p l o i d chromosome number, I have chosen t o reduce  the  p o s s i b i l i t i e s t o a much s m a l l e r s c a l e , namely t h a t d e f i n e d by  162 x  ( b a s i c chromosome number)/2. The range o f the s c a l e i n t h i s  s t u d y would be maorooarpa phyllidium  3 (x = 6 f o r  Trigloohin  and P. m a r i t i m a )  to  8.5  and  maritimum  (x = 17 f o r  Plantago  Nephro-  orista-galli).  3.  R e l a t i v e chromosome l e n g t h .  Recombination o f l i n k e d genes i s promoted by a h i g h chiasma f r e q u e n c y .  I l a c k the d a t a t o c a l c u l a t e a r e c o m b i n a t i o n  i n d e x ( S t e b b i n s 1950) f o r each s p e c i e s , but w i l l use r e l a t i v e chromosome l e n g t h (based on camera l u c i d a drawings ( F i g s .  14-  110) o f m i c r o s p o r o c y t e m e i o t i c chromosomes) as an e x p r e s s i o n of  c r o s s o v e r potential::,.--since the. number o f c h i a s m a t a tends  t o i n c r e a s e w i t h chromosome l e n g t h (Swanson 1957; S t e b b i n s 1971b). Q u a l i t a t i v e e s t i m a t e s o f chromosome l e n g t h have been s c a l e d from 1 t o 7. 1 - eg.,  Junous  2 - eg.,  Vaooinium  sitchensis 3 - eg.,  Ledum  maritima, 4 - eg.,  cusickii,  Phlox  3  latifolius.  Epilobium  Linnaea  3  virginica  maritima  Desohampsia 3  Lupinus  3  Spergularia canadensis  Gentiana  3  spp.  Gaultheria shallon, Valeriana  groenlandicum  mollis  viridula 7 - eg.,  Veronica  Plantago  boreale 6 - eg.,  spp.,  Salioornia  Arnica 5 - eg.,  3  spp., C a r e x  3  3  borealis,  Glaux  Castilleja  Sanguisorba  miniata.  officinalis  3  diffusa. 3  Puocinellia  douglasiana  3  pumila  Apargidium  3  Silene parryi.  oespitosa, Gentiana  sceptrum  Claytonia lanceolata, Senecio  Maianthemum  alpinum.  d i l a t a t u m , Elymus  3  Festuoa  triangularis.  glauous.  16 3 4.  Level of p l o i d y .  P o l y p l o i d y i s c o n s i d e r e d t o promote and p r e s e r v e t y p i c uniformity i n populations while retarding  pheno-  species  e v o l u t i o n a r y change ( S t e b b i n s 1950, 1971b; Mosquin 1966; De Wet 1971a). The d i s r u p t i v e e f f e c t s  o f m u t a t i o n , r e c o m b i n a t i o n , and  s e l e c t i o n t e n d t o be b u f f e r e d by p o l y s o m i c i n h e r i t a n c e 1962; S t e b b i n s 1971b). Presumably the b u f f e r i n g  (Dawson  effect  increases with higher ploidy l e v e l s . Polyhaploidy (functional h a p l o i d y r e s u l t i n g from a r e v e r s a l o f p o l y p l o i d y ) i s possible i n flowering plants  quite  ( c f . Raven and Thompson 1964;  Jones 1970; Ornduff 1970a; S t e b b i n s 1970b; De Wet 1971b; Anderson 1 9 7 2 ) , but i s not r e a l l y i m p o r t a n t i n t h i s  analysis,  s i n c e the p l o i d y s t a t u s quo i s under c o n s i d e r a t i o n , not  its  mode o f o r i g i n . 1 - o c t o p l o i d and up 2 - hexaploid 3 - tetraploid 5 -  diploid  The b r e e d i n g system o f f l o w e r i n g p l a n t s , t h r o u g h a v a r i e t y o f m o r p h o l o g i c a l and p h y s i o l o g i c a l mechanisms, c o n t r o l s  the  amount o f o u t c r o s s i n g i n s p e c i e s p o p u l a t i o n s and c o n s e q u e n t l y e x e r c i s e s a p o w e r f u l c o n t r o l <over the amount o f  genetic  v a r i a b i l i t y p r e s e n t i n a p o p u l a t i o n . The most obvious o f these mechanisms w i l l be d i s c u s s e d under headings  5-12.  164 5. S e p a r a t i o n o f s e x u a l f u n c t i o n s  i n time.  Dichogamy i s the asynchronous m a t u r a t i o n o f s t i g m a and anther. I t includes both protandry  (pollen available  before  stigma i s mature) and protogyny ( s t i g m a r e c e p t i v e b e f o r e p o l l e n i s shed).  the  Homogamy i s the o p p o s i t e c o n d i t i o n , w i t h  both sexual functions  o c c u r r i n g at the same t i m e . The g r e a t e r  the degree o f dichogamy, the h i g h e r the p r o b a b i l i t y o f  out-  c r o s s i n g (Mosquin 1966; K u g l e r 1970; F a e g r i and van der  Pijl  1971). 1 - homogamy 2 - moderate dichogamy 4 - s t r o n g dichogamy ( i n c l u d e s d i o e c y )  6. S e p a r a t i o n o f s e x u a l f u n c t i o n s  Herkogamy ( F a e g r i and van der P i j l separation is  in  space.  19 71) i s the  spatial  o f a n t h e r s and s t i g m a w i t h i n the same f l o w e r . Monoecy  the c o n d i t i o n o f s e p a r a t i o n  o f the sexes i n  different  f l o w e r s o f the same p l a n t ; d i o e c y i s the s e p a r a t i o n  of  sexes on d i f f e r e n t  the  plants.  D i o e c y may be c o n s i d e r e d  ultimate i n morphological adaptation  for outcrossing.  the  Clearly,  o u t c r o s s i n g and p o p u l a t i o n v a r i a b i l i t y w i l l be promoted by progressive  s p e c i a l i z a t i o n toward d i o e c y (Grant 1958; Baker  1959; Mosquin 1966; C a r l q u i s t 1966). 1 - hermaphrodite, rotundifolia,  s e x u a l organs adjacent Spergularia  2 - herkogamic hermaphrodite  (eg.,  Drosera  canadensis')  ( e g . , Kalmia  polifolia,  165 Plantago  macrooarpa)  3 - monoecy ( e g . ,  Carex  obnupta,  Carex  4 - p a r t i a l dioecy ( e g . , . T h a l i o t r u m 5 - strict  (?-).-:dioecy  (eg.,  Myrioa  pluriflora)  oooidentale) gale,  Antennaria  Many s p e c i e s o f Compositae have u n i s e x u a l f l o w e r s p i s t i l l a t e r a y f l o r e t s ) mixed w i t h a m a j o r i t y o f f l o w e r s i n the head. as i n t e r m e d i a t e  lanata)  (usually  hermaphrodite  Such a s t e r a c e o u s s p e c i e s w i l l be c l a s s e d  between c a t e g o r i e s  1 and 2 above.  7. H e t e r o s t y l y .  S p e c i e s h a v i n g f l o w e r s w i t h two or more d i s t i n c t s t y l e length ratios i n different  p l a n t s are termed  stamen:  heterostylous.  I n d i v i d u a l s h a v i n g f l o w e r s w i t h l o n g s t y l e s and s h o r t  stamens  may e x i s t i n the same p o p u l a t i o n as those h a v i n g f l o w e r s w i t h s h o r t s t y l e s and l o n g stamens (Darwin 1877; Whitehouse 1959; K u g l e r 1970; F a e g r i and van d e r P i j l accompanies i n c o m p a t i b i l i t y systems  1971). H e t e r o s t y l y o f t e n (Pandey 19 60) such t h a t  i n t r a m o r p h s e l f - s t e r i l i t y e x i s t s ; e g . , between a s h o r t  style  and l o n g a n t h e r s (from a s h o r t - s t y l e d f l o w e r ) . Seed s e t  thus  g e n e r a l l y o c c u r s as a r e s u l t o f " l e g i t i m a t e " p o l l i n a t i o n when two d i f f e r e n t  f l o r a l morphs are c r o s s e d . As a h i g h l y s p e c i a l i z e d  form of o u t c r o s s i n g (Crowe 1964; V u i l l e u m i e r 1 9 6 7 ) ,  heterostyly  would be expected t o i n c r e a s e v a r i a b i l i t y w i t h i n a s p e c i e s p o p u l a t i o n (Mosquin 1966; Ornduff  19 6 9 ) . N e v e r t h e l e s s , I a s s i g n  a r e l a t i v e l y low v a l u e t o h e t e r o s t y l y i n accordance observations  (Mulcahy and C a p p o r e l l o 1970; Ornduff  with 1970b & c)  t h a t h e t e r o s t y l y per se i s o n l y m o d e r a t e l y e f f i c i e n t i n  166 reducing i l l e g i t i m a t e p o l l i n a t i o n . 