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Taxonomic investigation of selected species of Staurastrum meyen and Staurodesmus teiling from lakes… Contant, Hélêne 1984

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TAXONOMIC INVESTIGATION OF SELECTED SPECIES OF STAURASTRUM MEYEN AND STAURODESMUS TEILING FROM LAKES OF THE LOWER FRASER VALLEY, BRITISH COLUMBIA by HELENE CONTANT B.Sc, Universite De Montreal, 1973 M.Sc. University Of Waterloo, 1976 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES Department Of Botany We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l 1984 © Helene Contant, 1984 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the requ i rements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Co lumb i a , I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s tudy . I f u r t h e r agree 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 copy i ng o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g ran ted by the head o f my department o r by h i s o r her r e p r e s e n t a t i v e s . I t i s unde r s tood t h a t copy ing o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l no t be a l l owed w i thou t my w r i t t e n p e r m i s s i o n . Department o f B o t a n y  The U n i v e r s i t y o f B r i t i s h Co lumbia 1956 M a i n M a l l Vancouve r , Canada V6T 1Y3 Date A p r i l 2 7 , 1984 \ DE-6 (3/81) i i Abstract An investigation of selected taxa of Staurastrum and Staurodesmus (Desmidiaceae, Desmidiales, Chlorophyta) was undertaken to help c l a r i f y their taxonomy. The study was conducted on samples co l l e c t e d in the lower Fraser Valley ( B r i t i s h Columbia). Sampling was done over a 2 1/2 year period in four main lakes (Jacobs, Munday, Lost and Como Lakes) with physico-chemical analyses (pH, temperature, i r r a d i a t i o n , a l k a l i n i t y , dissolved oxygen, calcium, n i t r a t e , phosphate) used to characterize the habitats. Observations of f i e l d material revealed nine new records and 56 new d i s t r i b u t i o n records of Staurastrum for B r i t i s h Columbia. One hundred and t h i r t y - s i x clones comprising 18 taxa of Staurastrum and two taxa of Staurodesmus out of 310 clones of desmids successfully isolated in culture were studied. Morphological variation of the clonal isolates was studied with the l i g h t microscope and the scanning electron microscope (SEM). C e l l dimensions and c e l l radiation were measured in each of the 136 clones studied and the lengthrwidth r a t i o ( L / l ) , standard deviation and c o e f f i c i e n t of var i a t i o n were calculated for each. For the 1 9 9 taxa studied, more than 350 publications were consulted. These included o r i g i n a l descriptions, records of d i s t r i b u t i o n of taxa studied as well as i n f r a s p e c i f i c and related taxa. Comparison of variations observed in culture and f i e l d material were made with the l i t e r a t u r e and 33 synonyms were proposed. Growth and morphological studies in di f f e r e n t environmental i i i conditions (medium, i r r a d i a t i o n , temperature, pH) were car r i e d out with a t r i r a d i a t e clone of Staurastrum inflexum Brebisson (clone HC 18). Growth rate varied in the d i f f e r e n t environmental conditions tested but morphological variation was usually not affected. An analysis of variance showed no s i g n i f i c a n t difference between c e l l size or c e l l radiation in di f f e r e n t conditions, although higher pH (6.20 compared to 4.62) produced more tetraradiate c e l l s . Attempts to induce sexual reproduction in d i f f e r e n t environmental conditions were unsuccessful. Control clones of St. gladiosum Turner and Cosmarium botr y t i s Meyen ex Ralfs from culture c o l l e c t i o n s did show conjugation in similar conditions. i v Tab le of Contents A b s t r a c t i i L i s t of Tab l e s v i i L i s t of F i g u r e s ix L i s t o f P l a t e s - . • • ••• . x A c k n o w l e d g e m e n t • . . •'. • . x i Chapter I INTRODUCTION 1 A. CLASSIFICATION OF DESMIDS 1 B. REPRODUCTION 12 C. MORPHOLOGICAL VARIATION 17 D. GOALS OF THE PRESENT STUDY . . . . 21 Chapter II STUDY AREAS 22 A. JACOBS LAKE 22 B. MUNDAY LAKE 24 C. LOST LAKE 26 D. COMO LAKE 26 E. OTHER SITES 27 Chapter III MATERIALS AND METHODS 32 A. FIELD PROCEDURES 32 1. PHYSICO-CHEMICAL FACTORS 32 a . PH 33 b. Temperature 33 c . L i g h t 33 d . D i s s o l v e d Oxygen 34 e. A l k a l i n i t y 34 f . Ca l c ium 35 g . N i t r a t e And Phosphate 35 2. ALGAL COLLECTION TECHNIQUES 37 a . P l ankton Samples 37 b. Pe r i phy ton Samples 37 c . Sediment Samples 38 d . P r e s e r v a t i o n Of Specimens 38 B. LABORATORY PROCEDURES 38 1. ALGAL CULTURING 38 2. ALGAL ISOLATION 39 3. SEXUALITY EXPERIMENTS 40 V 4. GROWTH EXPERIMENTS 42 5. ICONOTHEQUE 44 6. MORPHOLOGICAL VARIATION 45 Chapter IV RESULTS AND DISCUSSION 50 A. PHYSICO-CHEMICAL FACTORS 50 B. DISTRIBUTION OF ALGAL GENERA IN LAKES STUDIED 60 1 . JACOBS LAKE 60 2. MUNDAY LAKE 61 3. LOST LAKE 63 4. COMO LAKE 64 5. OTHER SITES 65 C. DISTRIBUTION OF STAURASTRUM SPP. AND STAURODESMUS SPP. IN LAKES STUDIED 70 D. SEXUALITY EXPERIMENTS 76 1. CLONES ISOLATED 7 6 2. CLONES FROM CULTURE COLLECTIONS 7 7 E. GROWTH PATTERN OF STAURASTRUM INFLEXUM (CLONE HC 18) IN DIFFERENT ENVIRONMENTAL CONDITIONS 83 F. MORPHOLOGICAL VARIATION OF STAURASTRUM INFLEXUM (CLONE HC 18) IN DIFFERENT ENVIRONMENTAL CONDITIONS 89 1. CULTURE MEDIA 89 2. IRRADIATION 92 3. TEMPERATURE 92 4. PH 93 G. SUMMARY OF RESULTS AND DISCUSSION 100, Chapter V DESCRIPTION AND VARIATION OF SELECTED STAURASTRUM AND STAURODESMUS TAXA 102 A. INTRODUCTION TO TAXONOMIC TREATMENT AND KEY 102 B. STAURASTRUM BREBISSONII VAR. BREBISSONII 107 C. STAURASTRUM GLADIOSUM VAR. GLADIOSUM 120 D. STAURASTRUM ALTERNANS VAR. ALTERNANS 139 E. STAURASTRUM MURICATUM VAR. MURICATUM 156 F. STAURASTRUM AVICULA VAR. AVICULA 170 G. STAURASTRUM PROBOSCIDEUM FORMA MINOR INCLUDING ST. PROBOSCIDEUM VAR. PROBOSCIDEUM 193 H : S T A U R A S T R U M S E X C O S T A T U M V A R . P R O D U C T U M I N C L U D I N G S T . S E X C O S T A T U M V A R . S E X C O S T A T U M 2 1 2 I . S T A U R A S T R U M C R E N U L A T U M V A R . C R E N U L A T U M 2 2 1 J . S T A U R A S T R U M M A N F E L D T I I V A R . P A R V U M I N C L U D I N G S T . M A N F E L D T I I V A R . M A N F E L D T I I 2 3 0 K . S T A U R A S T R U M V E S T I T U M V A R . V E S T I T U M . . 2 4 4 L . S T A U R A S T R U M I N F L E X U M V A R . I N F L E X U M 2 6 0 M . S T A U R A S T R U M T E T R A C E R U M V A R . T E T R A C E R U M 2 7 1 N . S T A U R A S T R U M F U R C I G E R U M V A R . F U R C I G E R U M A N D S T A U R A S T R U M F U R C I G E R U M F O R M A E U S T E P H A N U M 2 8 6 0 . S T A U R A S T R U M S E N A R I U M V A R . S E N A R I U M 3 0 1 P . S T A U R A S T R U M A R A C H N E V A R . A R A C H N E • 3 1 5 Q . S T A U R A S T R U M O P H I U R A V A R . O P H I U R A A N D S T \ P E N T A C E R U M V A R . P E N T A C E R U M 3 2 6 R . S T A U R A S T R U M G R A L L A T O R I U M V A R . F O R C I P I G E R U M I N C L U D I N G S T . G R A L L A T O R I U M V A R . G R A L L A T O R I U M 3 4 8 S . S T A U R O D E S M U S M U C R O N A T U S V A R . D E L I C A T U L U S I N C L U D I N G S T D . M U C R O N A T U S V A R . M U C R O N A T U S 3 5 3 T . S T A U R O D E S M U S D E J E C T U S V A R . D E J E C T U S 3 6 6 Chapter V I S U M M A R Y A N D C O N C L U S I O N 3 8 1 A . S U M M A R Y 3 8 1 B . C O N C L U S I O N 3 9 2 L I T E R A T U R E C I T E D 3 9 7 A P P E N D I X A - S A M P L I N G D A T E S F O R T H E M A I N S I T E S 4 0 9 A P P E N D I X B - R E F E R E N C E S U S E D I N I C O N O T H E Q U E 4 1 1 A P P E N D I X C - N U M E R I C A L L I S T O F C L O N E S S T U D I E D 4 3 5 A P P E N D I X D - D R A W I N G S , I N C L U D I N G P U B L I S H E D I L L U S T R A T I O N S O F T A X A S T U D I E D 4 3 8 v i i L i s t of Tables 1. C l a s s i f i c a t i o n of Zygnematales .10 2. Supplementary c o l l e c t i n g s i t e s and physico-chemical data 30 3. Nutrient content of media used for growth experiments 49 4. Irradiation measurements 59 5. Species of Staurastrum (S_t. ) and Staurodesmus (Std. ) from lakes of the Lower Fraser Valley 71 6. Clones and environmental conditions used for sexual experiments 79 7. . Summary of techniques used for desmid conjugation by di f f e r e n t workers 81 8. Average c e l l dimensions of Staurastrum inflexum (clone He 18) in di f f e r e n t environmental conditions 95 9. C e l l radiation of Staurastrum inflexum (clone He 18) in d i f f e r e n t environmental conditions 97 10. C e l l radiation of Staurastrum inflexum (clone HC 1 8 ) in d i f f e r e n t media and in the f i e l d 99 11. C e l l dimensions and radiation of St. brebissoni i ..118 12. C e l l dimensions and radiation of St. gladiosum ....137 13. C e l l dimensions and radiation of St. alternans ....154 14. C e l l dimensions and radiation of St. muricatum ....167 15. C e l l dimensions and radiation of St. avicula 189 16. C e l l dimensions and radiation of St. proboscideum var. minor 207 17. C e l l dimensions and radiation of St. sexcostatum var. productum 219 18. C e l l dimensions and radiation of St. crenulatum ...228 19. C e l l dimensions and radiation of St. manfeldtii var. parvum 242 v i i i 20. C e l l dimensions and radiation of St. vestiturn 258 21. C e l l dimensions and radiation of St. inflexum 267 22. C e l l dimensions and radiation of St. tetracerum ...283 23. C e l l dimensions and radiation of St. furciqerum ...299 24. C e l l dimensions and radiation of St. senarium 313 25. C e l l dimensions and radiation of St. arachne 324 26. C e l l dimensions and radiation of St. ophiura 342 27. C e l l dimensions and radiation of St. pentacerum ...343 28. C e l l dimensions and radiation of St. grallatorium var. fore ipigerum 352 29. C e l l dimensions and radiation of Std. mucronatus var. delicatulus 362 30. C e l l dimensions and radiation of Std. dejectus .... 378 ix L i s t of Figures 1. I l l u s t r a t i o n s of terms used in text 11 2. Location of sampling s i t e s in the Lower Fraser Valley 29 3. Physico-chemical data for Jacobs Lake 55 4. Physico-chemical data for Munday Lake 56 5. Physico-chemical data for Lost Lake 57 6. Physico-chemical data for Como Lake 58 7. Growth rate of Staurastrum inflexum (clone HC 18) in di f f e r e n t media 87 8. Growth rate of Staurastrum inflexum (clone HC 18) in di f f e r e n t media and at d i f f e r e n t i r r a d i a t i o n s 88 X L i s t o f P l a t e s 1. S t a u r a s t r u m b r e b i s s o n i i v a r . b r e b i s s o n i i H ? A 2 . S t a u r a s t r u m g l a d i o s u m v a r . g l a d i o s u m 138A 3 . S t a u r a s t r u m a l t e r n a n s v a r . a l t e r n a n s ; . . 1 5 5 A 4 . S t a u r a s t r u m m u r i c a t u m v a r . m u r i c a t u m 16%A 5 . S t a u r a s t r u m a v i c u l a v a r . a v i c u l a 192A 6 . S t a u r a s t r u m p r o b o s c i d e u m f . m i n o r . ' . 2>MA. 7 . S t a u r a s t r u m s e x c o s t a t u m v a r . p r o d u c t u m 2 2 0 A 8 . S t a u r a s t r u m c r e n u l a t u m v a r . c r e n u l a t u m 229A 9 . S t a u r a s t r u m m a n f e l d t i i v a r . p a r v u m 243A 1 0 . S t a u r a s t r u m v e s t i t u m v a r . v e s t i t u m 259A 11 . S t a u r a s t r u m i n f l e x u m v a r . i n f l e x u m 270A 1 2 . S t a u r a s t r u m t e t r a c e r u m v a r . t e t r a c e r u m 285A 1 3 . S t a u r a s t r u m f u r c i g e r u m v a r . f u r c i g e r u m a n d S t a u r a s t r u m f u r c i g e r u m f o r m a e u s t e p h a n u m 3 0 0 A 1 4 . S t a u r a s t r u m s e t i a r i u m v a r . s e n a r i u m 314A 1 5 . S t a u r a s t r u m a r a c h n e v a r . a r a c h n e 3 2 5 A 1 6 . S t a u r a s t r u m o p h i u r a v a r . o p h i u r a a n d S t a u r a s t r u m p e n t a c e r u m v a r . p e n t a c e r u m 3 4 7 A 1 7 . S t a u r o d e s m u s m u c r o n a t u s v a r . d e l i c a t u l u s 36-5A 1 8 . S t a u r o d e s m u s d e j e c t u s v a r . de.j e c t u s a n d S t a u r o d e s m u s g r a l l a t o r i u m v a r . f o r c i p i g e r u m . . 3 8 0 A xi Ac knowledgement I would l i k e to thank the members of my t h e s i s committee, Dr. K.M. Cole, Dr. R.E Dewreede and Dr. P.J. H a r r i s o n , f o r t h e i r h e l p and advice i n the completion of t h i s t h e s i s . S p e c i a l thanks are due to Dr. P.J. H a r r i s o n f o r the use of h i s AutoAnalyser. I am t h a n k f u l to Dr. J.R. S t e i n , my s u p e r v i s o r , f o r her i n v a l u a b l e h e l p , e s p e c i a l l y i n the w r i t i n g of the t h e s i s . I acknowledge the use of the computer p r i n t o u t by S t e i n and Borden (unpublished) through the Department of Botany, U n i v e r s i t y of B r i t i s h Columbia (UBC). I thank Mr. L a z l o Veto who a d v i s e d me i n the use of the e l e c t r o n microscope, Ms. V i c t o r i a Lyon-Lamb who helped me s o l v e d computer problems and the s t a f f of the I n t e r l i b r a r y loan s e r v i c e of Woodward l i b r a r y , UBC. I am a l s o g r a t e f u l to the numerous people who helped me with f i e l d and l a b o r a t o r y work, e s p e c i a l l y L i z Drance, P a u l i n e Monck, D a n i e l Nagy and Dennis R u t h e r f o r d . I acknowledge the f i n a n c i a l h e l p of the Quebec Government (Bourse de 1'enseignement s u p e r i e u r ) , the N a t u r a l , A p p l i e d and H e a l t h Sciences Committee of UBC and the N a t i o n a l Sciences and E n g i n e e r i n g Research C o u n c i l of Canada (Grant 1035 to Dr. J.R. S t e i n ) . 1 I . INTRODUCTION A. CLASSIFICATION OF DESMIDS The Zygnematales (Chlorophyta) form a f a i r l y homogenous order of the Chlorophyceae (Smith 1950, Bold and Wynne 1978) or Conjugatophyceae (Fott 1971, Mix 1975). They have the important c h a r a c t e r i s t i c of non-flagellated reproductive c e l l s . The name Conjugales, which is sometimes used instead of Zygnematales, refers to the special mode of reproduction. The Zygnematales are either u n i c e l l u l a r or filamentous. They have a wall composed of three layers and possess large chloroplasts and pyrenoids. Many Zygnematales secrete a mucous layer. Some authors find these c h a r a c t e r i s t i c s to be so important that they designate the Zygnematales as a d i s t i n c t class, the Conjugatophyceae (Fott 1971; Table 1B), Zygnemaphyceae (Round, 1971) or Zygophycees (Bourrelly 1966, 1972). The Zygnematales t r a d i t i o n a l l y include three families: the Mesotaeniaceae (saccoderm or false desmids), the Desmidiaceae (placoderm or true desmids) and the Zygnemataceae (Smith 1950, Bourrelly 1966, Bold and Wynne 1978; Table 1A). The Zygnemataceae are c h a r a c t e r i s t i c a l l y filamentous and the c e l l s do not have any median c o n s t r i c t i o n , pore or ornamentation. They are represented by such ubiquitous genera as Mougeotia, Zygnema and Spirogyra. The Mesotaeniaceae, which are u n i c e l l u l a r , are named saccoderm desmids because their wall consists of one piece; that i s the c e l l is not composed of two semicell joined together at the equatorial c o n s t r i c t i o n , or 2 isthmus, as in the Desmidiaceae ( F i g . 1). They a l s o lack pores in the c e l l w a l l , c h a r a c t e r i s t i c of the true or placoderm desmids. They d i f f e r from the Zygnemataceae by the absence of true filamentous s p e c i e s . The Desmidiaceae have a w a l l composed of two p a r t s which forms an e q u a t o r i a l c o n s t r i c t i o n , the isthmus. Pores are present i n the c e l l w a l l ( F i g . 1). Modern u l t r a s t r u c t u r a l s t u d i e s r e v e a l d e t a i l s of the true desmid c e l l that suggest m o d i f i c a t i o n i n the c l a s s i f i c a t i o n . D i f f e r e n t orders or f a m i l i e s have been c r e a t e d to i n c l u d e one or two s l i g h t l y d i f f e r e n t genera (e.g., the Gonatozygaceae, Table 1B). Mix (1975) proposed a c l a s s i f i c a t i o n summarizing previous f i n d i n g s by other i n v e s t i g a t o r s and her own u l t r a s t r u c t u r a l r e s e a r c h (Table 1C). T h i s c l a s s i f i c a t i o n r e s t s on d e t a i l s which c o u l d not be d i s t i n g u i s h e d before the advent of e l e c t r o n microscopy. Although f u r t h e r i n v e s t i g a t i o n s may b r i n g more changes to her c l a s s i f i c a t i o n , i t i s based on s o l i d evidence and i s accepted i n the present study. Mix (1975) i n c l u d e d the Mesotaeniaceae i n the Zygnematales and r e c o g n i z e d two sub-orders of Desmidiales, the Ar c h i d e s m i d i i n e a e and the Desmidiineae. The f i r s t sub-order i n c l u d e s the f a m i l i e s Gonatozygaceae, C l o s t e r i a c e a e and Peniaceae. The Gonatozygaceae do not have a c e l l w a l l made of two p a r t s , but s i n c e they possess a pore system and a s c u l p t u r e d w a l l , they are seen as placoderm desmids. The C l o s t e r i a c e a e and Peniaceae have a w a l l c o n s i s t i n g of two or more p a r t s and show only a s l i g h t e q u a t o r i a l c o n s t r i c t i o n or none. Furthermore, they do not shed t h e i r 3 primary wall. The Desmidiaceae, which are the only family of the sub-order Desmidiinae, have a well developed system of pores and a c e l l wall composed of two parts forming a d i s t i n c t i v e equatorial c o n s t r i c t i o n . Members of this family shed their primary wall. The genera Staurastrum and Staurodesmus belong to t h i s family. The sta r t i n g point for a l l desmid nomenclature is Ralfs' B r i t i s h Desmidieae (1848; see International Code of Botanical Nomenclature, ICBN 1978, A r t i c l e 13.1g). The genus Staurastrum was created by Meyen (1829) for a tetraradiate specimen (or specimens) of St. paradoxum. Ralfs' (1848, p. 119) description of the genus Staurastrum i s , "Frond simple, constricted at the middle; end view angular, or c i r c u l a r with a lobato-radiate margin, or, rarely, compressed with a process at each extremity. "Frond mostly minute, simple, more or less constricted at the middle, and thus forming two segments, which are often somewhat twisted, generally broader than long, and in many species elongated l a t e r a l l y into a process, so that the c o n s t r i c t i o n on each side i s a roundish or angular sinus; in other respects the front view shows the segments quite e n t i r e . "The end view varies in form: in most of the species i t i s triangular or quadrangular, and the angles are either rounded or elongated into rays; in some i t i s c i r c u l a r with five or more processes forming marginal rays; in a few species i t is compressed and the extremities terminate by a process..." Ralfs' concept was modified by subsequent authors. West and West (1912, p. 119) define Staurastrum as follows: "...the genus Staurastrum i s primarily distinguished by the r a d i a l symmetry of the c e l l s as seen in v e r t i c a l view. It embraces species of more varied character than any other genus of desmids. 