1 - homostyly 3 - heterostyly  (the o n l y example i n t h i s study  Nephrophyllidium  is  orista-galli)  8. S e x u a l r e p r o d u c t i o n .  R e p r o d u c t i o n i n h i g h e r p l a n t s u s u a l l y has two s e x u a l and n o n s e x u a l . in  components:  S e x u a l and n o n s e x u a l methods are combined  a v a r i e t y o f ways by p l a n t s p e c i e s ,  and t h e r e appears t o be  an i n v e r s e c o r r e l a t i o n between opposing methods ( S a l i s b u r y 1942). O b l i g a t e apomixis sensu agamospermy)  lato  (both v e g e t a t i v e r e p r o d u c t i o n and  i s rare (Gustafsson 1946-47). Intermediacy  obligate sexual reproduction  (as i n many annuals)  between  and o b l i g a t e  apomixis i s by f a r the commonest c o n d i t i o n i n f l o w e r i n g p l a n t s (Grant 1971). T h i s i n t e r m e d i a c y may be viewed as a mixed s t r a t e g y combining the promotion o f r e c o m b i n a t i o n v i a s e x u a l r e p r o d u c t i o n w i t h the p e r p e t u a t i o n  and r a p i d p r o p a g a t i o n o f  f a v o r a b l e gene c o m b i n a t i o n s v i a n o n s e x u a l  reproduction  ( S a l i s b u r y 1942; S t e b b i n s 1950, 1957a, 1958; G a d g i l and S o l b r i g 1972 ) . The g r e a t e r the degree o f a p o m i x i s , the l e s s the  genetic  r e c o m b i n a t i o n w i t h i n the pure l i n e . As a c o r o l l a r y , one would expect a p o s i t i v e c o r r e l a t i o n between the degree o f s e x u a l r e p r o d u c t i o n and the e x t e n t o f s p e c i a t i o n w i t h i n t a x a  (Stebbins  1957a; Baker 1959; Ornduff 1969). Such a c o r r e l a t i o n has demonstrated  by W e l l s (1969) i n c o n t r a s t i n g the  been  speciation  w i t h i n crown-sprouting vs. o b l i g a t e l y - s e e d i n g sections of  167 and Ceanothus  Arctostaphylos  i n the C a l i f o r n i a  c h a p a r r a l . As  an a s i d e , i t s h o u l d be noted t h a t h e t e r o z y g o s i t y as a r e s u l t of  s p o r a d i c o u t c r o s s i n g w i l l be p r e s e r v e d by apomixis i n  contrast  t o autogamy, w h i c h w i l l g r a d u a l l y  homozygosity a f t e r  a burst  of segregations  1967; F a e g r i and van der P i j l  re-establish (Grant 1958; R o l l i n s  1971).  1 - o b l i g a t e a p o m i x i s (the o n l y p o s s i b l e c a n d i d a t e is  here  Poa cusickii)  5 - w h o l l y s e x u a l r e p r o d u c t i o n ( e g . , Microsteris Spergularia  gracilis,  canadensis)  9. Mode o f p o l l i n a t i o n .  The amount o f r e c o m b i n a t i o n r e a l i z e d per g e n e r a t i o n  is  a l s o a f u n c t i o n o f the amount of gene d i s p e r s a l v i a both p o l l i n a t i o n and d i a s p o r e d i s p e r s a l mechanisms.  Population  s t r u c t u r e s b e i n g e q u a l , r e c o m b i n a t i o n due t o p o l l e n d i s p e r s a l s h o u l d be p r o p o r t i o n a l t o the randomness o f b e h a v i o r and distance  o f p o l l e n t r a n s p o r t by the p o l l i n a t i o n v e c t o r .  Clearly,  a u t o m a t i c s e l f - p o l l i n a t i o n o r c l e i s t o g a m y r e p r e s e n t the of  extreme  l e a s t p o t e n t i a l r e c o m b i n a t i o n v i a p o l l i n a t i o n . A t the  extreme, wind p o l l i n a t i o n or anemophily combines the  other  best  chances f o r l o n g i x d i s t a n e e p p o l l e n " t r a n s p o r t v w i t h t h e l e a s t  non-  randomness (Whitehead 1 9 6 9 ) , a l t h o u g h v i c i n i s m i n wind p o l l i n a t i o n i s marked ( C o l w e l l 1951; Whitehead 1969). c r o s s - p o l l i n a t i o n l i e s somewhere between t h e s e two the p o t e n t i a l f o r l o n g d i s t a n c e  gamete d i s p e r s a l i s  tempered by nonrandom p o l l i n a t o r b e h a v i o r due t o  Biotic  extremes: often  strong  168 f l o w e r c o n s t a n c y , as i n bees (Free 19 7 0b; F a e g r i and van der Pijl  1971). My r a n k i n g o f b i o t i c p o l l i n a t i o n v e c t o r s  somewhat a r b i t r a r y . Of t h e s e v e c t o r s , hummingbirds  is (see  S c h l i s i n g and T u r p i n 19 71) and hawkmoths (Janzen 19 71b) p r o b a b l y have the b e s t chances f o r l o n g d i s t a n c e  pollen  d i s p e r s a l , but hummingbirds seem t o be more random, constant  less  i n t h e i r p o l l i n a t i n g a c t i v i t i e s (Grant and Grant 1968;  p e r s o n a l o b s e r v a t i o n s ) . Bumble ..bees , b u t t e r f l i e s s m a l l bees ( m e g a c h i l i d , h a l i c t i d ) , and s m a l l muscid f l i e s  s y r p h i d and c a r r i o n  seem (from the l i t e r a t u r e  observations) to decrease,  and s k i p p e r s , flies,  and my own  i n that order, i n p o t e n t i a l for  l o n g d i s t a n c e p o l l i n a t i o n , w h i l e f l o w e r constancy and nonrandom p o l l i n a t i n g b e h a v i o r seem t o decrease from bees t o to f l i e s ,  i n g e n e r a l ( c f . , inter  alia,  butterflies  Grant 1950; Free 1966,  1970a S b ; L e v i n and K e r s t e r 1967, 1968, 1969a £ b , 1970, 1971; L e v i n 1969, 1970a; Stephen, B o h a r t , and T o r c h i o 1969; F a e g r i and van der P i j l  1971; P r o c t o r and Yeo 1973). Geitonogamy (see  component 12) a l s o i n c r e a s e s nonrandom m a t i n g .  Fertilization  v i a one mode o f p o l l i n a t i o n does not p r e c l u d e u t i l i z a t i o n o f another.  Hagerup (19 50, 19 57) has demonstrated both entomo-  p h i l y and anemophily i n Calluna  and Arbutus,  and P o j a r  has shown t h a t some t y p i c a l l y anemophilous s a l t marsh  (1973b) species  are a l s o p o l l i n a t e d by bumble b e e s . M o r e o v e r , many entomop h i l o u s f l o w e r s are s e r v i c e d ' b y a f a i r l y wide v a r i e t y o f ( C r o s s w h i t e and C r o s s w h i t e 1966; M a c i o r 1 9 7 1 ) , i n c o n t r a s t the extreme c o a d a p t a t i o n s  t h a t c a p t u r e the h e a d l i n e s o f  p o l l i n a t i o n ecology l i t e r a t u r e .  insects to  169 1 - a u t o m a t i c s e l f - p o l l i n a t i o n ( e g . , Drosera Spergularia  votundifolia,  canadensis)  2 - f a c u l t a t i v e s e l f - p o l l i n a t i o n ( e g . , Glaux Sibbaldia  maritima,  procumbens)  3 - e n t o m o p h i l y , p r i m a r i l y by s m a l l muscids Potentilla  flabellifolia)  4- - e n t o m o p h i l y , by s y r p h i d s , b u t t e r f l i e s , (eg.,  Veronica  Penstemon  (eg.,  cusickii,  Agoseris  o r s m a l l bees  aurantiaca,  , respectively)  procerus  5 - p o l l i n a t i o n p r i m a r i l y by bumble bees or hawk: moths (eg.,  Delphinium  nutallianum  or S i l e n e  parryi)  6 - o r n i t h o p h i l y by hummingbirds (Castillej'a  miniata)  a c o m b i n a t i o n o f anemophily and e n t o m o p h i l y  or  (Plantago  maritima) 7 - anemophily ( e g . ,  10.  Trigloohin  Cleistogamy v s .  maritimum)  chasmogamy.  C l e i s t o g a m i c f l o w e r s r e p r e s e n t the u l t i m a t e i n  self-  p o l l i n a t i o n and s e l f - f e r t i l i z a t i o n , s i n c e the f l o w e r s s e l f  and  set  seed w i t h o u t undergoing a n t h e s i s (Uphof 19 38; F a e g r i and  van  der P i j l  1 9 7 1 ) . Ornduff (1969) has d e s c r i b e d the  between showiness of f l o r a l  c h a r a c t e r s and i n c i d e n c e o f c r o s s -  p o l l i n a t i o n , and between f l o r a l pollination.  correlations  i n c o n s p i c u o u s n e s s and  Some s p e c i e s have i n d i v i d u a l s w i t h  self-  either  chasmogamous or c l e i s t o g a m o u s f l o w e r s , as i n  Lithospermum  caroliniense  ( L e v i n 1972d); S p e r g u l a r i a  and  Drosera  rotundifolia  o f t e n b e a r chasmogamous and c l e i s t o g a m o u s  flowers  canadensis  170 on  the same p l a n t . 1 - cleistogamy . 2 - p a r t i a l c l e i s t o g a m y ( e g . , Drosera Pucoinellia  rotundifolia,  pumila)  3 - i n c o n s p i c u o u s chasmogamous f l o w e r s ( e g . , humifusa)  or  inflorescences  4 - conspicuous f l o w e r s o r  11.  (eg.,  Stellaria  Hieracium  gracile)  inflorescences  Compatibility.  I n c o m p a t i b i l i t y mechanisms, though seldom complete and o f t e n s u s c e p t i b l e t o temporary breakdown (Lewis 19 54; Grant 1958;  Crowe 1964; Baker 1966b), s t r o n g l y f a v o r o u t c r o s s i n g  ( E a s t 1940; Bateman 1952; F r y x e l l 1957; Mosquin 1966). 1 - fully  self-compatible  (eg.,  Glaux  maritima,  Soirpus  cernuus)  3 - m o d e r a t e l y s e l f - c o m p a t i b l e ( e g . , Kalmia  polifolia)  5 - m o d e r a t e l y s e l f - i n c o m p a t i b l e ( e g . , Potentilla  pacifica)  7- - p r e d o m i n a n t l y s e l f - incompatible-,--(-eg. , Festuca Erigeron  12.  rubra,  peregrinus)  Chances o f geitonogamy.  P o l l i n a t i o n between two f l o w e r s on the same p l a n t  is  c a l l e d geitonogamy. G e n e t i c a l l y , geitonogamy i s e q u i v a l e n t  to  autogamy, o r p o l l i n a t i o n w i t h i n one f l o w e r ( F a e g r i and van der Pijl  1971). Geitonogamy i s p o s s i b l e o n l y i f the s p e c i e s  more than one f l o w e r p e r p l a n t , and i f i t i s  has  self-compatible.  171 Chances o f geitonogamy w i l l be h e i g h t e n e d i f the p l a n t bears numerous, c l o s e l y s p a c e d , more o r l e s s s i m u l t a n e o u s l y blooming f l o w e r s i n the i n f l o r e s c e n c e , s i n c e p o l l i n a t o r s , e s p e c i a l l y Hymenoptera, t e n d t o v i s i t many f l o w e r s o f the same p l a n t b e f o r e moving on t o the next p l a n t (Free 197Oa; :.Levin 1970a). 1 - chances o f geitonogamy h i g h ( e g . , Valeriana 3 - chances o f geitonogamy n i l ( e g . , Anemone Trientalis  oooidentalis  3  arotioa)  13.  "In  sitohensis)  Dispersibility.  terms o f i t s g e n e t i c r e s u l t s , the d i s p e r s a l o f one  seed i s p o t e n t i a l l y e q u i v a l e n t t o the d i s p e r s a l t o a s i m i l a r d i s t a n c e o f thousands o f p o l l e n g r a i n s " (Grant 1958). Good d i a s p o r e d i s p e r s a l mechanisms can compensate f o r poor p o l l e n dispersal.  Long d i s t a n c e d i s p e r s a l i s e s p e c i a l l y i m p o r t a n t i n  m a i n t a i n i n g v a r i a b i l i t y i n s p e c i e s whose p o p u l a t i o n s are r e l a t i v e l y s m a l l , w i d e l y s p a c e d , and n o t components o f a major, more o r ? ' l e s s c o n t i n u o u s v e g e t a t i o n c o v e r , as i s the case for  mostfofrthe;species  in this  1 - low d i s p e r s i b i l i t y  5 - high d i s p e r s i b i l i t y  14.  study.  (eg.,  Carex  ( e g . , Kalmia  P o p u l a t i o n s i z e and  obnupta)  polifolia)  structure.  Simply as a matter o f p r o b a b i l i t y , l a r g e p o p u l a t i o n s w i l l have more g e n e t i c v a r i a b i l i t y than s m a l l p o p u l a t i o n s . An e x t e n s i v e , c o n t i n u o u s p o p u l a t i o n w i l l p r o b a b l y have more  172 b i o t y p e s and more o u t c r o s s i n g between t h e s e b i o t y p e s t h a n a s m a l l , l o c a l p o p u l a t i o n , g i v e n comparable b r e e d i n g systems. The  D / d v a l u e s t h a t have been c a l c u l a t e d f o r each s p e c i e s  ( S e c t i o n I I I - A ) are u s e f u l here t o e s t i m a t e the p o p u l a t i o n s t r u c t u r e w i t h i n the c o m m u n i t i e s , s i n c e the l a r g e r the v a l u e of D / d , the more clumped the p o p u l a t i o n s t r u c t u r e . 1 - p o p u l a t i o n o f s m a l l s i z e , clumped s t r u c t u r e Elymus  glaucus  3  Lilaeopsis  occidental-is  (eg., Coptis  3  asplenif olia)  2 - s m a l l , r e g u l a r ( e g . , Poa cusickii) clumped ( e g . ,  Thalictrum  3 - moderate, r e g u l a r  (eg.,  o r moderate,  occidentale) Agosevis  aurantiaca,  Phleum  alpinum)  4 - l a r g e , clumped ( e g . , Valeriana 5 - large, regular  (eg.,  Festuca  sitchensis) viridula,  Triglochin  maritimum)  15.  Ecotypic v a r i a t i o n .  Discontinuous, habitat-correlated, hereditable v a r i a t i o n w i l l i n c r e a s e the p o t e n t i a l r e c o m b i n a t i o n and a d a p t i v e v e r s a t i l i t y o f a s p e c i e s i f gene f l o w between the  local  v a r i a n t s o c c u r s o f t e n enough t o m a i n t a i n s p e c i f i c  coherence  but not f r e q u e n t l y enough t o swamp the v a r i a n t s  ( C l a u s e n 19 53;  Clausen and H i e s e y 1 9 5 8 ) . E c o t y p i c v a r i a t i o n depends a g r e a t d e a l on e c o l o g i c a l d i s c o n t i n u i t i e s between ecotypes ; c l i n a l v a r i a t i o n w i l l r e s u l t from ranges r e s t r i c t e d t o a p a r t i c u l a r k i n d of h a b i t a t ,  as i n Plantago  maritima  w i t h i n the s a l t marsh  habitat  (Gregor 1 9 4 6 ) , or from a broad range c o n t i n u o u s  environmental g r a d i e n t s ,  as i n Betula  glandulosa.  