4 " A l l kinds of spine forms occur in the genus, from those in which the whole surface of the c e l l is covered with spines. A l l gradations occur from smooth to granulate species, from granulate to asperulate and minutely-spined forms, and from these to coarsely-spined forms. " . . . A l l attempts to s p l i t up t h i s genus on natural p r i n c i p l e s have e n t i r e l y f a i l e d . The relationships of the numerous species are too complex and close, so that only a r b i t r a r y lines of demarcation can be drawn..." The concept of Staurastrum has stayed r e l a t i v e l y unchanged since 1912. F r i t s c h (1930) proposed the creation of the genus Cosmostaurastrum for Cosmarium-like Staurastrum. Palamar-Mordvintseva (1976) divided Staurast rum into four genera, Cylindiastrum, Comoastrum, Raphidiastrum and Staurastrum. But the creation of the genus Staurodesmus by T e i l i n g (1948) is the only scheme that has gained wide recognition. According to Brook (1959a), the o r i g i n a l description and drawing of St.. paradoxum Meyen are inadequate and the material of the Jenner Herbarium in the B r i t i s h Museum from which the drawing was supposedly done, is of St. micron W. West. Brook suggests that St. paradoxum be considered as nominum  inqui rendum. In 1939, Irenee-Marie noted that the genus Staurastrum "comporte autant d'especes et autant d'individus que tous les autres genres ensemble, s i l'on f a i t exception du genre Cosmarium pour le nombre des especes, et du genre Closterium pour la quantite des individus." T e i l i n g (1948, 1950, 1967) suggested that radiation patterns (Fig. 1D) in desmids are not stable c h a r a c t e r i s t i c s 5 and cannot be considered as acceptable taxonomic c r i t e r i a . C e l l s with angular spines which are morphologically similar are c a l l e d Arthrodesmus i f they are biradiate, but Staurastrum i f they are t r i - to p l u r i r a d i a t e . Dichotypical c e l l s (Fig.lD), also termed Janus-forms ( T e i l i n g 1950), where the two semicells of the same desmid c e l l bear d i f f e r e n t patterns of radiation, are given as examples of the close relation between the two genera. On t h i s basis, T e i l i n g proposed a reorganization of the genera Arthrodesmus and Staurastrum. He placed the smooth monospinous taxa (with one spine at each angle), in the new genus Staurodesmus, whatever their pattern of radiation. Because of the complexity of the genus, Staurastrum is often the l a s t treated genus in f l o r a s , and sometimes is not included at a l l . Krieger published only two parts of his monograph on desmids in "Rabenhorst's Kryptogamen Flora" (Krieger 1937, 1939) and never published on Staurastrum. However, the genus Cosmarium was treated in subsequent publications (Krieger and Gerloff 1962, 1965, 1969). Ruzicka (1977, 1981) has not yet treated the genera Staurastrum and Staurodesmus in "Die Desmidiaceen Mitteleuropas". Prescott and co-workers (see Prescott et a l . 1972, 1975, 1977, 1981, 1982 and Croasdale et a L 1983) just published the part on Staurastrum in the monograph on North American desmids. They opted not to recognize the genus Staurodesmus u n t i l i t is proved to be a natural taxon. However, they do not specify what is meant by "natural taxon". In my opinion, the discovery of dichotypical c e l l s where one semicell belongs to Staurastrum and 6 the other to Arthrodesmus, prove that these genera are not natural; yet both genera are accepted by Prescott e_t a l . (1982). The c h a r a c t e r i s t i c s defining the genus Staurodesmus do not appear to be shared by other genera of desmids; no c e l l s or dichotypical c e l l s of Staurodesmus showing features used to define another genus have been reported. I thus recognize the genus Staurodesmus as v a l i d . Thus Staurastrum is a neglected member of the desmids. The reason for this situation seems to l i e in i t s complexity. Many of the Staurastrum taxa are poorly described, and subsequent misinterpretation of the o r i g i n a l species has led to much confusion. The technical means available to observe microscopic algae were very limited in the nineteenth century and at the beginning of the twentieth century, when most species of Staurastrum were described. Since a wide body of l i t e r a t u r e exists for the desmids, many taxa may have been named simply because the author ignored the existence of a previous publication of his taxon, under a di f f e r e n t name. Other taxa probably represent only non-permanent morphological variations of known e n t i t i e s . It i s d i f f i c u l t to define what i s a desmid species. Sexual reproduction in desmids i s rare and i s unknown in many taxa; th i s i s thus an aspect which cannot be part of a species d e f i n i t i o n of desmids. Features used to distinguish between species or i n f r a s p e c i f i c taxa vary between taxa. F r i t s c h (1953) notes that "there i s a widespread lack of balance, many of the newer species d i f f e r i n g from one another to a less degree than 7 do the so-called v a r i e t i e s or forms of other species." Many such examples are found in my study: a large number of i n f r a s p e c i f i c taxa have been described for Staurastrum tetracerum. For example, St. tetracerum var. maximum Messikommer (Pi. K F i g . 13) d i f f e r s from the type species (PI. K F i g . 3) by i t s larger size, more open sinus, and the presence of apical verrucae. On the other hand, St. denticulatum var. denticulatum (Nageli) Archer d i f f e r s from St. avicula var. avicula Brebisson ex Ralfs because i t has granules only at the angles, whereas the difference between St. lunatum var. lunatum Ralfs and St. avicula var. avicula, is the presence of one spine at each angle in the former and two spines at each angle in the l a t t e r . These examples show that what appear to be minor variations can be used to distinguish between two species, whereas more numerous differences can be c l a s s i f i e d at the v a r i e t a l l e v e l . Furthermore, I found that the features used to d i f f e r e n t i a t e between St. avicula var. avicula, St. lunatum var. lunatum and St. dent iculatum var. dent iculatum are not stable; l i t e r a t u r e reports also support these findings. This i n s t a b i l i t y was not observed with St• tetracerum var. tetracerum. Because of the large number of Staurastrum taxa described, i t i s d i f f i c u l t to come up with d e f i n i t e c r i t e r i a which could be used to d i f f e r e n t i a t e the s p e c i f i c and i n f r a s p e c i f i c levels for a l l the taxa. To do so, one must have a very good grasp of the features distinguishing the numerous taxa involved, and be able to reevaluate these taxa in the l i g h t of the new c r i t e r i a 8 established. This is a major work which has not yet been attempted. As a basis for the reevaluation of the taxa I studied, I considered that a c h a r a c t e r i s t i c which varies in clonal (progeny from a single c e l l ) culture and i s thus not genetically determined, does not make a good taxonomic c r i t e r i o n . Such variations are c a l l e d "modificatio", "morpha", "facie s " or "monstrositas" by Gronblad and Ruzicka (1959). The key included in Chapter V of t h i s thesis highlights the features used to d i f f e r e n c i a t e between the taxa studied. The shape of the semicell, the presence or absence of angular or accessory processes, the direction of the processes, the type and pattern of ornamentation and the size and radiation range, are a l l ch a r a c t e r i s t i c s which were used to dis t i n g u i s h between the taxa. These c h a r a c t e r i s t i c s proved stable enough in clonal culture to be used as taxonomic features. A few studies have included basic SEM (scanning electron microscope) work to complement observations of the morphology of the c e l l with the li g h t microscope or TEM (transmission electron microscope) (Coute and Rino 1975, Lorch 1978, Lott et a l . 1972, Naef et a l . 1978, Capdevielle and Coute 1980, Coute and T e l l 1981). Lyon (1969), Pickett-Heaps (1973, 1974, 1975), Gough (1978) and Gough et. a l . (1976), worked at developing technical methods for processing desmids for SEM observation. Although the SEM i s becoming an important tool in the study of desmid taxonomy and morphology, the time and costs involved may prevent or slow down i t s generalized use in f l o r i s t i c and taxonomic studies. 9 TEM work with desmids generated new information useful in c l a s s i f i c a t i o n of desmids, and also to the knowledge of their l i f e cycle. For example, Drawert and Mix (1961), Gerrath (1968), Lott et al^ (1972), Coute and Rino (1975), Mix (1969, 1972, 1975), Mix and Manshard (1977), Chardard (1977) worked on the ultrastructure of the c e l l wall, pore apparatus or internal structure of desmids. Ueda (1972), Dubois-Tylski (1973a, 1973b), Abadie and Dubois-Tylski (1974), Pickett-Heaps (1975), Noguchi (1978), Vidyavati (1982) investigated u l t r a s t r u c t u r a l d e t a i l s of c e l l d i v i s i o n and d i f f e r e n t parts of the c e l l cycle. 10 TABLE 1 CLASSIFICATION OF ZYGNEMATALES A. Smith 1950 Bold and Wynne 1978 Class Chlorophyceae iOrder Sub-order Zygnematales Family Zygnemataceae Mesotaeniaceae Desmidiaceae B. Fott 1971 Class Order Conjugatophyceae Mesotaeniales Zygnematales Gonatozygales Desmidiales Sub-order Family Mesotaeniaceae Gonatozygaceae Desmidiaceae Mix 1975 Class Order Conjugatophyceae Zygnematales (saccodermae) Desmidiales (placodermae) Sub-order Family Zygnemataceae Mesotaeniaceae Archidestnldiineae Gonatozygaceae Peniaceae Closteriaceae Desmidiineae Desmidiaceae 11 gure 1 - I l l u s t r a t i o n s of terms used i n t e x t HA process isthmus semicell apex spines granules sinus supraisthmial granules A. Front view spine apical ornamentation-pore-subapical or lateral ornamentation process accessory process double verruca mucro B. Ap ica l , vert ical or end view C. Ce l l division i.bi radiate —penta ii.triradiate iii. tetraradiate v II > *— t r i iv. dichotypical cell tri-pentaradiate D. Radiation (vertical view) 1 2 B. REPRODUCTION The l i f e cycle of desmids is haplobiontic and haploid with a zygotic meiosis (Bold and Wynne 1978, p. 13). The vegetative c e l l s are haploid and produce haploid gametes which are amoeboid. Two gametes, each produced by a d i f f e r e n t c e l l , fuse to form a d i p l o i d zygote which undergoes meiosis to produce haploid vegetative c e l l s and complete the cycle. C e l l d i v i s i o n in the placoderm desmids i s unique to algae due to the two-part structure of the c e l l wall and i t s often highly refined ornamentation. Brook (1981) recognized four types of c e l l d i v i s i o n in the placoderm desmids, the Hyalotheca-, Bambusina-, Closterium- and Cosmariurn-types. The last type applies to the constricted placoderm desmids and thus to Staurastrum and Staurodesmus. During the process of d i v i s i o n of the Cosmarium-type, the isthmial part of the c e l l where the septum i s formed w i l l begin to elongate at di f f e r e n t stages during karyokinesis or sometimes after completion of nuclear d i v i s i o n ( F i g . I C i ) . The isthmial area w i l l continue to grow and bulge eventually to form two new semicells which w i l l l a t e r develop the normal wall ornamentation c h a r a c t e r i s t i c of the species ( F i g . 1 C i i - i i i ) . The secondary wall i s deposited i n t e r n a l l y to the primary wall which w i l l eventually be shed (Mix 1972, see her f i g . 22). The secondary wall develops the pore system and the pattern of ornamentation c h a r a c t e r i s t i c of each taxon. If during c e l l d i v i s i o n the septum is incompletely formed, t h i s may result in the formation of aberrant c e l l s with two 1 3 semicells at d i f f e r e n t stages of morphological development sandwiched between the two parental semicells. Formation of asexual spores in the desmids i s rare. It often results from f a i l u r e of gamete fusion during conjugation, but formation of akinetes within a vegetative c e l l has also been observed. Brandham (1965a) gave a good account of the di f f e r e n t types of desmid asexual spores. Sexual reproduction in nature i s rarely reported. For his "Flore desmidiale de la region de Montreal", Irenee-Marie (1939) recorded 527 taxa of desmids, but found only three occurrences of zygospores: that i s , for Desmidium swartzi i Agardh, Cosmarium  moniliforme (Turpin) Ralfs var. punctata Lagerheim and Xanthidium antilopaeum Brebisson var. minneapoliense Wolle. West and West (1912) and West et a l . (1923) reported that the zygospores of only 43 of the 169 Staurastrum known to England had been found. Of the 99 species without processes, 29 were found with zygospores, that is about 29%, while 14 zygospores of the 70 species with processes were observed, that i s 20%. More elaborate Staurastrum bearing processes are more commonly found in the plankton and less l i k e l y to undergo sexual reproduction. Coesel and Texeira (1974) stated that, "It i s an established fact that sexual reproduction (by means of conjugation) of the large majority of the desmids occurs only sporadically in nature or has not been observed at a l l . " Sexual reproduction in unialgal desmid cultures has been achieved by Starr (1955) with Cosmarium botr y t i s var. subtumidum Wittrock using a C0 2 enrichment method. Subsequent 14 authors succeeded in inducing sexual reproduction with unialgal cultures of placoderm desmids: Cook (1963), Brandham (1967), Brandham and Godward (1964), Kies (1968), Lippert (1967), Pickett-Heaps and Fowke (1971), Ling and Tyler (1972) Watanabe (1979), Dubois-Tylski (1977), Blackburn and Tyler (1980, 1981). Brandham and Godward (1964) used, among others, homothallic clones of St. dent iculatum (Nageli) Archer and St. polymorphum Brebisson ex Ralfs, whereas Winter and Biebel (1967) induced sexuality in an he t e r o t h a l l i c clone of St. gladiosum Turner. Ichimura and Watanabe (1976) and Watanabe and Ichimura (1978a, 1978b) applied a new approach based on sexual i s o l a t i o n , to the species concept in desmids. They worked with the Closterium peracerosum-str iqosum-1ittorale complex. The Charles-Stalker i s o l a t i o n index (Stalker 1942) developed for Drosophila was applied to determine degrees of sexual i s o l a t i o n between individuals or groups of individuals similar in shape and dimensions. When male and female of dif f e r e n t species of Drosophila were mixed, the index, which is concerned with f e r t i l i z e d females, is defined as: % conspecific - % a l i e n % conspecific + % a l i e n Watanabe and Ichimura (1978a) grouped clones of Closterium of the above named complex, from d i f f e r e n t locations in Japan on the basis of morphological v a r i a t i o n . The i s o l a t i o n index 1 5 showed no sexual i s o l a t i o n in one group (=0) and negative sexual i s o l a t i o n (-1) in another group. Negative sexual i s o l a t i o n would mean that some clones showed a higher rate of conjugation when mixed with morphologically similar clones from another location than when mixed with morphologically similar clones from the same location. Watanabe and Ichimura (1978b) mentioned a previous occurrence of negative sexual i s o l a t i o n in Drosophila, although the phenomenon has not been c l e a r l y explained. Isolation between morphological groups ranged from complete to p a r t i a l . Coesel and Texeira (1974) randomly selected 120 strains of 16 desmid genera, including 17 Staurastrum clones, and subjected them to Starr's technique for inducing sexual reproduction in desmids (Starr 1955). Only three clones showed conjugation, none were Staurastrum. Those conjugating were: Closterium  moniliferum, C. limneticum Lemmermann var. f a l l a x Ruzicka and Micrasterias p a p i l l i f e r a Brebisson. Coesel and Texeira agreed that Starr's success was due to the fact that, "Attempts have been made to isolate sexual strains only from natural populations of desmids in which there was already some evidence of sexual reproduction" (Starr 1955). Coesel and Texeira noted that most available sexual clones of desmids belong to the Mesotaeniaceae and to the genus Closterium. Sexuality seems to be a more r e s t r i c t e d phenomenon in the more advanced desmid genera. Coesel and Texeira (1974) stated that, "According to F r i t s c h (1930) there is a general tendency in t h i s group, p a r t i c u l a r l y in the more advanced 16 ( i . e . morphologically most differentiated) genera, towards the elimination of sexual reproduction." In his introduction to the f i r s t International Desmid Symposium, Mollenhauer (1975) stated that "in desmids, there is a marked tendency to abandon sexual processes in the course of evolut ion." 1 7 C. MORPHOLOGICAL VARIATION Much morphological variation has been observed in desmids. As early as 1899, G.S. West published a paper "On variation in the Desmidieae and i t s bearings on their c l a s s i f i c a t i o n " , in which he stresses that: "On the examination of a large number of specimens of one species from many widely separated l o c a l i t i e s , c ertain examples are sure to be found which exhibit some variation from the t y p i c a l plant, and without a very careful study of the species i t i s d i f f i c u l t to determine whether th i s v a r i a t i o n i s merely of a transitory or accidental nature, the specimen being the direct offspring of some type-form, or whether i t constitutes a true variety produced by a gradual evolution from the o r i g i n a l type." Present-day desmid taxonomists stress the importance of evaluating the v a r i a b i l i t y of a species to avoid describing taxa based on single specimens or non-permanent morphological v a r i a t i o n . Gronblad and Ruzicka (1959) noted that the d e f i n i t i o n of a desmid taxon is d i f f i c u l t to formulate and is the result of the subjective interpretation of the investigators. Thus they recommended naming non-permanent v a r i a b i l i t i e s with non-taxonomic terms, such as : "modificatio", "morpha", "fac i e s " , "monstrositas", rather than describing new v a r i e t i e s and forms. The terms "morpha" and "fa c i e s " have been used commonly by such authors as Croasdale, Forster, P e t e r f i and Thomasson. V a r i a b i l i t y in morphology in the f i e l d has been noted as early as 1887 with Euastrum and Micrasterias by De Wildeman. Variation in Staurastrum has been observed by diff e r e n t 18 investigators. Reynolds (1940) observed the seasonal v a r i a t i o n of radiation (see F i g . 