It  along  is  p r o b a b l y safe t o p r e d i c t e c o t y p i c v a r i a t i o n i n any w i d e - r a n g i n g s p e c i e s w i t h a wide e c o l o g i c a l a m p l i t u d e , e s p e c i a l l y i f t h a t s p e c i e s o c c u p i e s a range o f d i s c r e t e h a b i t a t s ( c f .  Clausen,  K e c k , and H i e s e y 1941; M c M i l l a n 1959; Mooney and B i l l i n g s 1961; H e s l o p - H a r r i s o n 1964; McNaughton 1966; Bradshaw 1972). 1 - apparently maorooarpa,  no e c o t y p i c v a r i a t i o n ( e g . , Vaooinium  Plantago  sooparium)  3 - moderate e c o t y p i c v a r i a t i o n ( e g . , Junous Erythronium  baltious,  grandiflorum)  5 - marked e c o t y p i c v a r i a t i o n ( e g . , Achillea Desohampsia  16.  oespitosa)  Crossability barriers  An  millefolium,  and e x t e r n a l i s o l a t i n g mechanisms.  i m p o r t a n t b a r r i e r t o gene r e c o m b i n a t i o n i s  interspecifi  h y b r i d s t e r i l i t y , whether g e n i e , chromosomal, m e c h a n i c a l , o r e t h o l o g i c a l (Grant 1963). I n t e r f e r t i l i t y between r e l a t e d can augment the r e c o m b i n a t i o n t h a t t a k e s p l a c e w i t h i n a incompatible, outcrossing species  specie self-  (Anderson and S t e b b i n s 19 54;  S t e b b i n s 19 59, 19 6 9 ) . H y b r i d i z a t i o n can a l s o compensate f o r the l o s s o f r e c o m b i n a t i o n a l p o t e n t i a l due t o predominant fertilization,  as i n Elymus  glaucus  S t e b b i n s 1957b; Grant 1971) o r Hordeum and W i l t o n 1964). I n c o n t r a s t ,  self-  (Snyder 1950, 1951; brachyantherum  Grant (1958, 1971) has  out t h a t i n many i n b r e e d i n g s p e c i e s r e c o m b i n a t i o n i s r e s t r i c t e d by h y b r i d s t e r i l i t y , as i s l i k e l y '  (Mitchell pointed further  174 the case w i t h Spergularia  (see R a t t e r 1965).  canadensis  1 - r e p r o d u c t i v e i s o l a t i o n ( e g . , Silene  -parryi  (Kruckeberg 1955, 1 9 6 1 ) ) . 3 - o c c a s i o n a l h y b r i d i z a t i o n ( e g . , Erigeron  peregrinus  ,  probably) 5 - frequent  The  h y b r i d i z a t i o n ( e g . , Hordeum  an the  rum)  l i m i t s o f the i n d e x ( I . P . R . ) w i t h n = 10 as :a  h y p o t h e t i c a l b a s i c chromosome number a r e :  The  brachy  results  18.5 - 7 8 . 0 .  o f the a n a l y s i s o f r e c o m b i n a t i o n systems  summarized f o r each s p e c i e s i n T a b l e 19. T a b l e 20 l i s t s  are  the  unweighted and w e i g h t e d average I . P . R . ' s f o r each community; the l a t t e r means t a k e i n t o account the importance v a l u e o f each s p e c i e s and thus i n d i c a t e the mean I . P . R . o f the community v e g e t a t i o n , whereas the unweighted mean I . P . R . average o f the community f l o r a . on  i s an  S p e c i e s o f the s a l t marsh h a v e ,  the a v e r a g e , the l o w e s t v a l u e s o f I . P . R . Those o f the two  sphagnum bogs have i n t e r m e d i a t e v a l u e s , and s u b a l p i n e meadow s p e c i e s have the h i g h e s t average I . P . R . However, i n no case  is  the d i f f e r e n c e between any o f t h e means s t a t i s t i c a l l y significant  ( t - t e s t , P >>0.05).  There are some o t h e r i n t e r e s t i n g o b s e r v a t i o n s .  Species  t h a t appear t o be p r e d o m i n a n t l y autogamous have an average I . P . R . o f 4 0 . 3 , compared w i t h an average f o r a l l s p e c i e s o f 47.0.  The i n b r e e d e r s thus have more r e s t r i c t e d r e c o m b i n a t i o n  systems than the o u t b r e e d e r s ,  according to t h i s a n a l y s i s .  Autogamous s p e c i e s , because of t h e i r r e s t r i c t e d r e c o m b i n a t i o n  175 TABLE 19. Index o f P o t e n t i a l R e c o m b i n a t i o n ( I . P . R . ) . feneration l e n g t h . . B a s i c chromosome number/2. R e l a t i v e chromosome l e n g t h . ' ' L e v e l of p l o i d y . Dichogamy. S p a t i a l s e p a r a t i o n of s e x u a l o r g a n s . H e t e r o s t y l y . Sexual r e p r o d u c t i o n . Mode o f p o l l i n a t i o n . Cleistogamy. fompatiblity. Geitonogamy. Dispersibility. ^ P o p u l a t i o n s i z e and s t r u c t u r e . Ecotypic variation. Hybridization. 2  3  5  6  7  8  9  1  1 0  12  1 3  1  1 5  1 6  • a Species 0  -  .•  - - -• •.  •-  Des champ si d~ cesp it os.d Festuca rubra Triglochin- maritimum Salicornia virgih'icd Plantago maritima Juncus balticus Carex lyngbyei Glaux maritima Potentilla pacifica Agrostis exarata Stellaria humifusa Trifolium wormskjoldii Scirpus cernuus P u c c i n e l l i a pumila Spergularia canadensis Distichlis spicata Hordeum brachy antherum Lilaeopsis occidentalis  I  2  3  3.5 3.5 3 4.5 3 5 5 7. 5 3.5 3.5 6. 5 4 5 3.5 4.5 2.5 3.5 5.5  6 6 3 4 5 1 1 3 4 6 4 3 2 5 3 3 5 4  5 4.5 3.5 5 3.5 6 6 5 5 6.5 11 6. 5 4 7.5 6.5 4  1 5 5 1 4 3 2 1 3 3 1 3 2 4 5 3  5  6  3 2 1 3 5 1 1 5 3 3 5 3 2 2 3 1 3 3  2 2 3 3 2.5 3 3 1 2 1.5 1.5 3 2.5 1 1 3 1 1  2 2 1 1 2 2 3 1 1.5 1.5 1.5 1.5 1 1 1 5 1 1  3 5 5 1.5 3 5 3 2 5 5 1 5 1 5 5 3  3 3 1.5 3 1 1.5 1.5 3 1 1.5 1 3 3 1.5 2 1.5  3 1.5 1 3 1 2 1.5 3 1 2 2 5 5 2 1.5 1  S a l t Marsh 2 2 2 2 2 2 2 2 2 2 2.5 2 3.5 2.5 4 2 2 2 Wade * s Bog  Carex p l u r i f l o r a Apargidium'' boreale Agrostis aequivalvis Carex obnupta Sanguisorba officinalis Kalmia polifolia V a c c i n i u m oxy c o c c u s Carex canescens Drosera rotundifolia Ledum groenlandicum Trientalis arctica Empetrum nigrum Myrica gale Tofieldia glutinosa Gentiana douglasiana Linnaea borealis  2 2 2 2 2 1 1.5 2 3 1 2.5 1 1 2 4 1.5  176 TABLE 19.  (Continued)  1 6  7  8  9  10  1  1  1  2  13  Ik  3 2 3 3 3 4 2 3 2 3 3 2 2 2 4 2 2 2  4 3 5 4 4 3 3 2 2 2 3 2 3 2 1 1 1 1  15  16  E=IPR-  5 4 2 1.5 2 3 1.5 3 3 4 2 4 3 2 2 2 4 2  3 2 1 1 1 3 2 1 2 2 1 1 1 2 1 1 5 1  58.5 51.0 42. 5 45.0 47.5 42.0 40. 0 41.0 44 . 5 51.5 42.0 48. 5 40 . 5 38 . 0 36.0 45 . 5 40 . 5 35.5  1  S a l t Marsh :•..~?5 -~ a -s6 • . r.. • -. 2;5 6 I 3.5. 7 I 4 6 l 5 6 I 2 6 7 I 2.5 3 2.5 l i 3 4 3 6 l 3 l 3 i 3 5 I 5 4 l 5 3 I 5 1 2 7 I I 3.5 3.5 I 3 3  -P3  3 3 3 3 3 3 3 4 3 3 4 2. 5 2 1.5 3 2 3  7 7 2 2 1 1 1 1 5 7 1 7 1 2 1 7 1 1  3 3 2 2 2 2 2 2 2.5 3 2 3 2 2 2 3 2 2  r a n g e : 3 5 . 5 _ - 58.5 unweighted x = 4 3.8 w e i g h t e d x = 47.2 Wade's Bog 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  .  