1D) in specimens i d e n t i f i e d as Staurastrum paradoxum from the Swithland Reservoir close to Leicester in England. Gronblad and Scott (1955) described the variation of populations of St. bibrachiatum Reinsch from two I t a l i a n lakes and among material co l l e c t e d by A.M. Scott from M i s s i s s i p i (U.S.A.), and consequently emended the d e f i n i t i o n of the species. Lind and Croasdale (1966) described the v a r i a b i l i t y of St. sebaldi Reinsch var. ornatum Nordstedt from the Sasumma Reservoir in Kenya, A f r i c a . Brook and Hine (1966) examined 200 specimens of St. f reemani i W. et G.S. West from a pond in New Guinea, and on the basis of their results, proposed a revision of the species and i t s v a r i e t i e s . P e t e r f i (1972) worked on the v a r i a b i l i t y of populations of St. monticulosum (Brebisson) Ralfs, St. subavicula (West) W. et G.S. West and St. forficulatum Lundell from Romanian bogs. Following Gronblad and Ruzicka (1959) suggestion, he described non-taxonomic modification often corresponding to taxonomic c h a r a c t e r i s t i c s defining other species or v a r i e t i e s already known. Gerrath (1983) looked at the morphological variation and radiation of St. pentacerum (Wolle) Smith, i t s v a r i e t i e s tetracerum (Wolle) Smith and hexacerum Irenee-Marie, and St.  sublonqipes G.M. Smith. A l l of these taxa were found to d i f f e r only in radiation, and the presence of dichotypical c e l l s with the two semicells of d i f f e r e n t radiations, prompted him to emend the description of St. pentacerum to include a l l the above named taxa. Morphological variation of other genera of desmids 1 9 in the f i e l d has also been observed (Ruzicka, 1966; Tyler, 1970; Bicudo and Sormus, 1972; Gerrath, 1979a, b, 1982). Morphological v a r i a t i o n of desmids was observed in cultures grown under d i f f e r e n t environmental conditions (Rosenberg, 1940, 1944; K a l l i o , 1953; Lorch, 1978; Watanabe, 1979). Brandham and Godward (1965) showed that with a clone of Staurastrum  polymorphum Brebisson, high temperature favored the t r i r a d i a t e specimens. Brandham and Godward (1964) examined the genetics of the occurrence of b i - and t r i r a d i a t e c e l l s in Cosmarium botrytis Meneghini and bot r y t i s var. tumidum Wolle and found that the t r i r a d i a t e state was not determined ge n e t i c a l l y . Their conclusion was strengthened by Tews' (1969) investigation of the inheritance of radiation in a clone of Cosmar ium b o t r y t i s var. depressum W. et G.S. West. Lehtonen (1977) summarized the morphogenesis studies done on Micrasterias. He suggested that morphogenesis was not determined genetically, but was plasmatically controlled. Cook (1963) studied the vegetative and sexual morphology of 18 clones of Closterium of the C.  venus-dianae complex and concluded that morphology of the conjugation tube and zygote was more stable than vegetative morphology. The need for using clonal material in combination with f i e l d material was stressed by d i f f e r e n t authors. Forster (1967) studied both morphological observations of f i e l d and culture material of St. pingue T e i l i n g . He observed that in cultured material, the processes were stouter and shorter. Naef et a l . (1978) studied the variation in morphology, mostly in 20 radiation, of Staurastrum clones from Lake Geneva cultured in the laboratory and also d i r e c t l y in the f i e l d , with both l i g h t and SEM microscopes. They concluded that the lake has three species of t r i r a d i a t e Staurastrum instead of the one species, St. g r a c i l e Ralfs previously recorded: St. cingulum (W. et G.S. West) G.M. Smith, St. sebaldi var. ornatum f. planctonicum (Lutkemuller) T e i l i n g and St. messikommeri f. planctica Thomasson. In the same paper, Bourrelly described a new forma, St. sebaldi var. ornatum f. quadribrachiata Bourrelly for a tetraradiate form which comprised only 0.3% of the t r i r a d i a t e c e l l s in culture. Their in v i t r o cultures have stouter and smaller c e l l s than the cultures in the lake. Mix (1965) examined the morphological variation of Micrasterias  swainei Hastings and Staurastrum leptocladum Nordstedt in f i e l d material and clonal culture. Her study of the former showed i t is synonymous with radiosa Agardh var. extensa Prescott et Scott. Her cultures of St. leptocladum formed Cosmar ium-1 ike c e l l s which could produce normal St. leptocladum c e l l s by c e l l d i v i s i o n . Mix stressed the importance of studying both f i e l d and clonal material. 21 D. GOALS OF THE PRESENT STUDY The present study i s concerned p r i m a r i l y with documenting and a n a l y s i n g morphological v a r i a t i o n with regard to the sys t e m a t i c s of Staurastrum and Staurodesmus. The study i n c l u d e s both f i e l d m a t e r i a l and c l o n a l c u l t u r e s observed over a p e r i o d of two and a h a l f y e ars. Comparison of p u b l i s h e d d e s c r i p t i o n s and i l l u s t r a t i o n s with the m a t e r i a l observed i s used to examine the taxonomy of the s p e c i e s . Physico-chemical analyses and i d e n t i f i c a t i o n of dominant algae growing with Staurastrum and Staurodesmus spp. are used to c h a r a c t e r i z e the h a b i t a t s . C o l l e c t i o n s i t e s are i n the lower F r a s e r V a l l e y , B r i t i s h Columbia, to the east of Vancouver. Attempts to induce sexual r e p r o d u c t i o n are undertaken to provide f u r t h e r g e n e t i c and morph o l o g i c a l i n f o r m a t i o n regarding v a r i a b i l i t y . In a d d i t i o n , an in depth study of the growth rate and morphological v a r i a t i o n of one clone i s c a r r i e d out using d i f f e r e n t media in d i f f e r e n t environmental c o n d i t i o n s . 22 11. STUDY AREAS Most s i t e s v i s i t e d were located in the Lower Fraser Valley of B r i t i s h Columbia (Fig. 2B). The main c o l l e c t i n g s i t e s of this study were Jacobs Lake (also known as Marion Lake, see Efford 1967) in Maple Ridge, and Munday, Lost and Como Lakes in Coquitlam (Fig. 2C and D). A mean annual temperature of 9.8°C and mean annual precipitations of approximately 150 cm (Kendrew and Kerr 1955) characterize the area which is part of the Coastal Western Hemlock Zone (Krajina 1969). Stein and Gerrath (1968) and Stein (1975) have studied the al g a l f l o r a of the area. Stein and Borden (unpublished) have produced a computer print-out showing the fresh-water algae recorded in B r i t i s h Columbia and their c o l l e c t i o n s i t e s . A preliminary ch e c k l i s t was published (Stein and Borden 1979) without however stating the actual s i t e s of c o l l e c t i o n of each alga. A. JACOBS LAKE Jacobs Lake (also c a l l e d Marion Lake) i s located in the UBC Research Forest in Maple Ridge, B r i t i s h Columbia (49° 18'N, 122° 33' W), about 50 km east of Vancouver (Fig. 2C). It is situated on the southern slope of the Coast Mountains which are composed of g r a n i t i c bedrock of mesozoic o r i g i n , and rests in a valley about 300 m above sea level (Efford 1967). The UBC Research Forest i s accessible to the public only by foot; Jacobs Lake is located a few km from the entrance and i s thus rarely v i s i t e d . On 25 January 1980 as well as on 11 January 1981, Jacobs Lake was covered with a thin layer of ice which was e a s i l y broken. 23 T h e UBC R e s e a r c h F o r e s t h a s b e e n t h e s i t e o f e x t e n s i v e l o g g i n g a n d r e f o r e s t a t i o n . M u c h o f t h e s e c o n d a r y g r o w t h i s c o m p o s e d o f w e s t e r n h e m l o c k ( T s u g a h e t e r o p h y l l a ( R a f . ) S a r g . ) , w e s t e r n r e d c e d a r ( T h u j a p i i c a t a D o n n . ) ( E f f o r d 1 9 6 7 ) a n d s o m e D o u g l a s f i r ( P s e u d o t s u q a m e n z i e n s i i ( M i r b e l ) F r a n c o ( W a l i e t a l . 1 9 7 2 ) . K l i n k a ( 1 9 7 6 ) d i d a s y n e c o l o g i c a l s t u d y o f t h e v e g e t a t i o n o f t h e UBC R e s e a r c h F o r e s t . M a t h e w e s ( 1 9 7 3 ) s t u d i e d t h e p o s t g l a c i a l c h a n g e s i n v e g e t a t i o n f r o m s e d i m e n t c o r e s c o l l e c t e d i n J a c o b s a n d S u r p r i s e L a k e s , b o t h l o c a t e d i n t h e U B C R e s e a r c h F o r e s t . T h e m a i n a q u a t i c v a s c u l a r p l a n t s w e r e P o t a m o g e t o n n a t a n s L . , P_^  e p i h y d r u s R a f . , N u p h a r p o l y s e p h a l u m E n g e l m . , M e n y a n t h e s t r i f o l i a t a a n d I s o e t e s o c c i d e n t a l i s H e n d e r s . , a n d t h e a l g a C h a r a g l o b u l a r i s T h u i l l . w a s a l s o r e p o r t e d a r o u n d s o m e s p r i n g s ( E f f o r d 1 9 6 7 ) . I n a d d i t i o n , t h e p r e s e n c e o f U t r i c u l a r i a s p . w a s n o t e d a t t h e s a m p l i n g s t a t i o n o n t h e w e s t s i d e o f t h e l a k e ( F i g . 2 C ) . K a l m i a s p . a n d L y s i c h i t u m  a m e r i c a n u m H u l t e n e t S t . J o h n w e r e c o m m o n o n t h e s h o r e . M a t h e w e s ( 1 9 7 6 ) s t u d i e d t h e s e d i m e n t o f J a c o b s a n d S u r p r i s e L a k e s , b o t h i n t h e R e s e a r c h F o r e s t . J a c o b s L a k e h a s a d r a i n a g e a r e a o f a b o u t 6 . 5 k m 2 a n d f l o w s i n t o t h e N o r t h A l o u e t t e R i v e r . I t i s a b o u t 8 0 0 m l o n g a n d 2 0 0 m w i d e a t i t s l a r g e s t p o i n t . A t h i g h w a t e r , t h e m a x i m u m d e p t h i s a b o u t 7 m b u t v a r i e s u s u a l l y a r o u n d 5 . 5 a n d 6 m, a n d t h e m e a n d e p t h i s 2 . 4 m ( E f f o r d 1 9 6 7 ) . A t t h e s a m p l i n g s t a t i o n , w a t e r l e v e l v a r i e d f r o m 1 . 1 7 t o 1 . 8 9 m. A m o r p h o m e t r i c map o f J a c o b s L a k e c a n b e f o u n d i n a n y o f t h e f o l l o w i n g p u b l i c a t i o n s ( D a v i e s 1 9 7 0 , E f f o r d 1 9 6 7 , D i c k m a n a n d E f f o r d 1 9 7 2 , W a l i e t a l ^ _ 1 9 7 2 ) . 24 The sampling station at Jacobs Lake was located on the western side of the lake, at the s i t e of the International B i o l o g i c a l Program (IBP) f a c i l i t i e s . Sampling for the present study was performed from and around the dock. A permanent metre stick provided a record of the variation of the lake l e v e l . Much research has been pursued on Jacobs Lake in the course of the IBP. Davies (1970) worked on the productivity of the macrophytes; Dickman (1968), Gruendling (1971) and Hargrave (1969) looked at the structure and production of the periphyton community; Duthie and Sreenivasa (1970) examined the diatoms in a sediment core from Jacobs Lake; Gerrath (1965) and Stein and Gerrath (1968) investigated the desmid populations in Jacobs Lake and other lakes in the Coast Mountain area; Dickman (1969), Dickman and Efford (1972) and Efford (1967) worked on the production of the phytoplankton; Wali e_t a l . (1972) analysed the nutrient composition of the lake. B. MUNDAY LAKE Munday Lake is located in the municipality of Coquitlam (49° 16' N, 122° 49' W), some 20 km east of Vancouver (Fig. 2D). It l i e s about 150 m above sea l e v e l and i s part of Munday Lake Memorial Park, a municipal park for recreational a c t i v i t i e s . Despite the fact that signs at the park refer to "Mundy Lake", thi s s p e l l i n g i s incorrect. The lake empties into one major outflow at i t s southern end. Munday Lake i s surrounded by t r a i l s winding through a wooded area. Children from nearby schools use the lake as a ground for fishing or c o l l e c t i n g frogs or tadpoles. Swimming i s forbidden. 25 Around the lake, the vegetation was mostly composed of Ericaceae such as Gaultheria shallon Pursh., Ledum qroenlandicum Oeder, Vaccinium sp., Kalmia sp. Closer to the lake l i e s a terrain of soft peat deposit which also covers the bottom of the lake. In some places, much care must be exercised as the ground w i l l not support the weight of a person. At d i f f e r e n t locations along the shore, populations of Sphagnum sp. may be found. The main aquatic vascular plants were Brasenia schreberi Gmel. at the southern end, some Nuphar sp. and several patches of Potamogeton sp. The lake sometimes freezes over for a few weeks during winter time. This happened in 1979-80 when the ice was ca. 2 cm thick, but in 1980-81, ice was observed only close to the shore. At Munday Lake, water samples and other physico-chemical data were co l l e c t e d from the dock located on the west side of the lake. This permitted sampling in deeper areas and minimized disturbing the fine peat sediment on the bottom of the lake. Wailes (1930, 1931) published some accounts on algae and other f l o r a and fauna found in and around Munday Lake. Donaldson (1981) and Donaldson and Stein (1984) studied the Mallomonadaceae (Synuraceae) as well as general physico-chemical aspects of the lake. 26 C. LOST LAKE Lost Lake i s also located in Munday Lake Memorial Park about 0.8 km east of Munday Lake and at the same elevation (Fig. 2D). The southern end of the lake is bordered by a t r a i l and on the west side, a wooded path runs north about half the length of the lake. Lost Lake i s not as heavily frequented as Munday Lake. At i t s southeast end, the lake drains into a man-made outflow. Lost Lake contains some peat but not as much as Munday Lake; the bottom is largely composed of mud and sand. Patches of Nuphar sp. and Potamogeton sp. were observed at the southern and northern ends of the lake. The lake froze over during the 1979-80 winter season forming a surface of ice ca. 2 cm thick, but not during 1980-81. The southern t i p of Lost Lake is lined by a tree trunk. Water samples were coll e c t e d from the trunk or by walking into the lake to a depth of 0.5-0.6 m, ca. 1-2 m from the shore. In doing so, much care was taken not to disturb the sediment. Very l i t t l e work has been done on Lost Lake. Gerrath (1965) recorded 38 desmid species from Lost Lake; there were six species of Staurastrum. D. COMO LAKE Como Lake is located about 2 km west of Munday Lake Memorial Park. It is a recreational lake encircled by one t r a i l and surrounded by grass and houses (Fig. 2D). It i s stocked with f i s h for the exclusive use of senior c i t i z e n s and children. 27 A population of ducks has established permanent residence on the lake. A major outflow located at the southern extremity of the lake often dries out at least partly during the summer. Several small inflows are dispersed around the lake. The bottom and shore of the lake are composed of mud and sand. During the summer months, large mats of Brasenia shreberi and Nymphaea odorata A i t . covered about one t h i r d of the lake. On the north side grew a large population of Typha l a t i f o l i a L. At Como Lake, a dock on the eastern side of the lake provided a sampling s i t e . Wailes (1929) established a l i s t of algae found in one sample co l l e c t e d at Como Lake. Donaldson (1981) and Donaldson and Stein (1984) made some general physico-chemical observations in the course of their study on Mallomonadaceae (Synuraceae) in Como Lake. E. OTHER SITES More than 20 other s i t e s , lakes, ponds or ditches in the Lower Fraser Valley, Okanagan Valley, Vancouver Island and the Gulf Islands ( B r i t i s h Columbia) were sampled. A l l the samples co l l e c t e d were examined for the presence of Staurastrum species. At 17 s i t e s , physical and occasionally chemical data were gathered (Table 2). Two lakes were v i s i t e d in the Okanagan Valley (Central B r i t i s h Columbia), Skaha Lake (119° 30' N, 49° 25' W) and Okanagan Lake (119° 25' N, 49° 45' W). The Coquitlam (122° 47' N, 49° 16' W) and the P i t t Rivers (122° 40' N, 49° 15' W) which both flow into the Fraser River were also sampled. Blaney, 28 Pla c i d , Gwendoline, Eunice and Katherine Lakes are a l l located in the UBC Research Forest (Fig. 2C). As previously mentioned, Gwendoline, Eunice and Katherine Lakes drain into Jacobs Lake and from there into the North Alouette River. Placid Lake also flows into the North Alouette River through Blaney Lake and Blaney Creek. Mike Lake, located in Golden Ears Provincial Park, drains into the South Alouette River (Fig. 2C). The North Alouette River was sampled where i t crosses 232 nd street in Maple Ridge. Whonnock Lake, which was studied by Donaldson (1981) and Donaldson and Stein (1984) for i t s Chrysophyceae i s located some 9 km southeast of the UBC Research Forest. Trout Lake i s located on the eastern outskirt of the c i t y of Vancouver in a recreational park and Beaver Lake i s in Stanley Park. Camosun Bog i s found in the southeastern part of the UBC Endowment Lands and J. K. Henry Lake is in the UBC Botanical Garden (Native Garden) on the southern side of the UBC campus. 29 Figure 2 - Location of sampling s i t e s in the Lower Fraser Valley A. B r i t i s h Columbia; B. Area of sampling in the lower Fraser Valley; C. Main sampling s i t e s and other lakes occasionally v i s i t e d in the UBC Research Forest and Golden Ears Provincial Park; D. Lakes in Coquitlam area. Dots in Figures C and D indicate sampling stations. Scale for C and D, 1:50,000 and B, 1:25,000. 2 9 A T A B L E - 2 S U P P L E M E N T A R Y C O L L E C T I N G S I T E S A N D P H Y a l C O - C H E M I C A L D A T A ( D . 0 . = D I S S O L V E D O X Y G E N ) Site Date pH Temperature Alkalinity Calcium D.O. ' P O 4 - 3 N03" samp-led °c mg.l CaC03 mg.l - 1 mg.l 1 ag.l- 1 mg.1-1 Beaver Lake 5-IV-80 5.7t> 19.5 . Blaney Lake 14 -VI-79 4.40 18.8 10 •*VTII -79 6.95 22.0 8.6: 4.3 5.87 16 -V-8G 6.45 12.5 3.2 2-7 10.87 8-VIII-80 5.60 19.5 3.7 3.1 8.69 28 -VIII-81 6.30 19.0 Camosun bog 18 -IV-81 4.15 12.0 - — Coquitlam River 7-VI-79 5.90 10.0 Eunice Lake 10 -VTII-79 6.55 24.0 3.9 2.9 7.22 Pond beside Eunice 10 -VIII-79 6.65 26.5 Gwendoline Lake 14 -VI-79 6.35 17.5 10 -VIII-79 23.5 2.8' 4.1 6.54 J. K. Henry Lake 13 -IV-80 5.85 10.0 24 -VII-81 4.85 16.0 Katherine Lake 10--VIII-79 6.50 23.0 3.5' 1.7 6.88 Mike Lake 15' -VIII-79 6.20 — 22--VIII-79 6.35 23.0 10.4 4.1 6.88 12--IX-79 4.90 15.5 7.8: 4.1 8.35 .05 undetectable 30' -IX-79 . 4.65 15.0 9.3 4.4 8.01 .06 undetectable 28--XII-79 6.00 1.0 North Alouette R. 1-: XT-79 6.95 7.0 Okanagan Lake 23 -VI-79 8.10 18.0 P i t t River 7-VI-79 7.45 14.5 Site Date pH sampled Placid Lake 14-VI-79 4.40 10-VTII-79 6.50 16-V-80 6.10 8-VIII-80 5.75 28- VIII-81 5.70 Skaha Lake 23-VI-79 8.20 Trout Lake l-VIII-79 7.90 29- VIII-79 8.35 Whonnock Lake 28-VI-79 6.15 29-VTII-79 6.15 5-IX-79 5.40 TABLE 2 (cont'd) Temperature Alkalinity Calcium . D.O °C mg.l"1CaCOr, mg.l"1 mg.l" 17.5 — — - — 21.5 5.7 3.5 5.6 12.5 1.4 2.3 10.6 19.0 2.7 3.4 9.0 19.5 23.0 22.0 20.1 8.3 5.5 24.0 15.1 6.9 6.1 24.0 22.0 1.4 2.2 4.7 32 I I I . MATERIALS AND METHODS A. FIELD PROCEDURES In 1979, from 16 May to 30 September, three main s i t e s were sampled usually once a week: Jacobs Lake in the UBC Research Forest, Munday and Como Lakes in Coquitlam. In 1980 and 1981 the three main lakes, as well as Lost Lake in Coquitlam, were again sampled regularly. They were v i s i t e d every four weeks from 25 January to 23 March, and every three weeks thereafter. Sampling ended on 28 August 1981. Actual sampling dates for each of the four major sampling s i t e s are given in Appendix A. 1. PHYSICO-CHEMICAL FACTORS Samples and data for physico-chemical analyses were col l e c t e d at one station in each lake (Fig. 2C, D). Samples and measurements were taken ca. 3 cm below the surface of the water unless indicated otherwise. A l l samples for chemical analyses were transported to the laboratory in an ice chest and warmed to room temperature before analysis. Before use, a l l containers and glassware for chemical determinations were soaked for 24 h in 50% HC1 or Decon detergent followed by 24 h in d i s t i l l e d water and two thorough d i s t i l l e d water rinses. These dishes were used exclusively for chemical analyses and after each analysis, they were soaked again for 24 h in d i l u t e Decon followed by a 24 h rinse in d i s t i l l e d water. A l l a n a l y t i c a l chemical solutions were kept for a maximum of one year. 33 a. PH A Markson model 85 f i e l d pH meter with precision to the second decimal was used. Calibration was accomplished with a commercial buffer solution at pH 4.00 and 7.00. On the few occasions when the f i e l d pH meter was out of order, pH was recorded immediately upon return to the laboratory with a Corning pH meter (model 125). b. Temperature A mercury thermometer graduated to the nearest degree C was held ca. 3 cm below the surface for a few minutes before taking a temperature reading. The time of recording for a given lake was f a i r l y constant, however the di f f e r e n t lakes were not v i s i t e d at the same time of the day and this may have influenced surface temperature. Sampling time varied from early morning for Jacobs Lake, to late morning for Munday and Lost Lakes and early afternoon for Como Lake. c. Light Light readings were recorded occasionally with an underwater quantum sensor (model LI-185A and Li-l92S, Licor Ltd.) in the a i r , ca. 1-2 m above the water and in the water, ca. 1 cm below the surface, at 0.5 m and at the bottom when depth permitted. A conversion factor of 1.34 was used to calculate the underwater readings as suggested by the manufacturer. 34 d. Dissolved Oxygen Samples for dissolved • oxygen were co l l e c t e d in B.O.D. bottles lowered v e r t i c a l l y , and capped under water after a l l a i r bubbles had escaped. They were p a r t i a l l y fixed in the f i e l d with manganese sulfate and a l k a l i - i o d i d e solutions. Upon return to the laboratory, sulphuric acid was added to the samples and they were either immediately analysed or stored at 5°C for a maximum of 24 h from c o l l e c t i o n time before analysis. The Winkler procedure for dissolved oxygen with azide modification was used (APHA 1975). Only one sample was analysed for each lake and sampling date. e. A l k a l i n i ty A l k a l i n i t y samples were co l l e c t e d in Pyrex or polyethylene bottles and 200 ml of each sample was analysed, when possible upon return to the laboratory, or stored at 5°C and t i t r a t e d within 24 h according to the potentiometric method (APHA 1975). A Corning pH meter (model 125), with precision to the second decimal was used. Only one sample was analysed for each lake and sampling date. Because of the low a l k a l i n i t y of Jacobs, Munday and Lost Lakes, end points of pH 4.50 and 4.20 were used (APHA 1975). The end point used for Como Lake was 4.80 since the a l k a l i n i t y was above 10 mg.l" 1 CaC0 3. 35 f. Calc ium Samples for calcium were co l l e c t e d in polyethylene bottles and analysed by the EDTA t i t r i m e t r i c method (APHA 1975) with Calcon as indicator. Two determinations were taken and an average was calculated. Periodic standardization of the EDTA t i t r a n t was conducted (APHA 1975). g. Nitrate And Phosphate For n i t r a t e and phosphate analyses, ca. 250 ml of lake water were f i l t e r e d on Whatman GF/C q u a l i t a t i v e glass fiber f i l t e r s previously washed in d i s t i l l e d water. The f i l t r a t i o n was done d i r e c t l y in the f i e l d using mouth suction or immediately upon return to the laboratory with a mechanical pump at a maximum pressure of 7 kg.cm"2 and the samples were frozen at -10°C. During the 1979 sampling season, the samples were frozen in b o r o s i l i c a t e Erlenmeyer flasks to avoid possible loss of nutrients, mostly phosphate, to polyethylene bottles. This practice was discontinued in the f a l l of 1979, because the flasks tended to break i f transferred d i r e c t l y from -10°C to room temperature. The samples c o l l e c t e d in 1979 were analysed for nitra t e with a Technicon AutoAnalyser. The nitra t e method was that of Armstrong e_t a l . (1967). It was automated for the Technicon AutoAnalyser by the method of Hager et a l . (1968). Subsequent samples were analysed manually with a cadmium reduction column (Strickland and Parsons 1972, Stainton et a l . 1977). A few n i t r i t e determinations were performed following Stainton et a l . 36 (1977). Phosphate was analysed by the ascorbic acid method (Stainton et a l 1977, APHA 1975). The samples were not processed further after f i l t r a t i o n , and the phosphate fraction analysed represents t h e o r e t i c a l l y the dissolved orthophosphate present in the samples. Only one determination was usually made for n i t r a t e and phosphate respectively, for each sampling s i t e and date. Spectrophotometric readings were taken on an Unicam SP1800 spectrophotometer. For N03~, a wavelength of 543 nm and 1 or 4 cm c e l l s were used, depending on the concentration. The li g h t path length recommended was 1 cm for a N03~ concentration of 2-20 M g . l " 1 and 5 cm for a concentration of 2-6 M g . l " 1 . The nitr a t e precision level was 120 M g . l " 1 (Stainton et a l • 1977). A wavelength of 850 nm and 4 cm c e l l s were used for phosphate determinations. The li m i t of detection was 10 M g . l " 1 for a 5 cm spectrophotometric c e l l at 880 nm (APHA 1975). A curve of absorbency vs. standard concentration was established with a series of standards and further determinations always included at least one standard. D i s t i l l e d water was used as a blank and absorbency values of untreated samples and of d i s t i l l e d water with reagents were substracted from the processed sample readings. Phosphate is easily adsorbed by the walls of storage or an a l y t i c a l containers or glassware (Murphy and Riley 1956, Thayer 1970) and for this reason a l l dishes used for phosphate analysis were thoroughly washed in a phosphate-free detergent and kept exclusively for phosphate determination. 3 7 2 . A L G A L C O L L E C T I O N T E C H N I Q U E S a . P l a n k t o n S a m p l e s P l a n k t o n t o w s a t e a c h l a k e w e r e d o n e f r o m t h e s h o r e a s d e s c r i b e d f o r e a c h l a k e . A 6 4 urn m e s h n e t w a s d r a w n c a . 10 c m u n d e r n e a t h t h e s u r f a c e o f t h e w a t e r . T h i s p r o c e d u r e w a s r e p e a t e d c a . f i v e t i m e s u n t i l a b o u t 1 2 5 m l o f s a m p l e w e r e c o l l e c t e d i n a s m a l l p o l y e t h y l e n e b o t t l e . T h e s a m p l e s w e r e c a r r i e d i n a n i c e c h e s t t o t h e l a b o r a t o r y w h e r e 1 5 - 2 0 m l w e r e p r e s e r v e d w i t h a s o l u t i o n o f L u g o l ' s i o d i n e c o n t a i n i n g a c e t i c a c i d a n d f o r m a l d e h y d e . T h e r e m a i n i n g p o r t i o n s o f t h e s a m p l e s w e r e k e p t i n g l a s s j a r s u n d e r c o o l - w h i t e f l u o r e s c e n t l i g h t i n g a t 5 o r 1 0 ° C f o r 1 - 3 0 d a y s , a w a i t i n g f u r t h e r o b s e r v a t i o n o r f o r p o s s i b l e f o r m a t i o n o r g e r m i n a t i o n o f z y g o s p o r e s . S o i l , p e a t a n d w a t e r ( S P W ) m e d i u m w a s s o m e t i m e s a d d e d . b . P e r i p h y t o n S a m p l e s L e a v e s a n d s t e m s o f a q u a t i c v a s c u l a r p l a n t s s u c h a s B r a s e n i a , N u p h a r , N y m p h a e a , P o t a m o g e t o n o r U t r i c u l a r i a w e r e s c r a p e d w i t h a c l e a n k n i f e o r s p a t u l a . S p h a g n u m o r o t h e r m o s s e s a n d f i l a m e n t o u s a l g a e w e r e s q u e e z e d t o e x t r a c t t h e w a t e r a n d a l g a e p r e s e n t . T h e s a m p l e s w e r e s t o r e d o r p r e s e r v e d s i m i l a r l y t o t h e p l a n k t o n s a m p l e s . 38 c. Sediment Samples Two types of sediment samples were co l l e c t e d in an attempt to obtain zygospores. A 1 cm diameter p l a s t i c tube was used to suck up the surface sediment and overlying water which were then transferred to a small glass v i a l , observed and preserved. Samples of sediment from moist or dry areas around the lakes were scooped up with a spatula and l e f t to dry at room temperature in paper bags. d. Preservation Of Specimens V i a l s containing preserved material from f i e l d c o l l e c t i o n s and dried sediment samples in paper bags are kept in the Department of Botany, University of B r i t i s h Columbia. B. LABORATORY PROCEDURES 1. ALGAL CULTURING The routine medium (SPW of Gerrath 1968) was made from ca. 25 ml of a s o i l obtained from the UBC Botany Department greenhouse f a c i l i t i e s , 25 ml of dried and pulverized Sphagnum (collected at Jacobs and Munday Lakes) and 1 1 d i s t i l l e d water. This mixture was autoclaved for 45 min, decanted, f i l t e r e d onto 5.5 cm q u a l i t a t i v e glass fiber f i l t e r s , poured in 100 x 20 mm test tubes and reautoclaved for 15 min. Soil-water medium (SW) was used for a few experiments and was prepared according to Nichols (1973) by steaming a mixture of 50 ml of greenhouse s o i l and 1 1 of d i s t i l l e d water for three periods of 60 min. Waris medium was prepared according to Starr 39 (1978). When used as a medium, lake water was f i r s t f i l t e r e d on 5.5 cm GF/C glass fiber f i l t e r s followed by a period of 45 min of autoclaving or three 60 min periods of steaming. Table 3 gives the n i t r a t e , phosphate and calcium content and the pH of the four media used. For a l l media except Waris, analyses were the same as for the f i e l d samples. For Waris medium, the amount of calcium, phosphate and ni t r a t e were computed from molecular weights and the quantities given in the recipe (Starr 1978). 2. ALGAL ISOLATION Upon return to the laboratory, 20 ml of each alg a l sample were transferred to the bottom of a p e t r i dish (15 x 100 mm) and examined with a dissecting microscope at a magnification of '24-100 times. Individual c e l l s were isolated using a c a p i l l a r y pipet as described in Hoshaw and Rosowski (1973). This magnification was too low to recognize the species isolated and only very s t r i k i n g c h a r a c t e r i s t i c s , such as the long and slender appendages of St. pentacerum (Wolle) G.M. Smith, could be distinguished. More subtle differences were very d i f f i c u l t to assess and wall ornamentation completely impossible. The c e l l s were washed by transferring them four or five times (Pringsheim 1946) in a few drops of s t e r i l e s o i l , peat and water medium (SPW) and placed in a well s l i d e with 1 cm depressions resting in a p e t r i dish. The dishes were then set up in a 20°C chamber on a 14:10 or 16:8 L:D cycle. The i r r a d i a t i o n was about 45 ME.m_2.s"1 provided by two cool-white fluorescent tubes at a 40 distance of 14 cm from the shelf. S t e r i l e SPW was added to the depressions as necessary. After ca. two weeks, the spot plates were examined using a dissecting microscope and the c e l l s which had divided, were picked up with a c a p i l l a r y pipet and transferred to a 100 x 20 mm test tube of s t e r i l e SPW. Each clone was assigned a number (HC #x; see Appendix C). A clone by d e f i n i t i o n , i s a culture obtained by the d i v i s i o n of a single c e l l . Culture tubes were routinely kept suspended on metal bars in a 20°C culture chamber at an i r r a d i a t i o n of 27 to 43 ME.m^.s"1 and a 16:8 L:D cycle. Growth experiments I conducted showed these conditions to be optimal for St. inflexum Brebisson (clone HC 18). Every four to six weeks, an inoculum of each culture was tranferred to a culture tube containing fresh s t e r i l e SPW medium. 3. SEXUALITY EXPERIMENTS Sexual reproduction was attempted on two he t e r o t h a l l i c clones of Staurastrum gladiosum Turner from the University of Texas at Austin, culture c o l l e c t i o n (UTEX, LB1568, LB1569) and one homothallic clone of Cosmar ium botryt i s Meneghini from Carolina B i o l o g i c a l Supply Co. (#2140; Burlington, North Carolina). Eighty-four clonal isolates of Staurastrum were subsequently tested in environmental conditions similar to the one used with the two sets of controls (see Table 6 in Results and Discussion). One clone of Closter ium 1 i t t o r a l e Gay (HC 243) was also used. The clones were tested for homothally or heterothally. Homothally arises when c e l l s of the same clone 41 conjugate with each other; heterothally means that c e l l s of one clone do not conjugate with each other but conjugate with the c e l l s of another clone. Starr's C0 2 enrichment method, which i s considered standard, was used (Starr 1955). The bottom of a deep p e t r i dish was covered with a 5% solution of NaHC03. A watch glass was set in the p e t r i dish, on a glass triangle which was i t s e l f resting on the bottom of a deep p e t r i dish. This was covered with the top of the p e t r i dish. One to two mm3 of the strain(s) to be tested were pipetted into each watch glass. The pe t r i dishes were covered and incubated. Variations based on successful techniques used by other workers (Table 7 in Results and Discussion) were t r i e d . Irradiation was between 20 and 77 ME.m^.s"1 provided by cool-white or gro-lux fluorescent tubes. The photoperiod was either 14:10, 16:8 or 18:6 L:D and the temperature was 16 to 25°C. Como Lake water, SPW and SW media, and Waris medium with d i f f e r e n t concentrations of nitrate were tested. The age of the cultures varied from a few days to over two months. Old cultures were sometimes d i l u t e d with fresh medium at the start of the experiment. Samples of mud col l e c t e d along the shore of the lakes and ponds containing populations of Staurastrum or Staurodesmus were dried at room temperature for at least one month. They were then wet with either s t e r i l e d i s t i l l e d water or SPW medium and observed every week for four to eight weeks, in an attempt to obtain zygote germination and thus isolate sexual clones. 42 4. GROWTH EXPERIMENTS Experiments on the rate of growth were performed with St. inflexum (clone HC 18). Time l i m i t a t i o n precluded using more than one clone for these experiments. Clone HC 18 was chosen because i t grew well in clonal culture and the species was common in Como Lake. Culturing was carried out in 500 ml Erlenmeyer fl a s k s . When sampled, every 1-3 days, each culture was thoroughly shaken. Factor k (divisions/day) was calculated for the exponential growth period (G u i l l a r d 1973). One experiment tested d i f f e r e n t media: Waris, f i l t e r e d Como Lake water col l e c t e d on 7 June 1980, SW, SPW, enriched SPW to which vitamin B 1 2 (0.45 M g . l " 1 ) and 1 ml of a trace metal solution were added. The i n i t i a l c e l l concentration was 513 c e l l s . m l " 1 . The i r r a d i a t i o n was 40 ME.m~ 2.s" 1 on a 14:10 L:D cycle at 16°C. A second experiment tested the growth rate in SPW at four i r r a d i a t i o n s : 12.5, 25, 42 and 90 ME.m" 2.s" 1. The temperature was 20°C and the photoperiod 14:10 L:D cycle with an i n i t i a l c e l l concentration of 3.7 x 103 c e l l s . m l " 1 . The growth rate was determined from c e l l counts using a Sedgewick-Rafter c e l l . Three chi-square analyses were performed to test for randomness d i s t r i b u t i o n of the Staurastrum c e l l s throughout the Sedgewick-Raf ter c e l l (Lund et a_l. 1958). Two of those accepted the randomness hypothesis (P=0.05) and one rejected i t . At least 400 c e l l s were counted in t r i p l i c a t e Sedgewick-Rafter c e l l s . This minimum was determined in accordance with Woelkerling et a l . (1974) and Lund et_ a l . 43 (1958) to get an accuracy of ± 10%. A t h i r d experiment used SPW medium and f i l t e r e d water from Como Lake (collected 1 February 1981) with an i n i t i a l concentration of 35 x 103 c e l l s . m l " 1 , to test i f the larger inoculum would reduce the long lag phase previously observed in SPW but not in f i l t e r e d Como Lake water. The growth rate was followed by spectrophotometric readings at 565 nm (Trainor and Schubert 1973) every two days, and c e l l counts ca. every 10 days. The temperature was 20° C, the i r r a d i a t i o n 40 ME.m"2.s_1 and the L:D cycle 14:10. Como Lake water, c o l l e c t e d on 17 May 1981, was enriched with a modified Waris medium to give the ni t r a t e , phosphate and calcium outlined in Table 3 for enriched Como Lake water (ECW). Three 500 ml Erlenmeyer flasks were set up at a temperature of 20°C, a L:D cycle of 14:10 with an i r r a d i a t i o n of 45 ME.m~2.s"1. The stock culture was one month old and the i n i t i a l c e l l concentration was 8 x 103 c e l l s . m l " 1 . After 24 days, when the cultures reached a plateau, aliquots were taken and diluted to the i n i t i a l c e l l concentration, in Erlenmeyer flasks of enriched Como Lake water from which the phosphate portion of the enrichment solution was omitted and others from which the nit r a t e portion was missing. T r i p l i c a t e samples were set up for each treatment. The resulting nutrient shock may have been useful for the study of sexual reproduction. 44 5. ICONOTHEQUE Nordstedt (1896, 1908) has been used extensively to locate the names and o r i g i n a l references of v a r i e t i e s , forms and species which were isolated in culture. For taxa published since then, however, a personal b i b l i o g r a p h i c a l search was necessary. An Iconotheque containing o r i g i n a l descriptions and i l l u s t r a t i o n s as well as subsequent published figures of Staurastrum taxa has been compiled. Some 350 publications are included in the album, a l i s t of which is given in Appendix B. Origin a l publications of taxa which were only c i t e d in other papers l i s t e d in the Iconotheque are not included. It must be noted however, that especially for long publications obtained through the i n t e r l i b r a r y loan service of the Woodward l i b r a r y (UBC), often only part of the publication was ordered. This means that the Iconotheque does not include a l l published records of Staurastrum and Staurodesmus published in the references of Appendix B. The Iconotheque includes some 800 species, v a r i e t i e s and forms. Preserved f i e l d material from samples was i d e n t i f i e d using mainly West and West (1912), West et a l . (1923) and Irenee-Marie (1939), but also i f necessary, the Iconotheque compiled. 4 5 6 . M O R P H O L O G I C A L V A R I A T I O N M o r p h o l o g i c a l v a r i a t i o n w a s s t u d i e d b y s e v e r a l t e c h n i q u e s . A L e i t z c o m p o u n d m i c r o s c o p e w i t h c a m e r a l u c i d a a t t a c h m e n t , a n i n t e r f e r e n c e c o n t r a s t L e i t z m i c r o s c o p e w i t h p h o t o g r a p h i c a t t a c h m e n t , a n d C a m b r i d g e 2A a n d 2 5 0 T S E M w e r e u s e d . F o r S EM o b s e r v a t i o n s , c e l l s w e r e p r o c e s s e d t h r o u g h c r i t i c a l p o i n t d r y i n g ( C P D ) f o l l o w i n g t h e m e t h o d o f P i c k e t t - H e a p s ( 1 9 7 3 ) w i t h m i n o r m o d i f i c a t i o n s . T h e c e l l s w e r e f i r s t l o a d e d o n a p r e f o l d e d p o l y c a r b o n a t e N u c l e o p o r e f i l t e r h e l d i n a M i l l i p o r e p l a s t i c f i l t e r h o l d e r u s i n g a 5 c c s y r i n g e . T h e f i l t e r w a s t h e n r e m o v e d f r o m t h e h o l d e r , r e f o l d e d a n d p l a c e d f o r 1 . 5 h a t r o o m t e m p e r a t u r e i n a v i a l c o n t a i n i n g a 2% s o l u t i o n o f 0-g l u c u r o n i d a s e ( P i c k e t t - H e a p s 1 9 7 3 ) m a d e u p w i t h t h e g r o w t h m e d i u m ; i t w a s t h e n r i n s e d i n c u l t u r e m e d i u m f o r 1 . 