2.5 5 4 2.5 4.5 4 2.5 3.5 5 5 3 5 5 4 5 2.5  7 4 7 7 4 5 5 7 1.5 5 3 7 7 4 5 4.5  3 4 3 3 3.5 4 4 3 2 4 4 3 3 4 4 4  1 7 3 1 2 3 2 1 1 2 7 7 7 2 2 7  2 3 2 2 1 2 2 2 2.5 1 3 3 3 1 1.5 3  2 5 3 2 3.5 5 4 2 4 5 2 4 3.5 4 3 4  4 5 5 4 5 3 3 3 5 4 5 3 2 4 4 2  1 2 1 1 3;5 4 2.5 3 2 3 2 4 3.5 4 1 3.5  3 1 2 2 4 2 3 2 4 3 2.5 1 1 1 1 1  43. 5 58.0 49. 0 41. 0 46 . 5 51.5 44. 5 43.5 43.5 52.0 51. 0 61. 5 52.0 51. 0 51.5 46.5  177 TABLE 19  (continued)  1  Species  2  3  4  5  6  4. 5 6.5 6 5 5 6 5. 5 6.5 4.5  7 1 2 1 1 2 2 6 3  3 5 5 1 1 3 1 5 5  2 3 1 3 3 1 1. 5 3 2  2 1 1 1 1. 5 1 1 2 1.5  4 4.5 5 5 3.5 3.5 6.5 6 5 6 6.5 11 5 7. 5 4 6.5 3 5.5 6.5 3.5 4.5 5 4.5 4.5 5  2 5 1 1 5 4 3 2 3 3 3 1 1 4 3 1 5 2 6 6 7 1 3 3 1  1 5 1.5 3 5 3 5 3 5 5 5 1 2 5 3 5 3 1 5 3 3 1 5 5 1  3 3 3 3 1.5 1 1.5 1.5 1 1.5 3 1 3 1.5 1.5 3 3 1.5 3 2 2 3 2 2 3  5 1.5 3 3 1 1 2 1.5 1 2 5 2 3 2 1 1 2 1 2 2 2 1 1.5 1. 5 1.5  Wade's Bog ( c o n t i n u e d ) 2 2 1.5 2 2 1 1 2 2  Maianthemum d i l a t a t u m Rhynchospora alba Vaooinium vitis-idaea Soivpus oespitosus Junous s u p i n i f o r m i s Vaccinium uliginosum Gaultheria shallon Gentiana sceptrum Coptis a s p l e n i f o l i a  Ogg' s Bog 1  Myrica gale Apargidium boreale Carex obnupta Carex p l u r i f l o r a Agrostis aequivalvis Sanguisorba officinalis Ledum groenlandicum V a c c i n i u m oxy c o c c u s Drosera rotundifolia Kalmia p o l i f o l i a Empetrum nigrum Trientalis arctica Carex canescens Tofieldia glutinosa Linnaea borealis Rhynahospora alba Plantago macrocarpa Gaultheria shallon Gentiana sceptrum Calamagrostis nutkaensis Maianthemum d i l a t a t u m Scirpus cespitosus Coptis asplenifolia Coptis trifolia Juncus s u p i n i f o r m i s  1 2 2 2 2 2 1 1.5 3 1 1 2.5 2 2 1.5 2 2 1 2 2 2 2 2 2 2  TABLE 19.  178  (Continued)  1 6  1o  I I  1 2  1 3  1 it  1 5  1 6  S = IPR l  Wade's Bog ( c o n t i n u e d ) 1 1 1 1 1 1 1 1 1  3 3 2.5 4.5 2 5 5 5 3  3.5 7 5 7 7 5 5 5 3  4 3 4 3 3 4 4 4 3.5  7 1 2 1 1 2 1 2 3  3 2 2 1.5 2 2 1 2 1.5  4 2 4 2 4 4 4 4 2.5  1 2 2 2 1 1 1 3 1  3 2 3 3.5 1 4 2 1 2  1 1 1 1 2 2 1 1 1  51.0 42.5 43 . 0 39. 5 37.5 44. 0 37.0 52.5 39 . 5  range : 36. 0 - 61.5 unweighted x = 47. 0 w e i g h t e d x = 48 . 5 Ogg ' s Bog 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  5 5 2. 5 2.5 4 4.5 5 2.5 5 4 5 3 3.5 4 2.5 3 5 5 5 4 3 4.5 3 3 2  7 4 7 7 7 4 5 5 1.5 5 7 3 7 4 4.5 7 7 5 5 7 3. 5 7 3. 3 7  3 4 3 3 3 3.5 4 4 2 4 3 4 3 4 4 3 3 4 4 3 4 3 3.5 4 3  7 7 1 1 3 2 2 2 1 3 7 7 1 2 7 1 1 1 2 7 7 1 3 3 1  3 3 2 2 2 1 1 2 2.5 2 3 3 2 1 3 2 2 1 2 3 3 1.5 1.5 2.5 2  3.5 5 2 2 3 3.5 5 4 4 5 4 2 2 4 4 2 3.5 4 4 2.5 4 2 2.5 2 4  4 5 4 4 5 5 4 3 5 3 3 4 3 3 3 2 3 2 3 2 2 2 2 2 2  3.5 2 1 1 1 3.5 3 2.5 2 4 4 2 3 4 3. 5 2 1 2 1 2 3 3.5 2 3 1  1 1 2 3 2 4 3 3 4 2 1 2.5 2 1 1 1 1 1 1 2 1 1 1 1 2  54.0 58 . 0 41. 0 43.5 49. 0 46.5 52.0 44. 5 43 . 5 51.5 61. 5 50 . 0 43. 5 50.0 47.5 42.5 45.5 38.0 52.5 52.0 52.0 39 . 5 40.5 42.5 37.5  TABLE 19.  179  (continued)  Species  1  2  3  5  6  Ogg's Bog ( c o n t i n u e d ) 2 D e s c h a m p s i a ce s p i t o s a Gentiana douglasiana 4 Vaccinium ovatum 1 Vaccinium vitis-idaea 1.5 Cornus unalaschkensis 1.5 Vaccinium uliginosum 1 Eephrophyllidium crista-gaH i 2 Eriophorum polystachion 2 Carex p a u c i f l o r a 2  3.5 6.5 6 6 5.5 6 8.5 5 5  6 5 2 2 3 2 1 2 1  3 5 5 5 3 3 2 2 1.5  2 2 1 1 1.5 1 2 3 2  2 1.5 1 1 1.5 1 2 3 3  2 6 1 4 4 2 7 2 6 4 5 2 4 5 4 3 2 4 5 1 7 5 4 3 5  1 3 1 5 5 3 5 5 5 5 3 1 3 3 3 3 1 2 3 2 3 3 1 3 3  2 1.5 1 3 2 2 1 1 2 2 3 2 3 2 3 3 3 3 2 2 1 3 3 3 3  2 1.5 1 1.5 2 1.5 1.5 1 2 2 5 2 1 2 1.5 2 4 1.5 2 3 1 2 1. 5 5 1.5  B l a c k w a l l Meadow Valeriana sitchensis Festuca viridula Lupinus latifolius Erigeron peregrinus Anemone occidentalis Potentilla flabellifolia Erythronium grandiflorum Vaccinium scoparium Claytonia lanceolata Arenaria capillaris Antennaria lanata Veronica cusickii Agoseris aurantiaca Phleum alpinum Arnica latifolia Luzula hitchcockii Thalictrum occidentale Achillea millefolium Trisetum spicatum Carex r o s s i i Elymus glaucus Silene parryi Arnica mollis Poa e p i l i s Senecio integerrimus  2 2 2 2 2 2 3 1 3 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  4 3. 5 6 4.5 4 3. 5 6 6 4 5.5 3.5" 4.5 4.5 3.5 5 3 3.5 4.5 3.5 5 3.5 6 5 3.5 5  180 TABLE 19.  (continued)  16 7  8  9  1 0  I I  Ogg's Bog 1 1 1 1 1 1 3 1 1  5 5 5 2.5 2.5 5 3.5' 2 3  6 5 5 5 4 5 3.5 7 7  1 3  l >t  15  1 6  Z = IPR l  (continued) 7 2 2 2 7 2 2 1 1  3 4 4 4 4 4 4 3 3  12  3 1.5 1 2 3 2 2 2 2  2.5 3 4 4 4 4 2 5 3  1 1 2 2 1 1 1 1 1  5 1 1 3 2.5 4 2 2 2  3 1 1 1 3 2 1 3 1  55.0 49. 5 41. 0 43.0 48.0 44.0 41. 5 44. 0 . 38.5  r a n g e : 37.0 _ 61.5 unweight ed x = 46.6 weij j h t e d x = 49 . 8 B l a c k w a l l Meadow 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  4 5 5 4 5 4 5 5 5 5 4 4 5 4 4 2 3 4 5 5 5 5 4 1 5  4 7 5 4 3 4 5 5 4 4 4 4 4 7 4 7 7 4 7 7 3 6 4 7 4  4 3 4 4 4 4 4 4 4 4 3 4 4 3 4 3 3 4 3 3 2 4 4 3 4  2 3 7 7 2 6 2 3 2 7 7 3  1 2 3 3 3 2 3 2 2.5 3 3 2 3  1 7 6 5 7 7 1 1 2 7 1 7  1 3 2 3 3 3 2 2 2 3 3 3  5 2 3 5 5 2 2 4 2 4 5 3 5 4 5 2 2 5 4 2 2 3 5 2 5  4 5 5 5 5 5 5 4 5 4 4 4 3 3 2 2 1 2 2 2 1 2 2 1 2  3 1 4 4 2 1 3 1 5 4 1 2 3 5 4 1 3 5 5 3 3 1 2 2 3.5  2 3 5 3 1 2 2 1 1 4 3 1 1 2 3 1 2 4 3 2 5 1 3 4 2  43. 0 49 . 5 54. 0 60.0 50.0 45. 0 55 . 5 46.0 53.5 60.5 56.5 41. 5 53.5  48.5 55.5 43.0 45.5 56.0 57. 5 43.0 42.5 48 . 0 51.5 44. 5 56.0  TABLE 19.  181  (Continued)  Species  B l a c k w a l l Meadow Hieraoium gracile Luzula spiaata Sedum lanceolatum Castilleja miniata Penstemon procerus Pedioularis bracteosa Phlox d i f f u s a Potentilla diversifolia Carex s p e c t a b i l i s Epilobium alpinum Delphinium nuttallianum Castilleja parviflora Ranunculus eschscholtzii S i b b a l d i a procumbens Microsteris gracilis Junous drummondii Eydrophyllum fendleri Senecio triangularis Vaccinium deliciosum  (continued) 2 2 2 2  1.5 2 1.5 2 2 2 2 2 2 2 4 2 2 2 1  4.5 3 4 6 4 4 3. 5 3.5 5 4.5 4 6 4 3.5 4 5 4.5 5 6  5 2 4 3 3 4 4 2 2 2 4 3 5 2 4 1 4 6 2  5 3 5 5 5 . 5 5 1 1 3 3 5 3 5 5 1 3 3 3  3 3 1 1 2 1 1 2 3 1 2.5 1 2 1 1 2. 5 2 3 1  1 2 2 2 1 2 1 1.5 3 1 1 2 1.5 1. 5 1 2 2 1. 5 1  TABLE 19.  1o  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  4 5 4 5 4 5 5 5 3 3 5 5 5 3 4 4 4 5 5  182  (Concluded)  4 7 5 6 4 5 5 4 7 2.5 5 5 3 2 2.5 7 5 4 5  3 3 4 4 4 4 4 4 3 3 4 4 4 3 3.5 3 4 4 4  Il  1 2  1 3  1 "t  1 5  1 6  1 6  Z = IPR l  7 1 7 7 2 7 7 5 1 1 3 7 2 2 1 1 3 7 3  3 2 3 3 1 3 3 2 2 2.5 2.5 3 2 2 2.5 2-..5 '2 3 2  5 2 4 5 4 3 2 2 1 5 4 5 2 2 4 4 2 5 4  1 2 1 2 1 2 1 1 1 1 1 2 1 1 1 1 1 1 1  4 3 3 4 2 3. 5 3 3.5 3 4 3 3 4 3 3 2.5 2 3.5 1  3 1 3 4 3 1 1 4 3 3 4 3 2 1 1 1 1 1 1  55.5 42. 0 53.0 60 . 0 42. 5 52.5 48.0 43.5 40 . 0 39 . 5 49 . 0 •57.0 43.5 35. 0 43.5 40.5 42. 5 55.0 41. 0  r a n g e : 3 5 . 