5 h a n d w a s f i x e d i n 1% OsO„ s o l u t i o n f o r 1 h f o l l o w e d b y d e h y d r a t i o n i n a s e r i e s o f e t h a n o l s o l u t i o n s o f i n c r e a s i n g c o n c e n t r a t i o n a n d i n a m y l a c e t a t e , p l a c e d i n a s m a l l s t a i n l e s s s t e e l b a s k e t a n d p r o c e s s e d t h r o u g h C P D i n a C 0 2 b o m b . I n e a r l y p r e p a r a t i o n s , e a c h s t u b w a s c o a t e d w i t h c o l l o i d a l g r a p h i t e a n d t h e c e l l s w e r e p i c k e d u p d i r e c t l y b y p r e s s i n g t h e s t u b v e r y g e n t l y o n t h e o p e n e d f i l t e r p o u c h . H o w e v e r l o n g p r o c e s s e s o r s p i n e s w e r e o f t e n d a m a g e d o r b e n t . T h e t e c h n i q u e w a s t h u s m o d i f i e d a s f o l l o w s : t h e p r o c e s s e d f i l t e r w a s f i x e d t o a s t u b w i t h a s i l v e r c o n d u c t i n g p a i n t , t r i m m e d , a n d t h e s t u b s w e r e h e a v i l y c o a t e d w i t h g o l d i n a v a c u u m e v a p o r a t o r a n d o b s e r v e d w i t h t h e S E M . T h e S E M u s e d i n t h e f i r s t y e a r w a s a C a m b r i d g e m o d e l 2A b u t s u b s e q u e n t o b s e r v a t i o n s w e r e p e r f o r m e d w i t h a C a m b r i d g e m o d e l 46 250T. EFKE KB17 120 mm films from Fotokemika (Yugoslavia) were used for SEM photography and were developed in Rodinal or occasionally in Edwal developer. Panatomic-X fi l m (Kodak) was used for l i g h t microscope photography and processed in Edwal developer. In the investigation of variation of clone HC 18, twenty-five c e l l s were measured in each t r i p l i c a t e set-up for each environmental condition (medium, i r r a d i a t i o n , temperature, pH). Culturing was carried out in culture tubes suspended on metal bars. The conditions tested were based on the standard culturing methods in use at UBC (see following) and l i t e r a t u r e reports. Each experiment lasted 30 days. An analysis of variance (Snedecor and Cochran 1967) was used to detect s i g n i f i c a n t differences due to the conditions tested. The test for difference between variances of two independent samples (Bruning and Kintz 1977) was used to evaluate the homogeneity of the variances, since proportions were analysed ( L / l ra t i o and percentage). No s i g n i f i c a n t difference between the variances was revealed and thus the data were not transformed. Standard deviation was calculated. SW, SPW, Como Lake water, ECW, Sand SPW and Steamed SPW media were tested for rate of growth (T= 20°C; Irradiation= 45 ME.m~2.s~1; 16:8 L:D cy c l e ) . The f i r s t four media were described e a r l i e r . In the Sand SPW medium, the s o i l f r a c t i o n was cut in half by an equal amount of sand, while the Steamed SPW medium was steamed according to the method described by 47 Nichols (1973). Irradiations of 75, 42 and 25 M E . H T 2 . S ~ 1 were tested on cultures in SPW medium at a temperature of 20°C, a 16:8 L:D cycle and a pH of 4.62. The effects of temperature (5, 10 and 20°C) were examined (Irradiation=45 ME.nr 2.s~ 1; 16:8 L:D cycle; pH= 4.62). Cultures in SPW medium (pH= 4.62) and in SPW medium to which CaC03 was added (pH= 6.20) were tested at 20°C, an i r r a d i a t i o n of 45 /uE.m^.s"1 and a 16:8 L:D cycle. In the course of a Youth Employment Program project, Pauline Monck (unpublished) c u l t i v a t e d clone HC 18 in a biomonitor (Schlichting 1975) in the f i e l d and in the laboratory. For the f i e l d experiment, the biomonitor was placed at a depth of ca. 0.5 m in J.K. Henry Lake, in the UBC Botanical Garden (Native Garden). The laboratory biomonitors were placed in aquaria f i l l e d with either Munday Lake water, J.K. Henry Lake water, or SPW medium. Th i r t y - f i v e c e l l s (based on the result of a running mean calculated on four d i f f e r e n t samples) of each i s o l a t e investigated for morphological variation were measured using the li g h t microscope. Standard deviation and c o e f f i c i e n t of variation were calculated for each clone. The standard conditions used were a temperature of 20°C, a L:D cycle of 16:8 and an i r r a d i a t i o n of ca. 40 ME.m~2.s~1. Radiation was counted on at least 100 c e l l s . The basic terminology used to describe Staurastrum and Staurodesmus has -been i l l u s t r a t e d in Figure 1 (p. 8). Abbreviations chosen for dimensions are derived from Irenee-Marie (1939) who used abbreviations derived from L a t i n : 48 L = le n g t h L(cp) = le n g t h with processes L(sp) = le n g t h without processes 1 = width l ( c p ) = width with processes l ( s p ) = width without processes l ( c s p ) = width with spines l ( s s p ) = width without spines Sp = le n g t h of spines Pr = Length of processes Is = width of isthmus. The e x p r e s s i o n L / l r a t i o r e f e r s to the l e n g t h with processes or spines (unless otherwise mentioned), d i v i d e d by the width with processes or s p i n e s . For each taxon the o r i g i n a l d e s c r i p t i o n i s quoted. When re f e r e n c e i s made in the t e x t to a P l a t e or F i g u r e provided in t h i s study, the l e t t e r P or F i s always c a p i t a l i s e d . References to i l l u s t r a t i o n s by other authors are i n small p r i n t . Drawing P l a t e s are a l p h a b e t i c a l l y numbered ( P l a t e s A-R) and are i n c l u d e d in Appendix D. Photographic P l a t e s ( P l a t e s 1 - 1 8 ) as w e l l as r a d i a t i o n and measurement Tables (Tables 11-30) are i n numerical order and are found a f t e r the corresponding taxon. 49 T A B L E 3 N U T R I E N T CONTENT OF M E D I A USED FOR GROWTH E X P E R I M E N T S Med i u m NO?:,I mg.l J P 0 4 m g . l - 3 - 1 C a l c i u m m g . l - 1 p H F i l t e r e d Como L a k e w a t e r (7 J u n e 1 9 8 0 ) 0 . 1 0 0 . 0 3 1 1 . 4 6 . 7 5 F i l t e r e d Como L a k e w a t e r ( 1 F e b r u a r y 1 9 8 1 ) 0 . 5 3 u n d e t e c t a b l e 1 0 . 4 6 . 7 0 F i l t e r e d Como L a k e w a t e r ( 1 7 M a y 1 9 8 1 ) 0 . 0 4 u n d e t e c t a b l e 1 0 . 6 5 . 6 0 E n r i c h e d Como L a k e w a t e r (ECW) 0 . 3 1 (17 May 1 9 8 1 ) 0 . 0 6 6 2 . 0 SW ( N i c h o l s 1 9 7 3 , p . 2 2 ) * 0 . 9 3 1 . 6 6 SPW ( G e r r a t h 1 9 6 8 ) " 0 . 9 8 1 . 4 9 4 5 . 3 4 . 6 2 W a r i s ( S t a r r 1 9 7 8 ) @ 1 8 . 5 0 4 . 6 9 1 4 . 7 6 . 0 0 * A v e r a g e o f v a l u e s f r o m f i v e p r e p a r a t i o n s ( C o e f f i c i e n t o f v a r i a t i o n = 8 .8%) + A v e r a g e o f v a l u e s f r o m e i g h t p r e p a r a t i o n s ( C o e f f i c i e n t o f v a r i a t i o n = 11 . 2%) @ C a l c u l a t e d v a l u e s 50 IV. RESULTS AND DISCUSSION A. PHYSICO-CHEMICAL FACTORS Physico-chemical factors for the main sampling s i t e s are plotted in Figures 3-6. The scale used for each lake may vary. Irradiation measurements are given in Table 4. pH values were lower at Munday and Lost Lakes; that is generally between 4.00 and 5.00 with values up to 6.75 during summer 1979. Values at Jacobs Lake ranged between 4.85 and 6.50, and at Como Lake, between 5.60 and 7.20. Low pH has been often associated with the presence of desmids in lakes. Moss (1973) found that desmids considered to be oligotrophic did not grow at pH over 8.6. He related his results to the u n a v a i l a b i l i t y of free C0 2 as a carbon source for photosynthesis at t h i s pH. The lakes studied here are low in the nutrients analysed and are oligotrophic or dystrophic (Ruttner 1967). The lakes froze during winter 1979-1980 but not during 1980-81. Maximum temperatures recorded in July were 26°C for Jacobs and Munday and 27°C for Lost and Como Lakes. Jacobs Lake was usually a few degrees cooler than the other lakes and the quickest to freeze during the winter due to i t s higher elevation and more i n t e r i o r location. Desmids were rare during winter and most abundant from spring to f a l l . Croasdale (1957, 1965, 1973) has found a r i c h desmid f l o r a in the A r c t i c . Duthie (1964) demonstrated that i f desmids are subjected to an acclimation period at 4°C, they w i l l survive freezing well. The scarce desmid population present during the winter and at low 51 temperature in laboratory experiments, show that the f i e l d and clonal populations in this study did not grow well at temperatures below ca. 10°C. A l k a l i n i t y was highest at Como Lake, that i s between 18 and 33 mg.l" 1 CaC0 3. At Jacobs Lake, i t varied between 4.85 and 6.75 mg.l" 1 CaC0 3. Munday and Lost Lakes showed a l k a l i n i t y from 0 to 6.3 mg.l" 1 CaC0 3, which was not surprising because of their low pH. For the four lakes, a l k a l i n i t y was in general highest during the summer months (Fig. 3-6). Brook (1959b) related le v e l s of a l k a l i n i t y to the occurrence of d i f f e r e n t species of desmids. The ranges of a l k a l i n i t y given were usually large enough to include a l l four main sampling lakes in the present study. Kovask (1973) established a p a r a l l e l between desmid taxa and the bicarbonate (HC03") content of lakes. He grouped the algae according to the type of lake in which they were found. Two sub-groups are of interest here: one with 0-10 mg.l" 1 HC03" and a second with 10-60 mg.l" 1 HC03". Few species were endemic to one sub-group. Among them, St. inconspicuum belonged to the f i r s t sub-group and was found in Jacobs Lake (Table 5); St.  brebi ssoni i , St. furc igerum, St. furcigerum f. eustephanum and St. tetracerum which were in the second sub-group, were found in lakes of very low a l k a l i n i t y (Jacobs, Munday and Lost Lakes; Table 5). As expected from the higher a l k a l i n i t y , calcium was two to three times higher at Como Lake than at the three other s i t e s and varied between 8.3 and 11.8 mg.l" 1 CaC0 3. At Jacobs, Munday and Lost Lakes, i t ranged between 1.8 and 5.9 mg.l" 1 CaC0 3. No 52 seasonal trend c o u l d be d e t e c t e d . Desmids have o f t e n been c h a r a c t e r i z e d as c a l c i p h o b i c , although other r e l a t e d f a c t o r s such as the a v a i l a b i l i t y of f r e e C0 2 or the t o t a l mineral content now appear s i g n i f i c a n t . Experiments by Tassigny (1971) showed that the growth of many n o n - o l i g o t r o p h i c desmids was not a f f e c t e d by calcium l e v e l , although o l i g o t r o p h i c s p e c i e s grew more slowly as c a l c i u m c o n c e n t r a t i o n i n c r e a s e d . Values fo r d i s s o l v e d oxygen (D.O.) v a r i e d between 4.8 and 11.2 mg.l" 1 at Munday and Lost Lakes, with some i n c r e a s e during summer and a d e c l i n e i n the f a l l . Values fo r Como Lake v a r i e d between 3.3 and 14.7 mg.l" 1 and f o r Jacobs Lake, between 5.6 and 13.9 mg.l" 1. The range of v a r i a t i o n f o r the four lakes was s i m i l a r . N i t r a t e content at Munday and Lost Lakes was much higher than at Como and Jacobs Lakes, with maximum values reaching more than 1' mg.l" 1 d u r i n g winter and e a r l y s p r i n g , with a decrease d u r i n g the summer and an i n c r e a s e i n the f a l l . Except f o r a few h i g h v a l u e s i n winter and s p r i n g of 1980, n i t r a t e was g e n e r a l l y low at Como Lake, with l i t t l e seasonal v a r i a t i o n ; i t ranged between a low of 8 M g . l " 1 and a maximum value of 820 M g . l " 1 on 23 February 1980. Values at Jacobs Lake were always low and v a r i e d between 8 and 80 M g . l - 1 . R e s u l t s of a n a l y s e s of f i v e s e t s of samples from the four main lakes showed that no n i t r i t e was present i n any of the lakes sampled. Phosphate analyses p r i m a r i l y showed that phosphate l e v e l s in a l l l a k e s were very low and o f t e n at the l i m i t of d e t e c t i o n . The h i g h e s t value (50 M g . l " 1 ) recorded was at Munday Lake on 23 53 February 1980. A l l lakes showed undetectable levels of phosphate (see following) during the f a l l and winter of 1980-81 and at the end of the 1981 summer. Some of these samples were analysed upon return to the laboratory before freezing, but the results were unchanged. In 1980, a series of four samples were analysed upon return to the laboratory and then after a period of 4.5 months, during which the samples were frozen at -10°C in order to measure the possible loss of phosphate to the polyethylene bottles. No loss was detected. This suggests that losses during freezing were not responsible for the low phosphate level observed. In general, phosphate values in 1979 and the f i r s t half of 1980 were higher than in 1981. Contamination of glassware may have been partly responsible for these higher values, and repeated washings in Decon over time may have removed a l l the residual phosphate present on the walls of the glassware. Phosphate is ea s i l y adsorbed by the walls of glassware as previously noted in the Material and Methods. The ascorbic acid method used is r e l a t i v e l y s e n s i t i v e ; i t s l i m i t of detection being 10 Mg.l" 1 for a 5 cm spectrophotometric c e l l at 880 nm (APHA 1975). Donaldson reported high values with e r r a t i c variations in Munday and Como lakes for 1978 (up to ca. 6 and 11 mg.l - 1 respectively), while in 1979, values were below 1 x 103 mg.l" 1 (Donaldson 1981). Armstrong (pers. comm.) used glassware cleaned with strong acid and Wetzel and Likens' (1979) method for low phosphate concentration. He found that concentration of orthophosphate in Como Lake was in the order of 10 Mg.l" 1 or 54 l e s s . Studies on the e f fec ts of n i t r a t e and phosphate concentrations on desmids have not been reported in the 1 i te rature . 55 F i g u r e 3 - Phys i co-chemica l data fo r Jacobs Lake (n=see M a t e r i a l s and Methods ) . A. pH ( ) and temperature ( ); B. D i s s o l v e d oxygen ( ), a l k a l i n i t y ( ) and c a l c i u m ( ) ; C. N 0 3 _ ( ) and P 0 „ - 3 { ) 55A 56 F i g u r e 4 - Phys i co-chemica l data fo r Munday Lake (n=see M a t e r i a l s and Methods) A. pH(- ) and temperature { ); B. D i s s o l v e d oxygen ( ), a l k a l i n i t y ( ) and c a l c i u m ( •.••); C. N 0 3 " ( ) and P O « ' 3 ( -) 56A 1980 1 9 8 1 57 F i g u r e 5 - Phys i co-chemica l da ta fo r Lost Lake (n=see M a t e r i a l s and Methods) A. pH ( ) and temperature ( ). B. D i s s o l v e d oxygen ( ), a l k a l i n i t y ( ) and c a l c i u m ( ); C. N 0 3 " { ) and P 0 „ - 3 ( ) 57A 58 F i g u r e 6 - Phys i co-chemica l data fo r Como Lake (n=see M a t e r i a l s and Methods) A. pH ( ) and temperature (" ). B. D i s s o l v e d oxygen ( ), a l k a l i n i t y (• ) and c a l c i u m ( ); C. N 0 3 " ( ) and PO<,"3 ( ) 5 8 A Date Jacobs Lake a i r water 0.01 m 0.5 m 1980 7-VT 115 0 804 27-VI 235 174 18-VII 1110 750 30-VII 720 723 19 81' 22-11 600 335 13-111 85 27 7-IV 345 241 17-V 700 630 9-VT 660 603 30-VT 145 125 88 22-VTI 290 235 11-VIII 120 67 43 28-VIII 780 871 670 TABLE 4 IRRADIATION MEASUREMENTS Lost Lake a i r water . 0.01 m 0.5 m 1170 1000 :235 234 1500 1206 1725 1407 850 871 350 281 2000 2010 1057 150 125 52 100 94 43 600 630 268 1300 1333 402 (uE.m - 2^- 1) Munday Lake a i r water 0.01 m 0.5 m 1950 1849 235 187 705 603 1650 1547 190 255 550 361 228 1010 871 509 220 168 105 730 402 395 900 871 603 900 670 416 Como Lake a i r water 0.01 m 0.5 m 1800 1380 215 148 1800 1809 480 375 500 349 22 8 + 100 87 47 120 134 67 830 697 469 1500 1340 1005 840 670 375 @ * 0.175 m - 47; 0.325 m = 23 + 1.0 m - 161 @ 0.75 m = 188 60 B. DISTRIBUTION OF ALGAL GENERA IN LAKES STUDIED Algae other than Staurastrum and Staurodesmus were generally i d e n t i f i e d only to genera. A brief overview of the lakes according to their phycological components and their r e l a t i v e seasonal abundance follows. 1. JACOBS LAKE Phytoplankton in samples from Jacobs Lake was scarce. The samples were coll e c t e d from the dock in a r e l a t i v e l y shallow area and the top part of the loose sediment was sometimes disturbed; thus desmids as well as diatoms l i v i n g on the sediment were occasionally found in plankton samples. Tetmemorus granulatus (Brebisson) Ralfs or T a b e l l a r i a fenestrata (Lyngb.) Kiitzing which were also abundant on the sediment at some times of the year were found in the plankton. The only other taxon found in abundance was Dinobryon, on 10 August 1979. Although i t is not usually considered as periphytic, i t was also found in some amount among the periphyton c o l l e c t e d on the same date. Periphyton samples including e p i p e l i c and epiphytic samples were richer in algae, p a r t i c u l a r l y in desmids and diatoms. Water containing microscopic algae was col l e c t e d after squeezing plants of U t r i c u l a r i a or filaments of Zygnemataceae. These plants were found in early spring and supported a good desmid growth. Desmids were abundant from early March through late September; the peak season for Staurastrum spp. was July and 61 August. Tetmemorus qranulatus proved to be a very abundant and an often dominant periphytic alga during the summer months. Tetmemorus, Penium and Closterium were the only desmid genera present in any great abundance, although a large number of genera (19) were recorded. Staurodesmus was rare. From late September through to the middle of March, pennate diatoms were the most abundant algae. Around the end of May and the beginning of June, Ta b e l l a r i a fenestrata and T . flocculosa (Roth) Kiitzing were dominant. The only member of the Cyanophyceae was O s c i l l a t o r i a seen on 11 October 1980. On a few occasions, c e l l s of the genera Cryptomonas, Ceratium and Peridinium were seen. Synura was observed on one occasion and Dinobryon was the dominant alga on 10 August 1979 as previously mentioned. 2. MUNDAY LAKE Phytoplankton was also quite rare in samples from Munday Lake. Plankton samples were coll e c t e d from a dock; periphytic species originating from the loose sediment were occasionally found in them. Among the species which can be considered as tru l y planktonic, K i r c h n e r i e l l a contorta (Schmidle) Bohlinand Peridinium were r e l a t i v e l y abundant in June. Tabellaria  fenestrata and T\_ flocculosa were common in September. Colonies of Dinobryon were p a r t i c u l a r l y abundant from February to A p r i l . Staurastrum pentacerum was found mainly in the plankton from the end of June through early August 1980; some c e l l s 62 persisted up to the end of October. In 1979 and 1981, only a few individuals of this species were recorded. Periphyton samples were obtained from squeezings of Sphagnum sp. or algae growing among dead aquatic plants attached to the sediment on the shores of the lake. . Desmid genera were r e l a t i v e l y fewer than at Jacobs Lake; only 10 genera were i d e n t i f i e d . Desmids were most abundant from spring to f a l l . One species of Staurastrum, St. muricatum, was found in abundance among Sphagnum populations during that period. Staurodesmus was not common. Tabellar ia f enestrata and T_^  f locculosa were dominant during August and September and other pennate diatoms were common on the sediment. The green algae were represented by Bulbochaete, Oedogonium and Klebsormidium and were found among decaying roots of higher plants or on the peat mats in August and September. Peridinium was abundant in the periphyton samples in June and July and was probably mostly of planktonic o r i g i n . Cyanophyceae, Chrysophyceae and Cryptophyceae were occasionally recorded. Two species of Euglena formed a green growth on the peat mat beside the dock and were p a r t i c u l a r l y noticeable during the month of August. 63 3. LOST LAKE Lost Lake has an al g a l composition similar to that of Munday Lake, although usually with fewer individuals. The fact that aquatic vascular plants and mosses were less common may well account for this difference. The most abundant genera in the plankton were Synura, Dinobryon and to some extent, Cryptomonas and Peridinium. Synura was p a r t i c u l a r l y abundant in samples col l e c t e d in March and September 1980 and again in A p r i l 1981 . Desmid genera were similar to those in Munday Lake with the exception of one occurrence of Spirotaenia in Lost Lake. Species of Staurastrum were similar to the species found at Munday Lake. St. pentacerum was found only occasionally and St. muricatum Brebisson was less common than in Munday Lake. Staurodesmus was rare. Among diatoms, the genera T a b e l l a r i a and Melos i ra were most common during the spring and the f a l l . Many genera of pennate diatoms were commonly found on the sediment or among other plants, as in the other lakes studied. Peridinium was abundant in a sample c o l l e c t e d on 12 September 1979. During summer time, two species of Euqlena formed green patches on the shore of the lake, just above water l e v e l . A few other Euglenophyceae were occasionally recorded. Members of the Cyanophyceae and Cryptophyceae were very rarely observed. 