0 _ - 6 0.5 unweighted x = 48.6 weighted x = 50.6  'Arranged i n o r d e r of d e c r e a s i n g  importance  value.  183 systems, might be expected t o have l e s s v a r i a b l e p o p u l a t i o n s than comparable o u t c r o s s i n g s p e c i e s  ( S t e b b i n s 1957a; Grant 1958).  However, a l a r g e body o f r e c e n t e v i d e n c e suggests t h a t some i n b r e e d i n g s p e c i e s have m a i n t a i n e d a h i g h l e v e l o f p o p u l a t i o n v a r i a b i l i t y presumably through o c c a s i o n a l o u t c r o s s i n g  between  s t r o n g l y homozygous b i o t y p e s ( A l l a r d 1965; Kannenberg and A l l a r d 1967;  J a i n and M a r s h a l l 1967; R o l l i n s 1967; A l l a r d , J a i n and  Workman 1968; J a i n 1969; Kondo 1972, inter  alia).  S p e c i e s o f Cyperaceae, Gramineae, J u n c a c e a e ,  and L i l i a c e a e  have average I . P . R . ' s o f 4 1 . 4 , 4 8 . 3 , 4 0 . 2 , and 5 2 . 5 , r e s p e c t i v e l y . Average I . P . R . ' s f o r r e p r e s e n t a t i v e s o f some common n o r t h temperate d i c o t y l e d o n o u s f a m i l i e s a r e :  Caryo-  p h y l l a c e a e ( 4 5 . 4 ) ; Compositae ( 5 5 . 1 ) ; E r i c a c e a e , i n c l u d i n g Empetrum  ( 4 6 . 2 ) ; Ranunculaceae  nigrum  Scrophulariaceae  ( 4 5 . 1 ) ; Rosaceae  (42.9);  ( 5 0 . 7 ) . The p h y l o g e n e t i c s i g n i f i c a n c e o f  these f i g u r e s w i l l not be s p e c u l a t e d on.  TABLE 20. Average community I . P . R . ' s .  Community  S a l t Marsh Wade's Bog Ogg's Bog B l a c k w a l l Meadow  x,  unweighted  43.8 47.0 46 . 6 48.6  x,  weighted 1  47.2 48.5 49.8 50.6  Weighted by m u l t i p l y i n g the unweighted I . P . R . f o r each s p e c i e s by i t s c o r r e s p o n d i n g I . V . and d i v i d i n g the community sum o f t h e s e p r o d u c t s by the average I . V . f o r t h a t community.  184 The  most s t r i k i n g g e n e r a l i z a t i o n t h a t emerges from t h i s  a n a l y s i s i s t h a t the d i f f e r e n t f a c t o r s  i n a species'  r e c o m b i n a t i o n system f r e q u e n t l y work i n o p p o s i t i o n t o one another but a r r i v e at an e v o l u t i o n a r y compromise between fitness for  and f l e x i b i l i t y .  different  species'  T h i s compromise i s u s u a l l y d i f f e r e n t  s p e c i e s and tends t o be c o r r e l a t e d w i t h  ecological strategy  which i t i s a c o n s t i t u e n t . opposing f a c t o r s The  the  and the type o f v e g e t a t i o n o f  Some examples o f the i n t e r p l a y o f  are g i v e n i n T a b l e 2 1 .  situation i n different  s p e c i e s i s i n s t r u c t i v e . For  example, the e r i c a c e o u s shrub Kalmia  polifolia  has a l o n g  g e n e r a t i o n t i m e , moderate v e g e t a t i v e r e p r o d u c t i o n v i a s h o r t rhizomes and t i l l e r i n g , it  and i s p a r t i a l l y s e l f - c o m p a t i b l e ; but  i s d i p l o i d , has a h i g h b a s i c chromosome number, showy  f l o w e r s t h a t are h i g h l y o u t c r o s s e d , and m i n u t e , l i g h t seeds w i t h good d i s p e r s i b i l i t y . Spergularia autogamous  , though  (most o f i t s f l o w e r s are c l e i s t o g a m o u s ) and a  t e t r a p l o i d with f a i r l y is  canadensis  s m a l l chromosomes and clumped p o p u l a t i o n s ,  an annual t h a t u s u a l l y has a few chasmogamous f l o w e r s on  each p l a n t , and has s m a l l , g l a n d u l a r - p u b e s c e n t ,  slightly-  winged seeds and l a r g e p o p u l a t i o n s . Even Poa cusickii epilis  var.  , though i t appears t o reproduce p r i m a r i l y by  agamospermy, has l a r g e chromosomes and i s d i o e c i o u s and w i n d p o l l i n a t e d , so t h a t whenever t h i s Poa happens t o  reproduce  s e x u a l l y , i t i s l i k e l y t o r e l e a s e a l a r g e amount o f recombinational v a r i a b i l i t y  ( C l a u s e n 1954, 1 9 6 1 ) .  185 TABLE. 21. Combinations o f o p p o s i n g r e g u l a t o r y  F a c t o r s promoting v s . f a c t o r s r e s t r i c t i n g recombination  factors.  Examples  s h o r t g e n e r a t i o n s , good seed d i s p e r s a l , large populations vs. autogamy, clumped p o p u l a t i o n s  Spergularia Microsteris  d i o e c y o r s t r o n g dichogamy, anemop h i l y vs. high polyploidy, small chromosomes  Triglochin maritimum, Juncus balticus, Myrica gale, Thalictrum occidentale  l a r g e chromosomes, s e l f - i n c o m p a t i b i l i t y , o u t c r o s s i n g vs.. p o l y p l o i d y , vegetative reproduction  canadensis, gracilis  many Gramineae and Compositae  showy f l o w e r s , s e l f - i n c o m p a t i b i l i t y , Lupinus latifolius, l a t i f o l i a , Arnica h i g h b a s i c numbers, f r e q u e n t ' i n t e r specific h y b r i d i z a t i o n , ecotypic d i f f e r e n t i a t i o n vs. polyploidy, s m a l l chromosomes  Arnica mollis  d i p l o i d y , h i g h b a s i c chromosome number v s . s e l f - c o m p a t i b i l i t y r e l a t i v e l y inconspicuous flowers '  Glaux maritima, Stellaria humifusa, Tofieldia glutinosa, Drosera rotundifolia  h i g h b a s i c number, s e l f - i n c o m p a t i b i l i t y vs. high polyploidy, small chromosomes  Trientalis arctica, Lupinus latifolius  h i g h b a s i c number v s . g e n e r a t i o n time  E r i c a c e a e , Empetrum  long  l a r g e chromosomes, a n e m o p h i l y , frequent h y b r i d i z a t i o n v s . polyploidy, inbreeding  Elymus brachy  d i o e c y , wind p o l l i n a t i o n v s . low b a s i c numbers, p o l y p l o i d y , extensive vegetative reproduction  Distichlis  mon^eey,, ^dieta^gagrjf,;; wind; - p p l l i r t  Carex lyngbyei, C. p l u r i f l o r a  :  ^nafiLOBi HPS . . . s p a l l ' Ghrompsome^Sr,  good d i s p e r s a l , h y b r i d i z a t i o n v s . autogamy, p o l y p l o i d y , s m a l l chromosomes  glaucus, an the rum  Epilobium  nigrum  Hordeum  spicata  C.  alpinum  obnupta,  186 TABLE 21.  (Continued)  F a c t o r s promoting v s . f a c t o r s r e s t r i c t i n g recombination ,  Examples  l a r g e chromosomes, d i p l o i d y , dichogamy, anemophily v s . low b a s i c number, s e l f compatibility  Plantago  good d i s p e r s a l , h y b r i d i z a t i o n v s . autogamy, p o l y p l o i d y , s m a l l chromosomes  Epilobium  showy f l o w e r s , w e l l - d e v e l o p e d e n t o m o p h i l y , good d i s p e r s a l v s . self-compatibility  Valeriana sitohensis Delphinium nuttallianum,  In  alpinum  3  Ericaceae  l a r g e chromosomes, showy, o u t crossed f l o w e r s , ecotypic d i f f e r e n t i a t i o n vs. self-compatib i l i t y , poor d i s p e r s a l l a r g e chromosomes, d i p l o i d y , showy, entomophilous f l o w e r s , good dispersal vs. s e l f - c o m p a t i b i l i t y , no h y b r i d i z a t i o n , l i t t l e or no ecotypic differentiation  maritima  Claytonia lanceolata, Erythronium grandiflorum  Gentiana douglasiana \G. soeptrum, Anemone ocoidentalis  summary, t h i s a n a l y s i s has shown t h a t t h e r e  differences  i n the r e c o m b i n a t i o n p o t e n t i a l s  but t h a t t h e s e d i f f e r e n c e s  are a p p a r e n t l y  species  are  of d i f f e r e n t  species  not g r e a t . The  g e n e r a l i z a t i o n t h a t autogamous s p e c i e s have more r e c o m b i n a t i o n systems than comparable  3  xenogamous  restricted or  seems v a l i d . However, s p e c i e s w i t h r e s t r i c t e d  n a t i o n p o t e n t i a l do not dominate the v e g e t a t i o n  outcrossing recombi-  o f any o f  the  study c o m m u n i t i e s ; i n d e e d , they are u s u a l l y v e r y minor elements (cf.  T a b l e s 3, 4 , 5, 6 w i t h T a b l e Table 1 9 ) . F u r t h e r m o r e ,  no  187 s i g n i f i c a n t d i f f e r e n c e was found between l e v e l s o f p o t e n t i a l r e c o m b i n a t i o n w i t h i n any o f the communities. T h i s f i n d i n g at odds w i t h M o s q u i n ' s (1966) t h e s i s  is  that species of harsh  p h y s i c a l environments have r e p r o d u c t i v e s p e c i a l i z a t i o n s f o r reducing genetic v a r i a b i l i t y ;  i . e . , closed recombination  systems. Of c o u r s e , i t i s d i f f i c u l t  t o d e c i d e which o f the  four  communities has the h a r s h e s t p h y s i c a l environment. The c l i m a t e of the T o f i n o a r e a may be c l a s s e d as warm, t e m p e r a t e , and r a i n y ; t h a t o f the s u b a l p i n e meadow as c o n t i n e n t a l , c o l d , and humid but summer dry ( a f t e r  K r a j i n a 19 6 5 ) . The o v e r a l l c l i m a t e  of the s u b a l p i n e meadow might thus be c o n s i d e r e d h a r s h e r .  But  t h e r e are l o c a l m i c r o e n v i r o n m e n t a l c o m p l i c a t i o n s , The s a l t marsh i s s u b j e c t e d t o g r e a t ranges i n d a i l y t e m p e r a t u r e ,  and  the p l a n t s are p e r i o d i c a l l y baked by t h e sun and f l o o d e d by s a l t water (Chapman 1960, 19 6 4 ) . D u r i n g the growing s e a s o n , plants  i n the s u b a l p i n e meadow are exposed t o g r e a t d i u r n a l  temperature f l u c t u a t i o n bo'thaabpveaand  below ground (Kuramoto  and B l i s s 197 0; B a l l a r d 1972),and may a l s o e x p e r i e n c e  moisture  s t r e s s on s h a l l o w , w e l l - d r a i n e d s o i l s (Eady 1971). Only c o a s t a l sphagnum bog has a t r u l y equable c l i m a t e , but  the  its  o v e r a l l p h y s i c a l e n v i r o n m e n t , c h a r a c t e r i z e d by a low n u t r i e n t s t a t u s and a w a t e r l o g g e d , p o o r l y oxygenated s u b s t r a t e (Gorham 1957 ; S m a l l 19 7 2a .. 8 b),,. .must .be. ..considered . c o m p a r a t i v e l y h a r s h F u r t h e r m o r e , as was p o i n t e d out i n the s e c t i o n on l e v e l s of p o l y p l o i d y , e n v i r o n m e n t a l r i g o r i n c l u d e s r e l a t i v e of environmental f l u c t u a t i o n s  amplitude  and the i r r e g u l a r i t y o f t h e s e  f l u c t u a t i o n s , as w e l l as average c o n d i t i o n s o f the e n v i r o n -  188 mental complex such as c l i m a t i c means and n u t r i e n t l e v e l s . The different  l e v e l s o f p o l y p l o i d y i n the t h r e e v e g e t a t i o n t y p e s  seemed t o be b e s t e x p l a i n e d by d i f f e r e n t degrees of e n v i r o n mental i n s t a b i l i t y . However, the l o g i c o f S e c t . I I I - C does not a p p l y t o t h e f i n d i n g s o f t h e I . P . R . , o f which p o l y p l o i d y but one a s p e c t .  is  D i f f e r e n t s e l e c t i o n p r e s s u r e s have been  o p e r a t i n g i n s a l t marshes, sphagnum b o g s , and s u b a l p i n e meadows, and d i f f e r e n t t y p e s o f s p e c i e s s t r a t e g i e s have e v o l v e d as a r e s u l t  ('see s e c t .  have h a r s h e n v i r o n m e n t s , i n at l e a s t  and community f e a t u r e s  I V ) . A l l f o u r communities some r e s p e c t s .  But t h e r e  i s no i n d i c a t i o n t h a t the d i f f e r e n t t y p e s o f s e l e c t i o n  differ  i n o v e r a l l s e v e r i t y , a l t h o u g h one ( t h a t o f the s u b a l p i n e meadow) may be caused more by b i o t i c f a c t o r s t h a n a n o t h e r  ( t h a t of the  s a l t m a r s h ) . I t i s not s u r p r i s i n g t h a t the I . P . R . ' s f o r the f o u r communities are not s i g n i f i c a n t l y  different.  What i s more, t h i s a n a l y s i s says n o t h i n g d i r e c t l y about the a c t u a l l e v e l s o f g e n e t i c v a r i a b i l i t y w i t h i n the  species  p o p u l a t i o n s . To get some measure o f t h i s i t would be n e c e s s a r y t o study enzyme polymorphisms or seed p r o t e i n v a r i a b i l i t y or some such m o l e c u l a r a p p r o a c h . But even i f one community had more s p e c i e s w i t h more h e t e r o z y g o s i t y t h a n the  other  c o m m u n i t i e s , one s t i l l c o u l d not m a i n t a i n t h a t t h a t community had b e t t e r adapted s p e c i e s t h a n the o t h e r s , adaptedness  since species  can be a c h i e v e d e i t h e r by i n d i v i d u a l a d a p t a b i l i t y  (a h o m e o s t a t i c genotype) or by g e n e t i c a d a p t a b i l i t y ( d i v e r s i t y of genotypes)  (Dobzhansky 1968; c f . Gooch and Schopf 1972;  L e v i n t o n 1 9 7 3 ) . Bradshaw (1971) puts the problem i n p r o p e r p e r s p e c t i v e : "There i s l i t t l e d i f f e r e n c e i n essence  between  189  normal s i t u a t i o n s and extreme environments from an e v o l u t i o n a r y point of view". N e v e r t h e l e s s , i t would be e x t r e m e l y i n t e r e s t i n g t o o t h e r p r e d o m i n a n t l y herbaceous v e g e t a t i o n types t o  subject  similar  a n a l y s i s . Would, s a y , the e x t r e m e l y d i v e r s e , t a l l g r a s s  prairies  of the Midwest or the c o a s t a l p r a i r i e s o f Texas have h i g h e r average I . P . R . ' s than the study communities? Would a r c t i c t u n d r a or the d i s t u r b e d , weedy C e n t r a l V a l l e y g r a s s l a n d o f C a l i f o r n i a have l o w e r a v e r a g e . I . P . R . ' s ? What about  other  community c o m p a r i s o n s ; e g . , Great B a s i n v s . Sonoran d e s e r t s , C a l i f o r n i a c h a p a r r a l v s . A u s t r a l i a n t h o r n scrub? S u r e l y here i s a tremendous f i e l d  for future  investigation.  