64 4. COMO LAKE Como Lake had the r i c h e s t a l g a l growth of the four main c o l l e c t i n g s i t e s , mostly in the p l a n k t o n . Seasonal dominance i n the plankton was assumed by d i f f e r e n t s p e c i e s . P e r i d i n i u m sp. dominated the plankton i n s p r i n g and f a l l and Ceratium  h i r u n d i n e l l a (O.F. M i i l l e r ) D u j a r d i n was a l s o abundant at t h i s t ime. Dinobryon spp. were very abundant in s p r i n g and f a l l . Synura and Mallomonas were a l s o w e l l represented members of the Chrysophyceae d u r i n g the c o o l e r months of the year. A s t e r i o n e l l a formosa Hass. and T a b e l l a r i a spp. bloomed around the same time, with T\ f e n e s t r a t a and T\_ f l o c c u l o s a mainly of p e r i p h y t i c o r i g i n . Many genera of algae were found growing among aqu a t i c p l a n t s . Only seven genera of desmids were recorded but a few s p e c i e s of Staurodesmus and Staurastrum were present in high numbers from s p r i n g to the end of the summer. They occurred under the l e a f blades and on the stems of Nymphaea and on decomposing p l a n t s of B r a s e n i a , among f i l a m e n t s of S p i r o g y r a , and were a l s o found on the sediment. Mougeot i a was abundant mostly around February whereas S p i r o g y r a was more important from A p r i l through the end of the summer. Fi l a m e n t s of Oedogonium and Bulbochaete were a l s o common. Bulbochaete was found growing a t t a c h e d to the t i r e s s u p p o r t i n g the dock. A number of genera of C h l o r o c o c c a l e s were found among a q u a t i c v a s c u l a r p l a n t s . Some f r e e l i v i n g c o c c o i d Xanthophyceae were a l s o observed. 6 5 M a n y p e n n a t e d i a t o m s l i v e d a m o n g t h e r o o t e d v e g e t a t i o n . T a b e l l a r i a f e n e s t r a t a a n d T ^ f l o c c u l o s a w e r e a g a i n t h e d o m i n a n t d i a t o m s d u r i n g s p r i n g a n d f a l l . I n a s a m p l e c o l l e c t e d o n 2 2 F e b r u a r y 1 9 8 1 , b o t h T a b e l l a r i a a n d A s t e r i o n e l l a f o r m o s a w e r e a b u n d a n t . D i n o b r y o n , S y n u r a a n d M a l l o m o n a s w e r e a l s o r e c o r d e d i n p e r i p h y t o n s a m p l e s a s w e r e P e r i d i n i u m a n d C e r a t i u m h i r u n d i n e l l a . T h e s e w e r e m o s t l i k e l y f r o m p l a n k t o n i c o r i g i n . C y a n o p h y c e a e w e r e r e p r e s e n t e d b y a n u m b e r o f g e n e r a . C r y p t o m o n a s a n d E u g l e n a w e r e r e l a t i v e l y c o m m o n . A n o u t f l o w a t t h e s o u t h e n d o f t h e l a k e w a s s a m p l e d a f e w t i m e s . A r o u n d t h e e n d o f F e b r u a r y , i t s h o w e d a h e a v y g r o w t h o f D r a p a r n a l d i a p l u m o s a ( V a u c h . ) A g . s u p p o r t i n g a v a r i e t y o f s m a l l p e n n a t e d i a t o m s a n d s o m e C h l o r o c o c c a l e s . D r a p a r n a l d i a w a s r e p l a c e d b y S p i r o g y r a d u r i n g t h e s p r i n g a n d s u m m e r w i t h m a n y s p e c i e s o f S t a u r a s t r u m a n d S t a u r o d e s m u s i n t e r m i n g l e d w i t h t h e S p i r o g y r a f i l a m e n t s . O t h e r r e p r e s e n t a t i v e s o f t h e m o s t a b u n d a n t a l g a e i n t h e l a k e s u c h a s P e r i d i n i u m , D i n o b r y o n , a n d T a b e l l a r i a , a l s o o c c u r r e d a m o n g t h e S p i r o g y r a f i l a m e n t s . 5 . O T H E R S I T E S M i k e L a k e i n G o l d e n E a r s P r o v i n c i a l P a r k w a s v i s i t e d o n f i v e o c c a s i o n s i n 1 9 7 9 . S i m i l a r l y t o J a c o b s L a k e , p l a n k t o n s a m p l e s c o n t a i n e d f e w a l g a e . P e r i p h y t o n s a m p l e s y i e l d e d 1 4 g e n e r a a n d n u m e r o u s s p e c i e s o f d e s m i d s , a m o n g w h i c h w e r e S t a u r a s t r u m a n d S t a u r o d e s m u s . F i l a m e n t o u s C h l o r o p h y c e a e , e s p e c i a l l y Z y g n e m a a n d S p i r o g y r a , w e r e a b u n d a n t i n A u g u s t . 66 Small pennate diatoms were common as were Ta b e l l a r i a fenestrata and Melosira. Euqlena formed isolated green patches on the wet mud around the lake. Other algae observed included Peridinium, Ceratium, Dinobryon, Synura, Mallomonas, Oedoqonium, species of Chlorococcales, filamentous and coccoid Cyanophyceae. Beside Mike Lake l i e s an unnamed pond which was sampled on 15 August 1979. It was similar to Mike Lake in i t s alg a l composition. The two most abundant algae were T^ fenestrata and Bambusina, which was not recorded in Mike Lake. A number of other desmid genera were also recorded including Staurastrum and Staurodesmus. A series of lakes in the UBC Research Forest were v i s i t e d on d i f f e r e n t occasions (Fig. 2C). Placid Lake was v i s i t e d f i v e times. Nine desmid genera were recorded, including Staurastrum and Staurodesmus, as well as Spi rogyra, Dinobryon, Euglena, Ceratium and genera of Chlorococcales, diatoms and Cyanophyceae. Five v i s i t s to Blaney Lake yielded ten genera of desmids, including Staurastrum and Staurodesmus. The other algae recorded were similar to Placid Lake. Gwendoline Lake was v i s i t e d on two occasions in 1979. Representatives of planktonic algae were scarce and samples co l l e c t e d from moss squeezings and among Drosera revealed fiv e genera of desmids including Staurastrum, some Chlorococcales, diatoms and Cyanophyceae. Eunice Lake was sampled on 10 August 1979 but very few algae and no Staurastrum or Staurodesmus were observed. However, a pond adjacent to the lake included fiv e d i f f e r e n t 67 genera of desmids including Staurastrum, as well as Mougeotia, Scenedesmus and Anabaena. Katherine Lake, v i s i t e d on the same day, showed a predominance of Dinobryon in i t s plankton. Five genera of desmids were recorded including Staurastrum and Staurodesmus, as well as filaments of Mougeot ia and Zyqnema, some Cyanophyceae and Dinophyceae The South and North Alouette Rivers were sampled at their intersection with 232nd street in Maple Ridge, on 10 August and 1 September 1979, and 23 March 1980. Rock scrapings and sediment samples provided a number of species of Cosmarium, Closterium and Cosmarium-like Staurastrum l i v i n g among Spiroqyra filaments. Pennate diatoms, some of which were growing in tubes, were abundant. Whonnock Lake was sampled on three occasions in 1979 (28 June, 29 July, 5 September). Eleven genera of desmids were recorded, however neither Staurastrum nor Staurodesmus were abundant. Peridinium was dominant on 28 June 1979 in the plankton. Genera of Chlorophyceae, Cryptophyceae, Euglenophyceae and Bacillariophyceae were also recorded. A plankton tow was made in the P i t t River on 7 June 1979 just beside the P i t t River bridge. It contained mostly the species Asterionella formosa with some Dinobryon. The Coquitlam River was sampled on the same date, beside the Coquitlam bridge. The only desmid found was Closterium. Dinobryon, Audouinella, Draparnaldia plumosa and d i f f e r e n t genera of diatoms were observed. 68 Trout Lake was v i s i t e d on four occasions (18 September, 1978, 27 May, 2, 29 August 1979). The lake supported a very r i c h plankton growth. Four genera of desmids were recorded, among which were Staurastrum and Staurodesmus. The dominant alga on 27 May 1979 was Anabaena; Melosira, Dinobryon and Pediastrum simplex (Meyen) Lemmermann were also quite abundant. J. K. Henry Lake located in the UBC Botanical Garden (Native Garden) close to 16th Avenue was v i s i t e d on four occasions in 1979 and 1980 (25 May 1979, 18 A p r i l , 30 May, 30 July 1980). In summer 1981, i t was the s i t e for a study conducted by Pauline Monck (unpublished) and referred to in Chapter 3 section B.6 and Chapter 4, section F.1. J.K. Henry Lake contained 16 genera of desmids and many individuals mostly of the filamentous desmids, although not many species of Staurastrum and Staurodesmus were seen. Many c e l l s of Tabellar ia and other pennate diatoms were present in the spring. Filamentous green algae, p a r t i c u l a r l y the Zygnemataceae, were also abundant and species of the Chlorococcales were common. Peridinium, Cryptomonas, Dinobryon, Synura and a few genera of Cyanophyceae were also observed. A c o l l e c t i o n t r i p around Stanley Park on 5 A p r i l 1980 provided a large amount of Closterium 1 i t t o r a l e Gay from a ditch not far from the Stanley Park zoo. Other lakes, ponds and ditches were sampled on Vancouver Island, the Gulf Islands, the Okanagan Valley and the lower mainland but were not of any par t i c u l a r interest for the study of Staurastrum or Staurodesmus. 69 One sample was c o l l e c t e d on 28 July 1980 from a pond in the VanDusen Botanical Garden in Vancouver. Spiroqyra was the main alga in that sample but Staurastrum proboscideum (Ralfs) Archer f. i minor (Schmidle) Prescott, Bicudo and Vinyard was also found. 70 C. DISTRIBUTION OF STAURASTRUM SPP. AND STAURODESMUS SPP. IN LAKES STUDIED Sixty-one s p e c i e s and v a r i e t i e s of Staurastrum (St. ) and Staurodesmus (Std.) were i d e n t i f i e d i n t h i s study. Nine s p e c i e s are new records f o r the p r o v i n c e , and there are 56 new d i s t r i b u t i o n records f o r s p e c i e s a l r e a d y known in the p r o v i n c e . These data are summarized i n Table 5. The i n f o r m a t i o n concerning new records are based on S t e i n and Borden (unpub l i s h e d ) . Since samples were sometimes screened with a d i s s e c t i n g microscope, or observed with a compound microscope but not i d e n t i f i e d to s p e c i e s l e v e l , not a l l the Staurastrum or Staurodesmus observed i n a l l samples were i d e n t i f i e d . T h i s e x p l a i n s the absence from Table 5 of some lakes which co n t a i n e d a few Staurastrum or Staurodesmus s p e c i e s but which were not i d e n t i f i e d . T h i s l i s t i s not an exhaustive c o l l a t i o n of a l l the s p e c i e s present i n the lakes sampled. The taxonomic treatment of the m a t e r i a l was very c o n s e r v a t i v e . Numerous taxa of Staurastrum and Staurodesmus have been d e s c r i b e d on only minor and unstable v a r i a t i o n s and represent a major problem to taxonomists who have to decide on the v a l i d i t y of taxa. I t was thus c o n s i d e r e d a p r i o r i t y to f i t the specimens to known taxa, r a t h e r than d e s c r i b e new taxa on minor v a r i a t i o n s . TABLE 5 SPECIES OF STAURASTRUM (St.) AND STAURODESMUS (Std.) FROM THE LOWER FRASER VALLEY (* taxon already known to this lake; ** taxon new to this lake; *** taxon new to Bri t i s h Columbia) Species St. aculeatum (Ehrenberg) Meneghini St. alternans Brebisson ex Ralfs St. anatinum Cooke et Wills St. anatinum var. lagerheimii (Schmidle) W. et G.S. West St. anatinum var. truncatum W. West St. arachne Ralfs St. arctiscon (Ehrenberg) Lundell St. arcuatum Nordstedt St. arcuatum var. guitanense W. West St. avicula Brebisson St. boreale W. et G.S. West St. brachiatum Ralfs Jacobs Munday Lost Como ** ** * ** * *** ** *** Placid Gwendo- Mike line Trout VanDusen J.K. Garden Henry ** ** ** ** Species Jacobs St. brasiliense Nordstedt var. l u n d e l l i i W. et G.S. West St. brebissonii Archer ** St. cerastes Lundell ** St. coarctatum Brebisson ** var. subcurtum Nordstedt St. conspicuum W. et G.S. West *** St. crenulatum (Nageli) Delpoate St. cornutum Archer * St. furcatum (Ehrenberg) ** Brebisson St. furcigerum Brebisson * .St. furcigerum f. eustephanum ** (Ehrenberg) Nordstedt St. furcigerum f . armigerum (Brebisson) Nordstedt St. gladiosum Turner * St. gracile Ralfs St. gracile var. nanum Wille ** TABLE 5 (cont'd) Munday Lost Como Placid Gwendo- Mike Trout VanDusen J.K. line Garden Henry ho ** ** TABLE 5 ( c o n t ' d ) S p e c i e s Jacobs S t . g r a l l a t o r i u m N o r d s t e d t v a r . f o r c i p i g e r u m Lage rhe im * * S t . i n consp i cuum No rds t ed t * * S t . i n f l e x u m B r e b i s s o n S t . . j o h n s o n i i W. e t G .S . West * * S t . l e p t a c a n t h u m N o r d s t e d t * * S t . l e p t o c l a d u m No rds t ed t v a r . i n s i g n e W. et G . S . West S t . l o n g i r a d i a t u m W. et G . S . * * West S t . maamense A r c h e r * * S t . m a n f e l d t i i De l pon t e v a r . * * parvum Messikommer S t . ma rga r i t a ceum (Ehrenberg ) * * M e n e g h i n i S t . m i c r o n W. Wast * * * S t . mur i ca tum B r e b i s s o n S t . mut icum B r e b i s s o n * * Munday L o s t Como P l a c i d Gwendo- M i k e T r o u t VanDusen J.K. l i n e Garden Henry ** ** ** ** ** * * ** T A B L E 5 ( c o n t ' d ) S p e c i e s S t . o p h i u r a L u n d e l l * S t . o r b i c u l a r e R a l f s * S t . o r b i c u l a r e v a r . d e p r e s s u m ** R o y e t B i s s e t S t . p e n t a c e r u m ( W o l l e ) S m i t h S t . p r o b o s c i d e u m f . m i n o r * * * ( S c h m i d l e ) C o n t a n t n o v . c o m b . S t . s e b a l d i R e i n s c h * * S t . s e n a r i u m ( E h r e n b e r g ) R a l f s S t . s e t i g e r u m C I e v e S t . s e x c o s t a t u m B r e b i s s o n v a r . * * p r o d u c t u m W. W e s t S t . s i m o n y i H e i m e r l * * S t . s u b a v i c u l a W. e t G . S . W e s t * * * S t . s u b c r u c i a t u m C o o k e e t W i l l s S t . s u b n u d i b r a c h i a t u m W. e t * * * G . S . W e s t S t . t e t r a c e r u m R a l f s * S t . t o h o p e k a l i g e n s e W o l l e * J a c o b s M u n d a y L o s t Como *** *** ** *** P l a c i d G w e n d o - M i k e l i n e ** T r o u t V a n D u s e n J . K . G a r d e n H e n r y *** *** *** *** *** TABLE 5 ( c o n t ' d ) S p e c i e s J a c o b s M u n d a y L o s t S t . t o h o p e k a l i g e n s e v a r . t r i f u r c a t u m W. e t G . S . W e s t S t . v e s t i t u m R a l f s * * S t d » ^ d e . j e c t u s ( B r e b i s s o n ) T e i l i n g * * * S t d . b r e v i s p i n u s ( B r e b i s s o n ) C r o a s d a l e S t d . m a m i l l a t u s v a r . m a x i m u s (W* W e s t ) T e i l i n g :. S t d . m u c r o n a t u s v a r . d e l i c a - t u l u s ( G . S . W e s t ) T e i l i n g * * * S t d . m u c r o n a t u s v a r . s u b t r i a n - g u l a r i s $W. e t G . S . W e s t ) G r o a s d a l e Como P l a c i d G w e n d o - M i k e T r o u t V a n D u s e n J . K . l i n e G a r d e n H e n r y ** ** ** ** ** ** *** *** ** 76 D. SEXUALITY EXPERIMENTS 1. CLONES ISOLATED Among the 84 clones of Staurastrum spp. tested for sexual reproduction according to Starr's C0 2 enrichment method, none conjugated in the conditions described in Table 6. In a few instances there was an indication of pairing of c e l l s . In clones HC 2, 4 and 6 (St. proboscideum f. minor) the formation of a bulge at the isthmus was observed after six days of incubation under cool-white fluorescent tubes, but conjugation never occurred. Since conjugation did not occur with Starr's method, which is considered standard, variations based on successful techniques used by others were t r i e d without success (Table 6 and 7). No zygotes were produced in the f i e l d samples stored in the culture chambers. Mud samples which were rehydrated did not produce any desmid c e l l s but desmid zygotes were seen in two preserved samples from Jacobs Lake. However, since no c e l l s were attached to the zygotes, i t was impossible to determine to which species or genus they belonged. One homothallic clone of Closterium l i t t o r a l e Gay (HC 243) did conjugate readily in culture without the aid of the C0 2 enrichment method. The sample from which the clone was isolated was co l l e c t e d on 5 A p r i l 1980 from a ditch in Stanley Park, Vancouver. Vegetative c e l l s of CI. l i t t o r a l e were abundant. The clone seemed to produce zygospores only in cultures containing mostly dead c e l l s ; bright green cultures had few or 77 no zygospores. 2. CLONES FROM CULTURE COLLECTIONS The following experiments were performed to determine i f the experimental conditions applied to HC clones (see Appendix C) in an attempt to induce sexual reproduction would be successful with clones known to be sexual. One homothallic clone of Cosmar ium botryt i s (#2140) was tested under the conditions stated in Table 6. It produced zygotes after two days of incubation and, after six days, the cultures contained ca. 100% zygotes. Heterothallic clones of Staurastrum gladiosum (LB1568, LB1569) used by Winter and Biebel (1967) and obtained from University of Texas culture c o l l e c t i o n did not show conjugation so readily. Three d i f f e r e n t sets of conditions had to be t r i e d before obtaining zygotes (Table 6). A few zygotes were seen after 12 days in a SW medium, using Starr's C0 2 enrichment technique. Lippert (1967) mentions that after a few years in culture, clones may lose their sexual p o t e n t i a l . That could explain p a r t i a l l y the poor rate of success achieved with these clones. The s i t e s and organisms sampled in this study were not ideal for induction of sexual clones. Literature reports show that ponds or shallow areas prone to desiccation produce more sexual clones than larger bodies of water. Starr (1955) successfully isolated sexual clones from populations where there already were signs of sexual reproduction. As stressed by Coesel and Texeira (1974) and Mollenhauer (1975), success in 78 ind u c i n g c o n j u g a t i o n i s lower with the more advanced genera of desmids and many tend to abandon the process (see s e c t i o n B in I n t r o d u c t i o n ) . The sexual stage of many s p e c i e s of Staurastrum and most taxa I s t u d i e d i s unknown. Although f u r t h e r v a r i a t i o n s and combinations of environmental c o n d i t i o n s c o u l d be t r i e d , the chances of inducing c o n j u g a t i o n i n HC clones are remote. Most c o n d i t i o n s recognized as fa v o u r a b l e i n in d u c i n g sexual r e p r o d u c t i o n , as d i s c u s s e d i n the i n t r o d u c t i o n , are l a c k i n g and standard methods have f a i l e d to produce any s e x u a l i t y . Clone TABLE 6 CLONES AND ENVIRONMENTAL CONDITIONS USED FOR SEXUAL EXPERIMENTS Medium Irradiation HC 2, 4, 6, 12, 13, 18, 20, 22, 24, 25, 34, 39, 40, 41, 42, 43, 44, 45, 47, 49, 57, 58, 60, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 73, 77, 79, 97, 102, 110, 115, 119, 122, 127, 133, 150, 151, 173, 205, 210, 211, 213, 223, 272, 288, 292, 295, 296, 302, 306, 312, 318, 323, 325, 340, 368, 386, 389, 414, 418, 419, 427, 433, 435, 436, 438, 468, 469, 473, 474, 479, 490, 492, 496, 497 SPW L:D cycle Temperature (uE.m ".s"-1) (°C) Gro-lux 45 CO? enrich-ment Result 16:8 20 yes No zygotes HC 2, 4, 6, 12, 13, 18, 20, 22, 24, 25, 58, 60 SW Gro-lux 45 16:8 20 yes No zygotes TABLE 6 ( c o n t ' d ) C l o n e HC 2 , 4 , 6 , 1 3 , 18 HC 2 4 3 ( C I . l l t t o r a l e ) HC 2 , 4 , 6 , 1 3 , 1 8 M e d i u m SW SPW I r r a d i a t i o n ( u E . m . s - 1 ) SPW & C o o l - w h i t e 70 C o o l - w h i t e 2 0 - 4 0 F i l t e r e d C o o l - w h i t e C W ( 3 1 - I - 8 1 ) 45 L : D c y c l e T e m p e r a t u r e C 0 0 e n r i c h - R e s u l t m e n t 1 8 : 6 1 4 : 1 0 1 6 : 8 ( ° C ) 20 20 20 y e s no y e s N o z y g o t e s Z y g o t e s N o z y g o t e s C o . b o t r y t i s C a r o l i n a B i o . s u p p l y C o . #2140 S t . g l a d i o s u m UTEX LB 1 5 6 8 x 1 569 SPW & SW SPW & SW SPW & SW W a r i s ; N 0 ^ ^ . . 9 9 0 x 1 0 ~ 0 M > — io" JM - 3 M . 4 9 5 x . 1 9 8 x 10 . 0 9 9 x 10" SW G r o - l u x 45 C o o l - w h i t e 45 C o o l - w h i t e 77 " C o o l - w h i t e 5 0 C o o l - w h i t e 40 1 6 : 8 1 4 : 1 0 1 4 : 1 0 20 20 1 6 : 8 20 1 4 : 1 0 2 2 - 2 5 16 y e s y e s Z y g o t e s p r e s e n t a f t e r 2 d a y s C a . 