190 Summary, Discussion, and Conclusions.  The f i n d i n g s o f the p r e s e n t  i n v e s t i g a t i o n are b e s t  summarized and c o n t r a s t e d i n a balance sheet (Table 2 2 ) . G e n e r a l i n d i c a t i o n s are t h a t i n t e r s p e c i f i c c o m p e t i t i o n i n c r e a s e s from sphagnum bogs t o s a l t marsh t o s u b a l p i n e meadow, w h i l e s t r e s s o f the p h y s i c a l environment i n c r e a s e s  from sphagnum bogs  t o s u b a l p i n e meadow t o s a l t marsh. These i n d i c a t i o n s are w h o l l y c o n s i s t e n t , but s e v e r a l g e n e r a l t r e n d s  the  not  are e v i d e n t i n  Table 22. A more s p e c i f i c summary f o l l o w s : 1. The v e g e t a t i o n o f a s a l t marsh, two sphagnum b o g s , and a s u b a l p i n e meadow were d e s c r i b e d by means o f t a b l e s o f importance v a l u e s and by m o d i f i e d s p e c i e s 2. The p o p u l a t i o n s t r u c t u r e  constellations  o f the i n d i v i d u a l s p e c i e s  has  been a s s e s s e d w i t h a D / d i n d e x o f a g g r e g a t i o n . A g g r e g a t i o n i n c r e a s e s as e n v i r o n m e n t a l h e t e r o g e n e i t y  and  p h y s i c a l s t r e s s i n c r e a s e , and d e c r e a s e s as s u c c e s s i o n proceeds and i n t e r s p e c i f i c c o m p e t i t i o n i n c r e a s e s . 3. I n d i c e s o f a s s o c i a t i o n and c o r r e l a t i o n have been used to s t a t i s t i c a l l y assess i n t e r s p e c i f i c r e l a t i o n s h i p s . I n t e r s p e c i f i c a s s o c i a t i o n and c o r r e l a t i o n , b o t h p o s i t i v e and n e g a t i v e , i n c r e a s e w i t h i n c r e a s i n g e n v i r o n m e n t a l heterogeneity  and c o m p e t i t i o n .  4. Chromosome counts were made f o r most o f the s p e c i e s , and l e v e l s o f p o l y p l o i d y f o r b o t h the f l o r a and v e g e t a t i o n of a l l f o u r communities were e s t a b l i s h e d .  Levels of poly  p l o i d y appear t o be c o r r e l a t e d w i t h e n v i r o n m e n t a l r i g o r  TABLE 22. R e s u l t s and i n d i c a t i o n s from v a r i o u s aspects o f the i n v e s t i g a t i o n ; a l l i n d i c a t i o n s are r e l a t i v e .  Community  S a l t Marsh  Species-area curves  >.  co  cu  M-l •H CO  CO cu Cl)  &  CU  U •H  > •H TJ  >i  >,  O  Wade's Bog  rG  +->  Ogg's Bog  Blackwall Meadow  •H O rtj  ft  Population s t r u c t u r e (D/d index)  high s a l i n i t y coastal s a l t marsh, m a i n l y i n r a p i d expansion and accretion  s p e c i e s most a g g r e g a t e d ; s t r o n g habitat zonation; harsh p h y s i c a l environment; moderate c o m p e t i t i o n  c o a s t a l sphagnum bog a t or approaching climax  l e a s t a g g r e g a t i o n ; weak i n t e r s p e c i f i c competition; successi o n a l maturity  c o a s t a l sphagnum b o g , f a i r l y early in succession  strong aggregation; microtopog r a p h i c m o s a i c i s m ; weak competi t i o n ; s u c c e s s i o n a l youth  l u s h , more or l e s s mesic, Cascadian s u b a l p i n e meadow; c l i m a x (?)  moderate a g g r e g a t i o n ; m i c r o topographic mosaicism; strong competition; successional maturity  cu  ft  bO  o ft o bO -H a o •H o >, •H u rtf O  u rd  S  >,  rrj  O  +->  +->  cu  +->  g o  Community d e s c r i p t i o n s  •H cu  r -4  Correlation  Levels of polyploidy  Community  Association  S a l t . Marsh  heterogeneous moderate environment; competition tight microsite specificity greatest physical stress  most p o l y ploidy ; greatest "rigor" ( h i s t o r i c a l and physical)  +/- homogeneous weak environment; competition loose m i c r o s i t e specificity intermediate stress  least polyploidy ; least rigor  heterogeneous weak environment; competition .tight microsite specificity - intermediate stress  least polyploidy ; least rigor  heterogeneous strong environment; competition tight microsite specificity lowest p h y s i c a l s t r e s s  much p o l y ploidy ; moderate-strong rigor  Wade's Bog  Ogg's Bog  Blackwall Meadow  Flowering phenology  CD CO  Pollination ecology  weak i n t e r s p e c i f i c competition for pollination vectors; primarily abiotic pollination  rd CD  P. O CD T 3  moderate c o m p e t i t i o n b o t h b i o t i c and abiotic pollination  T 3 O  •r-i  U ft CD  hO  moderate c o m p e t i t i o n b o t h b i o t i c and abiotic pollination  u  o I—I 4 H MH O  -H M| CD  rH  a)  ca0| -rd & CD >  intense competition; predominantly b i o t i c pollination  o  DO  OP OP  M pu  ft x o t, s; pj  >d  CD  OP 1  4  3  P)  4 ft 4  rV O O  O  pj 3  4 ft 4  3  cn H - H pj cn H  P)  fD  PJ  (D  H-  r+  O  H-  rt  HO  to  3  T j OP CD 1  H  rt 4  H-  cn p . pP) cn H  3 PJ rt o tr H -  +  cn 3  rt ^ 3  ft  cn  4  H ' O  H- O  cn 3  *d  CD  4  OP  0  H  3  0  rt  OJ H-  <+•<  3  O  rt  fD  H-  v..  O  rtW OP H - CD 1  ft  O  1— 1  4  H - (D O rt  3  rt CD  O  3  H-  PJ HH  competition  average s p e c i e s v a r i a b i l i t y  O H-  cn  •d  CD  4  cn P) H  CD  o  H-  H  H-  OP  1  OP fD  3  rt cn  ^  O  3  rt  0 3  O O  •<  2  average n i c h e s i z e decreases  interspecific  rt  P) fD h- rt P)  4  O  3  O  pj 4  H - fD  H-  O  rt  4  cn H - cn pj cn >d o  O  O  cn  3 4 ft H.rjq  3  rt  Hi  0 cn 3 4  H- rt  H-  O  tr ex, H H- H- O  3 tr>d  H- rt  O  rt 4 3 0 pJ 3 4 OP H-  p.  tru  (C  OP 1  cn  4  cn Hpi cn H o  O  H - CD  O  pj  to  OP  ft p f l CD  H'fu  rt  -• cn  O  o o  sh  H- O  CO 3  H  CD  tD  H H  pj  ft  -• cn  P) O  an  pj  So  3 fD  HO  tr  increases  CD  decreases  rt  tr CD  o 4  cn cn cD rt p-  4 3  3  o o  o 3  ft H ' H (D H O 4  OP  P) OP PJ  O  O  3  4  3  H-  H-O rt P)  rt  fl) I  "< H cn  *d ^ • CD rt H> rt HO  O  rt 4 O  3  OP  CD  O O  3  CD  oO  fD  H O  •d 3 fD  rt rt  H-  O  3  cn OP cn H -  o  -  s: fD  pj  H  PJ  ft  X-  H-  cn rt  H-  3 O rt I  CD < O CD O •d 3 H CD CD O rt cn OP H-  rt  PO  3  01  s: CD PJ  cn  >0  cn  Si  CD H - rt  HO  CD PJ 3 4 O X H- O H- I H 3 H i 3 P) OP H- O 4 O ft H - (D CD rt O  H O  PJ  0  H-  cn rt  4 ^ 0  O P )  ft  W  s! cn  3 rt  •d  H-  3 O rt I  CD  CD  rt H H- 3  rt  H O O HiOP  H-  Cn O  *d  rt fD O • CD O  3 4I CH D  cn  i n d e x of dominance d e c r e a s e s species d i v e r s i t y ^  increases  C  s t r e s s o f p h y s i c a l environment s t a b i l i t y increases  decreases (?????)  P)  H  tr CD  ft HHi HI  CD  4  CD  3  rt  H-  PJ  rt HO  3  PJ O  3