100% z y g o t e s a f t e r 6 d a y s Same y e s N o z y g o t e s ; some p a i r i n g y e s N o z y g o t e s ; some p a i r i n g y e s M u c h p a i r i n g ; f e w z y g o t e s a f t e r 12 d a y s TABLE 7 Species Closterium venus-dianae Irra d i a t i o n (uE.m .s ) ca. 36 CI. l e l b l e i n l i ca. 54 CI. acerosum CI. s l l i q u a " CI. k u t z i n g i l CI. ehrenbergii Coamarium bo t r y t l s  Staurastrum polymorphum St. denticulatum CI. strigosum culture: ca. 66 conjugation: ca. 166 SUMMARY OF TECHNIQUES USED FOR DESMID CONJUGATION DIFFERENT WORKERS (Irradiation converted to uE.m .s ) L:D cycle Temperature Technique 16:8 12:12 < 9 20 20 25-27 C0 2 enrich-ment or spon-taneous in SW CO2 enrich-ment. In E.A. George medium +6% peat ext. Homo- or het e r o t h a l l i c Homothallic Onset of conjugation ,Heterothallic Honothallic N-deficient medium. C e l l concentration: 6-8 x 10 4 }Z H e t e r o t h a l l i c Age of culture Zygospore germination Reference Cook, 1963 o month old. Brandham and Dried, revet Godward, 1964 1 month Ichimura, 1971 CI. l i t t o r a l e 4-40 W fluo-rescent tubes 18:6 20 SW + 1% SW CaC0 3 agar Homothallic 3-6 wk Pickett-Heaps and Fowke, 1971 CI. moniliferum ca. 25-41 18:6 ca. 25-41 with 14:10 gro-lux tubes 14-25 Waris medium Homothallic 5-7 days 3 days Dubois-Tylski, 1973a Species CI. rostratum CI. moniliferum Irradiation (ME.m-ca. 41 witn gro-lux tubes ca. 17 with gro-lux tubes ca. 25 with gro-lux tubes L:D cycle 18:6 24:0 12:12 & 18:6 TABLE 7 (cont'd) Temperature Teclininue Homo- or Onset of heterothallic conjugation 22 Waris medium Homothallic 20 No N2 or N2 deficient Waris Homothallic 8 days Age of Zygospore Reference culture -germination Dubois-Tylski, 1973b Dubois-Tylski, 1977 CI. moniliferum conjugation: ca. 58 16:8 CI. limneticum culture: var., fallax ca. 25 Micrasterias  papillifera Co. botrytis ca. 89 with v. subfcumidum- warm-white fluorescent tubes 18:6 25 culture: 20 20-23 C02 enrich-ment in SW C02 enrich-ment in SW Homothallic Heterothallic Readily 2 days 3-5 wk Coesel and Texeira, 1974 Starr, 1955 Mi. mahabu-leshwarensis Gro-lux tubes 16:8 25 C02 enrich-ment of Des.-mid agar + soil ext. Heterothallic 2 days Blackburn and Tyler, 1980 00 St. gladiosum ca. 36 16:8 25 C02 enrich-ment in SW Heterothallic 2 days In 2-10 wk Winter and Biebel, Spontaneous 1968 after 2 months 83 E. GROWTH PATTERN OF STAURASTRUM INFLEXUM (CLONE HC 18) IN  DIFFERENT ENVIRONMENTAL CONDITIONS Experiments to measure growth rate and morphological variations were not performed at the same time, although sets of conditions were often similar (see Materials and Methods). Results of the preliminary experiment on growth rate are shown in F i g . 7. Como Lake water (7 June 1980) showed the highest factor of d i v i s i o n per day, k=0.34 (as calculated by the computation of k for the period of exponential growth; G u i l l a r d 1973), the shortest lag phase (ca. 4 days) and the shortest period of exponential growth (ca. 9 days). However, the maximum y i e l d after 26 days was 23 x 103 c e l l s . m l " 1 , which is 10 times lower than the y i e l d for the SPW medium. This result was to be expected because of the low le v e l of nitrogen and phosphorus present in Como Lake water (Table 3). Waris medium produced an irregular exponential growth curve. After 39 days, the number of c e l l s was equivalent to that found in Como Lake water. The growth in terms of divisions per day was 0.116 (Fig. 7). The other media also produced a slow exponential growth period extending over ca. 1.5 month. Computation of c e l l numbers vs. time indicated a lag phase of about two weeks which was not apparent when log of c e l l numbers were used as in Figure 7. The SW medium produced a f i n a l y i e l d of about half that for the two SPW media; that i s ca. 130 x 103 c e l l s . m l " 1 in SW and 84 250-310 X10 3 c e l l s . m l " 1 in SPW. The number of div i s i o n s per day was 0.154 for the SW medium, 0.135 for the SPW medium without additions and 0.147 for the SPW medium with addition of vitamin B,2 and trace metals. This experiment showed SPW to be a suitable medium for the culture of clone HC 18. Although the growth rate was very slow, i t followed a normal curve and gave a high number of c e l l s for observations. For general maintenance of cultures, transferring every four to six weeks thus seems adequate, as c e l l s are then transferred towards the end of their exponential growth phase. Como Lake water from 1 February 1981 (Table 3) was also tested against SPW medium. After 14 days, in both media, the number of c e l l s . m l " 1 reached 130 x 103 with k= 0.135 . The spectrophotometric readings showed that whereas the cultures in SPW medium continued to grow, the cultures in Como Lake water slowly l e v e l l e d off after day 14. The large inoculum used (see Materials and Methods) change the pattern of growth of clone HC 18 in SPW medium, but growth in Como Lake water from February was slower than in the preceding experiment with water from 7 June 1980. Table 3 shows differences between the chemical constituents analysed, but other chemicals which were not analysed may also have been responsible for the slower growth of clone HC 18. The experiment on the effect of d i f f e r e n t i r r a d i a t i o n s on growth rate used only SPW medium. This choice was prompted by the routine use made of thi s medium during the present study, and because i t yielded the highest number of c e l l s in the 85 preceding growth experiments. Results are given in Figure 8B. L i t t l e difference was seen between the 90 and 42 ME.m~ 2.s _ 1 irradiances. At 90 ME.m~2.s"1 however, the lag phase was ca. three days shorter than at 42 ME.m"2.s~1 and although both curves followed each other very clo s e l y , the culture at 90 ME.m" 2.s _ 1 was always ca. 6 X10 3 c e l l s . m l " 1 denser than the culture at 42 ME.m"2.s"1. The growth constant k was 0.108 in the f i r s t case, and 0.105 in the second. The culture at 25 ME.m" 2.s _ 1 showed a longer lag phase and somewhat irregular exponential growth phase. The number of di v i s i o n s per day was 0.105. The culture under 12.5 ME.m"2.s"1 showed no exponential growth phase and had a factor k of 0.065. In 63 days, i t increased i t s c e l l number by a factor of 16. These observations suggest that an i r r a d i a t i o n above 42 M E.nr 2.s - 1 up to at least 90 ME.m^.s"1 i s satis f a c t o r y for the growth of clone HC 18. A t h i r d experiment used Como Lake water (17 May 1981) enriched with a modified Waris solution (Fig. 8A). In addition to the n i t r a t e , phosphate and calcium concentrations given in Table 3, magnesium was present at a concentration of 6.82 mg.l" 1 and 0.5 mg.l" 1 of an iron sequestrine solution (Starr 1978) was also added. The goal of this experiment was to test i f enrichment of Como Lake water would promote the growth of clone HC 18 from Como Lake, and i f the clone would grow without N03~ or PO«" 3. The nutrient shock resulting from the omission of N03" or POft"3 (see Materials and Methods) may have been useful in experiments on sexual reproduction. However, despite the enrichment of the 86 water, the number of di v i s i o n s per day (k=0.125) was not higher than in the experiment with Como Lake water co l l e c t e d in February and described e a r l i e r . Thus i t appears that even when enriched, Como Lake water does not provide a better medium than SPW for the growth of clone HC 18 (isolated from Como Lake). When the cultures reached the end of the exponential phase after 25 days, they were dil u t e d to their o r i g i n a l number (day 0) with two d i f f e r e n t media composed of enriched Como Lake water: one from which the phosphate fractio n had been omitted, and the other from which the nit r a t e f r a c t i o n was missing. A l l three replicates of both treatments showed either no or l i t t l e growth after eight days and thus these media could not be used for sexual experiments. 87 F i g u r e 7 - Growth ra te of S tauras t rum in f l exum (c lone HC 18) in d i f f e r e n t media A. Como Lake water , 7-VI-80 (• ) and War i s medium ( ) B. SPW medium ( ), SPW medium e n r i c h e d w i th a s o l u t i o n of t r a ce meta ls and v i t am in B 1 2 (SPW+. ) and SW medium ( 4 in 40 uE. m ~ 2 . s " 1 i r r a d i a t i o n , 14:10 L :D, 16°C 87A 88 Figure 8 - Growth rate of Staurastrum inflexum (clone HC 18) in di f f e r e n t media and at d i f f e r e n t i r r a d i a t i o n s A. ECW 17-V-81, 45 j i E . m - 1 . s " l o g c e l l s . m l ' 1 ( ), absorbance ( ) B. SPW medium at 90 (•;•) , 42 ( ), 25 ( ~) or 12.5 ( —) ME.m^.s-1. T=20°C, L:D=14:10 88A 89 F. MORPHOLOGICAL VARIATION OF STAURASTRUM INFLEXUM (CLONE HC  18) IN DIFFERENT ENVIRONMENTAL CONDITIONS 1. CULTURE MEDIA Clone HC 18 was cultured in d i f f e r e n t culture media for up to 30 days. Average measurements and radiation of the c e l l s and standard deviations are given in Tables 8 and 9. An analysis of variance showed no s i g n i f i c a n t difference in the L / l r a t i o (F=4.61; P=0.05) nor the number of t r i r a d i a t e c e l l s (F=1.41; P=0.05) between the d i f f e r e n t media at 10, 20 and 30 days of c u l t u r i n g . The stock cultures used had 80-85% of t r i r a d i a t e , 10-12% of tetraradiate and 6-8% of dichotypical t r i - t e t r a r a d i a t e c e l l s . The cultures in Como Lake water, ECW (Table 3), ECW without addition of nitrogen (ECW-N) or phosphate (ECW-P) contained mostly dead c e l l s by day 30. Too few c e l l s were present in enriched Como Lake water medium after 30 days, thus no measurements were made. The cultures in Sand SPW medium showed a long lag phase; after 10 days, there were too few c e l l s and measuring was begun only a f t e r 20 days. In Pauline Monck's experiment (see Materials and Methods), a l l cultures showed a t y p i c a l batch culture (without renewal of nutrients) growth curve, with an exponential phase tapering off to a plateau. Monck believed t h i s result to be due to the biomonitor not allowing a free flow of nutrients through the membrane f i l t e r . If nutrients had been constantly replenished, 90 they should have permitted a prolonged exponential growth. Measurements of 35 c e l l s in each culture showed that the c e l l s from the f i e l d were generally wider while their isthmus was s l i g h t l y narrower. Average dimensions found by Ms. Monck were: L Kcp) Is L / l (jum) (jum) (m) F i e l d : 22 30 8 0.73 Laboratory: J.K.Henry Lake water 21 26 8 0.80 Munday Lake water 22 25 9 0.86 SPW medium 22 26 9 0.84 The most interesting results however, concern the va r i a t i o n in radiation. While the c e l l s in f i e l d culture were almost a l l t r i r a d i a t e , the c e l l s in laboratory cultures developed a pentaradiate form on which the spines were p a r t i c u l a r l y well developed. Table 9 shows that clone HC 18 was either predominantly t r i r a d i a t e or ca. half t r i r a d i a t e and half tetraradiate, and that pentaradiate c e l l s were rare. I completed the analysis on the radiation of the c e l l s in the samples co l l e c t e d by Pauline Monck (Table 10). In the laboratory cultures, the radiation passed progressively from a dominant t r i r a d i a t e form to a predominance of dichotypical c e l l s composed of one t r i r a d i a t e and one pentaradiate semicell after 27 and 20 days, followed by a predominance of pentaradiate c e l l s after 34 and 27 days respectively in J.K. Henry Lake water and SPW medium. In Munday Lake water, no sample was available for day 27 and that may explain the apparent more di r e c t t r a n s i t i o n from t r i r a d i a t e to pentaradiate dominance, without a t r i -91 pentaradiate dominant phase in between. Monck analysed the amount of phosphate and n i t r a t e present in the medium contained in the biomonitors and in the aquaria at the beginning and at the end of her experiment (ca. 40 days). She found that whereas the n i t r a t e content decreased, the phosphate content unexpectedly rose both inside and outside the biomonitors. This increase varied from four to 50 times, giving f i n a l POj,"3 concentrations in the aquaria of 11, 17 and 126 Mg.l" 1 for J.K. Henry Lake water, Munday Lake water and SPW medium respectively. The PO,"3 concentrations inside the biomonitors were 27, 6 and 130 Mg.l" 1, respectively. The concentration of calcium either increased or remained constant. The pH increased by 1.00-3.00 (between 5 and 8). Variations of pH from 4.55 to 6.00 were observed in J.K. Henry Lake and no pentaradiate c e l l s were seen (Table 10) and thus pH cannot be the only answer. The increase in P0 4~ 3 l e v e l i s also very interesting and provides another possible explanation for the observed change from a dominance of t r i - to pentaradiate c e l l s . No r e l a t i o n between phosphate and radiation has ever been shown in the l i t e r a t u r e . Changes in radiation in laboratory cultures of Staurastrum  polymorphum have been reported by Brandham and Godward (1965), in response to change in temperature, but the controlled temperature conditions used in the present study with the laboratory cultures preclude such an interpretation. Many pentaradiate c e l l s possessed two prominent spines at the base of each side of the process, s i m i l a r l y to St. incisum Wolle (1884; 92 p. 132, p i . 41 f i g . 12-14) 2. IRRADIATION Three d i f f e r e n t i r r a d i a t i o n s were t e s t e d , that i s 75, 42 and 25 ME.m~2.s~1. Measurements of the c e l l s a f t e r 10, 20 and 30 days of c u l t u r e are given i n Table 8. An a n a l y s i s of va r i a n c e on the r a t i o L / l (F=0.76, P=0.05) re v e a l e d no s i g n i f i c a n t d i f f e r e n c e s between the treatments and the time of sampling. There does not seem to be any morphological change l i n k e d with the treatments, as seen through microscope examinat i o n . More t e t r a r a d i a t e c e l l s were present than i n the experiment with the d i f f e r e n t c u l t u r e media ( s e c t i o n F.1). However, no s i g n i f i c a n t d i f f e r e n c e was found by the a n a l y s i s of va r i a n c e f o r t r i r a d i a t e c e l l s (F=0.10; P=0.05), and t h i s i s l i k e l y due to the use of a stock c u l t u r e with a higher p r o p o r t i o n of t e t r a r a d i a t e c e l l s ( ca. 68% t r i r a d i a t e , 23% t e t r a r a d i a t e and 9% t r i -t e t r a r a d i a t e ) . The r a d i a t i o n p a t t e r n stayed b a s i c a l l y the same throughout the experiment. 3. TEMPERATURE Temperatures of 15, 10 and 5°C were t e s t e d and an a n a l y s i s of v a r i a n c e f a i l e d to r e v e a l any s i g n i f i c a n t d i f f e r e n c e s i n the L / l r a t i o (F=0.86; P=0.05) nor the number of t r i r a d i a t e c e l l s (F=3.34; P=0.05) between the treatments and the time of sampling (Tables 8 and 9). R a d i a t i o n a l s o stayed unchanged throughout the experiment and the t r i r a d i a t e form was c o n s t a n t l y dominant. The stock had c a . 80% t r i r a d i a t e , 12% t e t r a r a d i a t e and 8% t r i -9 3 tetraradiate c e l l s . The percentage of the t r i r a d i a t e form was s l i g h t l y lower at 5°C with a s l i g h t l y higher percentage of tetraradiate and t r i - tetraradiate dichotypical c e l l s . This is in keeping with Brandham and Godward's (1965) experiment on radiation and temperature. An analysis of variance f a i l e d to reveal any s t a t i s t i c a l l y s i g n i f i c a n t difference. The cultures at 5°C grew very poorly. After 20 days, many of the c e l l s were dead so that counts for 20 and 30 days are based on 10 c e l l s instead of 35. 4. PH Two d i f f e r e n t pH values were tested, 4.62 and 6.20. The SPW medium had an o r i g i n a l pH of 4.62, whereas a pH of 6.20 was obtained by adding CaC03 to the SPW medium. No s i g n i f i c a n t differences were shown between treatments and sampling dates through an analysis of variance of the L / l r a t i o (F=2.68 P=0.05; Table 8). Radiation was variable, the tetraradiate form being more abundant in the cultures of pH 6.20 (Table 9). It should be noted that t h i s experiment was started with the same stock culture as for the experiment on i r r a d i a t i o n , and thus contained a higher proportion of tetradiate c e l l s o r i g i n a l l y (ca. 68% t r i r a d i a t e , 23% tetraradiate and 9% t r i - t e t r a r a d i a t e ) . However, whereas after 10 days, the proportion of t r i - to tetraradiate c e l l s was ca. 1:1 for pH 6.20, i t was of ca. 3:1 for pH 4.62. An analysis of variance showed that there was s i g n i f i c a n t difference in the number of t r i r a d i a t e c e l l s at d i f f e r e n t pH (F=44.92; P=0.05). pH was measured two days after day 30 and 94 had increased markedly in both media. In the pH 6.20 culture, the average was 8.57 and in pH 4.62, the average was 8.49. pH cannot explain the change in radiation pattern, since the f i n a l pH was the same in both sets of cultures and other media made with Como Lake water had a pH between 6.00 and 7.00. Possibly the addition of CaC03 to raise the pH to 6.20 may have played a role in the changes observed. I am not aware of any other workers noting a rel a t i o n between pH and radiation of desmids. The only other instance in the present study where a complete reversal of radiation pattern was observed is in a culture of clone HC 18 in SPW medium di l u t e d in half with d i s t i l l e d water, and grown in a 500 ml Erlenmeyer flask. After one month, the radiation percentage changed from 83.5% of t r i r a d i a t e c e l l s to 99.5% of tetraradiate c e l l s . These results agree with those of Brandham and Godward (1965), which related higher l e v e l of radiation to slow growth. In their study, however, low temperature was responsible for the slower growth. In the present study, the poorer n u t r i t i v e value of the diluted medium i s postulated as responsible for the slow growth. However, this does not explain f u l l y the changes observed because a change in radiation pattern would also have been expected in Como Lake water, ECW (Table 3) or Sand SPW media, which were r e l a t i v e l y low in nutrients and showed signs of slow growth and deterioration. TABLE 8 AVERAGE CELL DIMENSIONS OF STAURASTRUM INFLEXUM (CLONE HC 18) IH DIFFERENT ENVIRONMENTAL CONDITIONS (after 10, 20 and 30 days of culturIng; 25 cells x 3 replicates; Av= Average; I.D.= Standard deviation) Treatment L (f^ m) l(cp) (>pn) Is (flm) L / l days of growth :0 10 20 30 10 20 30 10 20 30 10 20 30 Av S.D. Av g.D. Av S.D. Av S.D. Av S.D. Av S.D. Av S.D. Av S.D. Av S.D. T=20° C; 16:8 L:D Irradiation= 45 uE. SPW 23 1.59 23 1.38 22 1.51 28 2.04 28 2.22 27 2.24 8 0.65 8 0. 57 8 0.53 0.83 0.83 0.83 SW 22 1.55 22 1.32 21 1.38 30 4.59 28 2.26 30 3.51 8 0.61 8 0. 48 8 0.49 0.73 Q.79 0.72 Como Lake water 21 1.17 20 1.69 20 1.15 25 2.68 24 2.62 25 2.74 7 0.55 7 0. 48 8 0.57 0.82 0.83 0.81 ECW 20 1.21 20 1.24 — — 25 1.86 26 1.99 — -~ 8 0.69 8 0. 55 — -- 0.80 0.78 — ECW-N 21 1.28 21 1.32 20* 1.60* 27 2.39 27 1.96 27 2.24 8 0.70 8 0. 50 8 0.45 0.80 0.78 0.75 ECW-P 22 1.26 21 1.54 21 1.17 27 2.85 27 2.60 26 2.57 8 0.68 8 0. 59 8 0.60 0.79 0.77 0.78 Steamed SPW 22 1.37 21 1.26 23 1.22 26 2.70 25 2.02 26 2.17 9 0.66 8 0. 55 8 0.63 0.89 0.85 0.87 Sand SPW — 22 1.35 21 1.33 — — 26 2.09 27 2.60 — — 8 0. 57 8 0.45 -- 0.84 0.79 SPW medium; 16:8 L:D_2 Irradiation= 45 yfi.m s ; pH= 4.62 15°C 22 1.71 22 1.85 22 1.62 26 2.22 25 2.58 26 2.62 8 0.62 8 0. 72 8 0.59 0.83 0.85 0.83 10°C 23 2.00 23- 1.40 23 1.78 27 3.92 27 3.03 26 3.04 8 0.67 8 0. 60 8 0.67 0.84 0.83 0.87 5° C 21 1.49 21 1.78 21* 1.02* 24 2.33 24 2.00 23* 1.91* 8 0.77 8 0. 84 8* 0.69* 0.89 0.89 0.89 VO Treatment days of growth SPW medium; T« 20°C; 16:8 L:D;.pH= 4.62 75 uE.m .s 42 uE.nf 2.s _ 1 o c * -2 -1 25 uE.m ,s SPW medium; T= 20°C; 16:8 L:Dj Irradiation* 45 uE.m .s pH 6.20 pH 4.62 TABLE 8 (cont'd) 10 L (um) 20 30 10 l(cp) (um) 20 30 10 Is (Hm) 20 30 10 L/l 20 30 Av S.D. Av S.D. Av S.D. Av S.D. Av S.D, Av S.D. Av S.D. Av S.D. Av S.D. 23 1.26 24 1.49 23 1.49 28 2.59 27 2.18 26 2.34 8 0.55 9 0.54 8 0.66 0.85 0.88 0.90 23 1.27 23 1.17 23 1.12 26 2.13 26 1.90 26 2.55 8 0.61 9 0.58 8 0.57 0.85 0.88 0.90 24 1.14 23 1.13 23 1.60 28 2.25 26 2.11 25 2.56 9 0.68 9 0.57 8 0.57 0.85 0.88 0.90 23 1.31 23 1.50 22 1.39 22 1.37 23 1.18 23 1.22 27 2.13 26 2.77 25 2.27 8 0.69 8 0.62 26 1.91 26 2.62 26 2.57 8 0.50 8 0.57 8 0.75 0.85 0.89 0.90 8 0.74 0.87 0.89 0.91 * 2 replicates TABLE 9 CELL RADIATION OF STAURASTRUM INFLEXUM (CLONE HC 18) IN DIFFERENT ENVIRONMENTAL CONDITIONS (after 10, 20 and 30 days of culturing; + 3-rad. = triradiate; 4-rad. = tetraradiate; 3-4-rad. = dichotypical c e l l with one semicell t r i r a -diate and the other tetraradiate.) Treatment Percentage Total Percentage Total Percentage Total after 10 days counted after 20 days counted after 30 days counted 3-rad. + 4-rad. + 3-4-rad.+ 3-rad. 4-rad. 3-4-rad. 3-rad. 4-rad. 3-4-rad. T=20°C;1&:8 L:D; Ir radia£4°n=43HE. m .s-1 SPW SW Como Lake water 80.2 12.3 7.5 ——— —— —— ——— ____ 83.6 3.6 11.8 110 90.9 2.9 6.2 242 ECW 87.5 6.7 5.7 297 91.3 6.3 2.8 316 ECW-N . 93.2 3.5 3.3 665 95.1 1.9 3.0 570 ECW-P 91.4 5.1 3.5 603 90.8 4.8 4.4 543 92.5 4.5 3.0 508 Steamed SPW 89.5 5.5 5.0 383 85.7 8.1 6.1 326 76.3 14.9 8.9 389 Sand SPW 82.7 14.8 2.5 81 93.1 6.6 0.5 421 97.1 1.3 1.6 380 SPW medium;18:8 L:D; Irradiation =45ME.m~ .s'-l; pH=4.62 15 °C 86.7 8.1 5.1 349 80.0 7.9 12.0 401 84.6 6.6 8.8 418 10°C 82.1 11.5 6.4 590 86.8 8.3 4.9 456 83.2 9.9 6.8 558 5°C 78.5 11.6 9.8 617 81.7 9.9 8.4 407 77.1 11.5 11.4 384 TABLE 9 (cont'd) Treatment Percentage Total Percentage Total Percentage Total after 10 days counted after 20 days counted after 30 days counted 3-rad. + 4-rad. + 3-4-rad.+ 3-rad. 4-rad. 3-4-rad. 3-rad. 4-rad. 3-4-rad. SPW medium; T= 20°C;16:8 ph>4.62 75 uE.m"2,?-1 68.7 23.5 7.8 520* 61.9 28.0 10.2 619 61.0 26.4 12.6 647 42 jJiE.m" 2^" 1 66.3 25.9 9.9 591 61.8 26.2 12.0 644 64.4 24.1 11.4 617 25 ^E.m"2.s_1 63.7 27.4 8.9 697 62.1 23.2 14.7 640 63.7 24.1@ 12.1 669 SPW medium; T= 20°C;16:8 L : D Irradiations45 $2.m ,s~ pH 6.20 44.8 47.4 7.8 72 4 51.1 46.5 5 . 8 75 7 45.2 4 7.9 6.8 9 30 pH 4.20 60.8 29.1 10.1 650 64.8 25.8 9.3 651 + 62.6 30.5 8.8 658 * 5-radiate =0.2% @ 5-radiate -0.1% + 3-5-radiate =0.2% TABLE 10 C E L L R A D I A T I O N OF STAURASTRUM I N F L E X U M (CLONE HC 18) I N D I F F E R E N T M E D I A AND I N THE F I E L D ( C u l t u r e d a t a f r o m t h e p r e s e n t s t u d y , f i e l d d a t a f r o m M o n c k ( u n p u b l i s h e d ) ) M e d i u m Age o f c u l t u r e R a d i a t i o n (%) i u Lax c o u n t e d ( d a y s ) 3 4 5 6 7 3 - 4 3 - 5 3 - 6 4 - 5 4 - 6 J . K . H e n r y L a k e .0 8 8 . 9 1 1 . 1 5 . 6 36 w a t e r 13 7 6 . 4 1 . 8 1 . 8 1 0 . 9 9 . 1 5 5 20 4 4 . 3 6 . 6 7 . 6 6 . 6 3 4 . 0 106 27 1 6 . 9 1 . 4 2 5 . 4 1 . 4 4 7 . 9 7 . 0 71 34 1 6 . 0 4 . 3 4 7 . 9 4 . 3 2 4 . 5 3 . 2 9 4 41 1 9 . 5 5 4 . 9 0 . 9 0 . 9 2 3 . 9 1 . 8 113 M u n d a y L a k e w a t e r 10 7 6 . 4 7 . 9 9 . 0 4 . 5 2 . 3 89 13 4 7 . 8 2 . 2 8 . 7 8 . 7 3 0 . 4 2 . 1 46 20 5 6 . 6 7 . 1 8 . 1 3 . 0 2 2 . 2 3 . 0 99 34 1 5 . 7 1 .0 5 4 . 9 2 . 9 2 1 . 6 3 . 9 102 41 1 7 . 6 2 . 8 5 4 . 6 0 . 9 0 . 9 1 9 . 4 3 . 7 1 0 8 SPW m e d i u m 10 5 2 . 9 8 . 3 2 . 5 0 . 8 6 . 6 2 2 . 3 0 . 8 5 . 0 0 . 8 1 2 1 13 2 8 . 7 6 . 6 7 . 8 8 . 4 2 3 . 4 0 . 8 4 . 2 16 7 20 5 . 0 5 . 0 2 6 . 3 8 . 8 4 3 . 8 1 1 . 3 80 27 8 . 3 2 . 5 4 7 . 1 0 . 8 3 7 . 2 4 . 1 121 34 5 . 3 4 . 6 6 1 . 4 3 . 0 1 8 . 2 0 . 8 6 . 8 132 41 2 . 9 1 .9 6 6 . 0 3 . 9 1 5 . 5 9 . 7 1 03 J . K . H e n r y L a k e 8 - V I - 8 1 6 8 . 9 1 3 . 7 1 7 . 5 2 4 - V I I - 8 1 9 7 . 4 0 . 7 —— —— 1 . 9 100 G. SUMMARY OF RESULTS AND DISCUSSION Neither laboratory nor f i e l d studies of morphological va r i a t i o n in desmids are perfect. Laboratory cultures cannot reproduce f i e l d conditions. Abnormalities of development are more commonly observed in culture than in nature. Furthermore, i t has been shown that Staurastrum c e l l s in culture are often stouter and may have shorter processes than in c e l l s found in the f i e l d (.Mix 1965, Forster 1 967, Naef et a l . 1978, Brook 1982, present study). Clonal cultures have however the advantage of providing g e n e t i c a l l y homogenous material. P e t e r f i (1972) says that: "...one of the ways to e s t a b l i s h the range of individual variation of Desmids would be that of clonal cultures; however, due to the fact that most Staurastra cannot be c u l t i v a t e d with usual methods, the only way remains the study of natural populations, although such observations cannot be c a r r i e d out systematically, due to the scarceness of suitable populations, especially of rare species." P e t e r f i ' s statement that most "Staurastra cannot be c u l t i v a t e d by usual methods" is very ambiguous. Work by Winter and Biebel (1967), Mix (1965), Forster (1967), Pickett-Heaps (1974), Starr (1978) have proved that Staurastrum can be c u l t i v a t e d . However, none of these authors has done extensive culturing of species showing d i f f e r e n t morphological characters. It i s true that a problem arises with natural populations. Morphological studies of desmid taxa done with f i e l d material rely on the presence of an abundant population of the taxon. Rare taxa are ignored and the only p r a c t i c a l way of study i s by 101 having them multiply in culture and hopefully relate the clonal culture results to f i e l d material. In t h i s study, four hundred and ninety-eight clones were transferred to culture tubes from 1080 c e l l s isolated in well s l i d e s . These c e l l s represented mostly the genus Staurastrum although two taxa of the closely related genus Staurodesmus were also studied. A few other genera of desmids were isolated: Bambusina, Closterium, Cosmarium, Desmidium, Euastrum, Hyalotheca, Micrasterias, Netrium, Pleurotaenium, and Xanthidium, but were not investigated. Of the 498 clones transferred from well slides to culture tubes," about 310 grew including 237 clones of Staurastrum and Staurodesmus. The rate of success of the is o l a t i o n process was 310/1080 or 29%. Twenty-eight taxa of Staurastrum and Staurodesmus were isolated. Some of the cultures grew slowly or had many abnormal c e l l s and when repeated transfer into fresh medium f a i l e d to restore the health of the cultures, they were discarded. Of the remaining clones, 136 were measured and/or observed for morphological variation and percentage of radiation. Some species were represented by only one clone, others by over 20 clones. 102 V. DESCRIPTION AND VARIATION OF SELECTED STAURASTRUM AND STAURODESMUS TAXA A. INTRODUCTION TO TAXONOMIC TREATMENT AND KEY The results presented in Sections A to F are preliminary analyses and experiments which are used as a background for the study of the taxa presented in Chapter V. In Chapter V, observations made on the clonal cultures isolated from f i e l d samples and on the material co l l e c t e d in the f i e l d are compared with the l i t e r a t u r e . The taxa have been arranged in groups of similar morphology and the two taxa of Staurodesmus are treated at the end. The o r i g i n a l descriptions and i l l u s t r a t i o n s of the taxa isolated in culture, and of the v a r i e t i e s and forms belonging to the same species, are given whenever possible. Each of these is examined in regard to the variation observed in clonal cultures and a l i t e r a t u r e review. Related species are also discussed. The taxonomic treatment is very conservative and i t i s considered a p r i o r i t y to f i t specimens to existing taxa, rather than describe new taxa on minor var i a t i o n s . The volume by Prescott et a l . (1982) on Staurastrum (including Staurodesmus) became available at the last stage of completion of t h i s -thesis in December 1983 (despite the 1982 publication date). Since i t constitutes a major and long awaited contribution to the taxonomy of Staurastrum, the book was examined and notes were added to my work under relevant taxa. For example, the synonymy between St. proboscideum (Brebisson) Archer and St. borgeanum Schmidle 103 and the consequent new combinations ( St. proboscideum f. minus (Schmidle) Prescott, Bicudo and Vinyard and St. probosc ideum var. compactum (Gronblad) Prescott, Bicudo and Vinyard) proposed by Prescott et a l . (1982) were already included in my thesis and minor changes had to be made. There are also disagreements between my work and Prescott and coworker's and these are discussed under the appropriate taxa. Data on measurements and radiation (Tables 11-30) as well as SEM and l i g h t microscope photographs (Plates 1-18) follow each taxon studied in clonal culture. Drawing plates (Plates A-R) are given in Appendix D. Abbreviations were detailed in Chapter III, Section B.6. Figure 1 in the introduction i l l u s t r a t e s the main terms used. A key to the taxa studied in clonal cultures i s given hereafter (Staurastrum i s abbreviated as St. and Staurodesmus as Std.): 1a. C e l l with the angles not extended into processes 2 2a. Angles not tipped with spines 3 3a. C e l l wall ornamented with granules 4 4a. Semicell pyramidal St. muricatum var. muricatum 4b. Semicell e l l i p t i c to oval St. alternans var. alternans 3b. C e l l wall ornamented with spines 5 5a. Spines covering most of the c e l l except the i sthmus 1 04 St. brebissonii var, brebissoni i 5b. Spines arranged in a regular pattern; only two of spines on the front of the semicell St. qladiosum var. gladiosum 6a. C e l l wall ornamented with granules St. avicula var. avicula 6b. C e l l wall smooth 7 7a. Apex convex; spines when present straight or convergent Std. mucronatus var. delicatulus 7b. Apex concave or straight; spines when present divergent or upwardly directed Std. dejectus var. dejectus lb. C e l l with angles extended into processes 8 8a. C e l l with accessory processes 9 9a. Accessory processes a p i c a l l y inserted only 10 10a. One accessory process at each angle St. furciqerum var. furcigerum 10b. Two accessory processes at each angle St. furc igerum f. eustephanum 9b. Accessory processes angular as well as apical St. senarium var. senarium 8b. C e l l without accessory processes 11 11a. Processes divergent 12 12a. Processes deeply undulated 105 St. crenulatum var. crenulatum 12b. Processes d e n t i c u l a t e d 13 13a. Base of s e m i c e l l swollen S t . manfeldt i i var. parvum 13b. Base of s e m i c e l l not swollen but s l a n t e d St. tetracerum var. tetracerum 11b. Processes convergent .....14 14a. C e l l u s u a l l y p l u r a d i a t e 15a. C e l l about as long as wide St. sexcostatum var. productum 15b. C e l l wider than long 16 16a. C e l l s m a l l ; width with processes under 50 um S t . arachne v a r . arachne 16b. C e l l b i g g e r ; width with processes over 50 Mm. . 17 17a. T y p i c a l l y s i x or seven p r o c e s s e s ; strong double verrucae on base of processes St. ophiura v a r . ophiura 17b. T y p i c a l l y f i v e or s i x processes; double verrucae on base of processes not as s t r o n g when present S t . pentacerum var. pentacerum 14b. C e l l t r i - or t e t r a r a d i a t e 18 1 06 18a. Processes tipped with two strong spines St. grallatorium var. fore ipiqerum 18b. Processes not tipped with two strong spines 19 19a. Subapical spines or double verrucae present St. vestitum var. vestitum 19b. No subapical spines or double verrucae 20 20a. C e l l t y p i c a l l y twisted at the isthmus; a p i c a l double verrucae rarely present St. inflexum var. inflexum 20b. C e l l not twisted at the isthmus; a p i c a l double verrucae usually present St• probosc ideum f. minor 107 B. STAURASTRUM BREBISSONII VAR. BREBISSONII St. brebissoni i (Brebisson) Archer in Pritchard 1861 (p. 739) Basionym: St. pilosum Brebisson 1856 (p. 141; p i . 2, f i g . 49) PI. A F i g . 1: De Brebisson's description i s : "S. majus, hispidum; hemisomatiis ovato-lanceolatis, a latere secundario triangularibus, angulis rotundatis. "Falaise. Rare. "Les a i g u i l l o n s ou p o i l s dont la surface de cette espece est couverte sont plus longs et plus nombreux vers les angles. La face des hemisomates ou se trouve la suture est assez convexe, de sorte qu'un vide prononce se trouve entre les angles en regard, ce qui n'a pas l i e u dans le St. hirsutum dont les hemisomates sont presque contigus dans toute la face de la suture. Le Phycastrum pilosum Naegeli I.e. t. VIII, A4, ne peut se rapporter i c i . Ses p o i l s sont plus epars et termines par un globule." St. brebi ssoni i was f i r s t described under the name St. pilosum by de Brebisson 1856 but was later transferred to St.  brebi ssoni i since Phycastrum pilosum (named Staurastrum pilosum by Archer in Pritchard 1861, p. 739), had already been used by Nageli 1849 (p. 126; p i . 8A, f i g . 4) for a d i f f e r e n t taxon. This species was not common in the Lower Fraser Valley. It was found in Jacobs and Lost Lakes. Stein and Borden (unpublished) l i s t eight records of St. brebissoni i var. brebissoni i for B r i t i s h Columbia, including Lost and Munday Lakes and three records for the variety brevispinum W. West but none from the lower mainland near Vancouver. St. erasum (discussed later) i s not recorded. St. brebissonii was f i r s t found in Normandy (France) but has since been reported from South America to the A r c t i c . 1 08 Clone examined: HC 70 from Jacobs Lake, 26-VII-79 (see Table 11). In clone HC 70, the semicells are oval to oval-lanceolate in shape with a wide-open acute sinus and short spines forming concentric rings around the angles, about three quarters of the way down the semicell, the area just above the isthmus being free of spines (Pi. 1 F i g . 1-3). The centre of the apex where the concentric rings of spines meet, i s free of ornamentation (Pi. 1 F i g . 4). The spines vary somewhat in length (Pi. 1 Fig. 4, 5) and tend to be longer at the angles (PI. 1 F i g . 6), measuring about 1.5-3 um. Their extremity i s obtusely rounded or truncate ( P i . 1 F i g . 5-7). On PI. 1 F i g . 6 and 7, pore openings can be distinguished on the c e l l wall between the spines. The dimensions of the clone are given in Table 11. The c e l l s of clone HC 70 are on the average s l i g h t l y longer than wide as shown by the L / l r a t i o . Only t r i r a d i a t e c e l l s were seen in culture and f i e l d material (Table 11). West et a l . (1923; p. 62) state that there is a need for good figures of t h i s taxon and that the interpretations given by d i f f e r e n t authors vary considerably. This variation is mostly observed in the shape of the semicell and sinus. Croasdale (1973) for example, shows in her f i g . 14, a c e l l with rounded angles and sinus, whereas the alga in f i g . 13 has d e f i n i t e l y elongated angles and acute sinus. Thomasson (1952) shows an alga with rounded sinus in f i g . 19, but in 1959, he represents a specimen with acute sinus ( f i g . 5). These variations are important in the d i s t i n c t i o n between St. brebissonii and St. 109 erasum Brebisson as w i l l be discussed l a t e r . Most authors show an apex free of spines in v e r t i c a l view (West et aj_ 1923, p i . 138 f i g . 1; Lowe 1923, p i . 4 f i g . 12; Gronblad 1942, p i . 4 f i g . 15, 18; Croasdale 1957, p i . 5 f i g . 89; 1965, p i . 8 f i g . 5, 6; Forster 1970, p i . 27 f i g . 15; Coesel 1979, p i . 26 f i g . 6, 7), although in Croasdale (1973, p i . 18 f i g . 13, 14), the apex is e n t i r e l y covered with sparse spines. The length of the spines also seems to vary s l i g h t l y , as w i l l be discussed under var. brevispinum W. West. 1. Proposed synonyms of St. brebissoni i var. brebissoni i  St. brebissoni i ?forma minor Boldt 1888 St. brebissoni i var. brevispinum W. West 1892 St. erasum de Brebisson 1856. a) St. brebissoni i ?forma minor Boldt 1888 ( p. 36; p i . 2, f i g . 45) PI. A F i g . 2: "...Long. 43,2-45,6 M; l a t . 38,4-42 M; l a t . isthmi 13,2-15,6 M . . . " The type l o c a l i t y of t h i s forma i s Greenland. No further record was found in the l i t e r a t u r e , although Gronblad (1942) places with f. minor a record by Borge (1930) measuring : L(ssp) = 44.5-54.3; Kssp) = 40-57.2; Kcsp) = 44.8-65.8; Is = 13-20; Sp = 2.5-4 urn. This i s too big to be f. minor. Furthermore, Borge notes that his taxon corresponds well to West et a_l.' s (1923; p i . 138, f i g . 1) St. brebissoni i var. 1 10 b r e b i s s o n i i . N e i t h e r d e B r e b i s s o n ( 1 8 5 6 ) n o r A r c h e r ( 1 8 6 1 ) g a v e d i m e n s i o n s f o r t h e t y p e s p e c i e s . I f o n e a c c e p t s W e s t e_t a l . ' s ( 1 9 2 3 ) d i m e n s i o n s f o r t h e t y p e s p e c i e s ( L ( s p ) : 3 4 - 4 8 ; l ( s p ) : 4 0 -6 2 ; I s : 1 3 ; S p ( a t a n g l e s ) : 2 . 5 Mm), B o l d t ' s s p e c i m e n s a r e i n c l u d e d i n t h e s p e c i e s r a n g e a n d t h e r e i s n o n e e d f o r t h i s new f o r m a . I t i s p r o p o s e d t o i n c l u d e t h e f o r m a , w h i c h w a s i n d e e d p u b l i s h e d b y B o l d t p r e c e d e d b y a q u e s t i o n m a r k , a s s y n o n y m o f v a r i e t y b r e b i s s o n i i . b ) S t . b r e b i s s o n i i v a r . b r e v i s p i n u m W. W e s t 1 8 9 2 b ( p . 7 3 1 ; p i . 9 , f i g . 2 6 ) P I . A F i g . 3 : " V a r . s p i n i s b r e v i o r i b u s e t v a l i d i o r i b u s . " L o n g . 4 9 M ; l a t . s . s p i n . 4 2 . 5 M ; l a t . c . s p i n . 4 5 M ; l a t . i s t h m . 1 7 . 5 y . " W. W e s t f i r s t r e c o r d e d t h i s a l g a f r o m t h e L a k e D i s t r i c t i n E n g l a n d . I t h a s b e e n f o u n d i n N o r t h A m e r i c a a n d E u r o p e . A l t h o u g h W. W e s t d o e s n o t g i v e t h e l e n g t h o f t h e s p i n e s o f t h e a l g a , i t c a n b e c a l c u l a t e d f r o m t h e d i f f e r e n c e b e t w e e n t h e w i d t h w i t h a n d w i t h o u t s p i n e s : t h e a n g u l a r s p i n e s m e a s u r e c a . 1 . 2 5 Mm. C e l l s o f c l o n e HC 7 0 h a v e a n g u l a r s p i n e s o f c a . 1 . 5 - 3 Mm, w h i c h i s s l i g h t l y l o n g e r b u t s i m i l a r t o W. W e s t ' s d i m e n s i o n s f o r v a r . b r e v i s p i n u m . R u z i c k a ( 1 9 5 7 ) f o u n d s p e c i m e n s b e l o n g i n g t o v a r . b r e v i s p i n u m w i t h m a x i m u m s p i n e l e n g t h o f 1 . 5 nm. W e s t e_t a l . ( 1 9 2 3 ; p . 6 2 ) g i v e 2 . 5 nm f o r t h e l e n g t h o f t h e a n g u l a r s p i n e s i n t h e t y p e s p e c i e s . F r o m t h e s t u d y o f c l o n e HC 7 0 , t h e l e n g t h o f t h e s p i n e s 111 appears to be a f e a t u r e which shows c o n s i d e r a b l e v a r i a t i o n and thus i s not a good taxonomic c r i t e r i o n (PI. 1 F i g . 5, 6). Comparison of p u b l i s h e d data f o r both v a r i e t i e s brevispinum and b r e b i s s o n i i show that the v a r i a t i o n s i n the l e n g t h of the spines u n d e r l y i n g the c r e a t i o n of var. b r e v i spinum are minute. P u b l i s h e d i l l u s t r a t i o n s of these two v a r i e t i e s are often impossible to d i s t i n g u i s h from each other. For example, Croasdale (1973; p i . 18, f i g . 13) shows a c e l l of St.  b r e b i s s o n i i with spines which appear s h o r t e r than in Schumacher's (1969; f i g . 101) i l l u s t r a t i o n of v a r . brevispinum. Croasdale d e s c r i b e s her specimen has having short s p i n e s . In the l i g h t of the d i f f i c u l t i e s i n v o l v e d i n d i s t i n g u i s h i n g between the two taxa, and of the v a r i a b i l i t y of the d i s t i n c t i v e c h a r a c t e r i s t i c , I propose that v a r . brevispinum be considered as a simple v a r i a t i o n of St. b r e b i s s o n i i and not as a given taxonomic u n i t . c) St. erasum Brebisson 1856 (p. 143; p i . 1, f i g . 28) P i . A F i g . 4 : "S. granulosum; hemisomatii o v o i d e i s g r a n u l o s i s , e dorso convexis, a n g u l i s r o t u n d a t i s s u b s p i n u l o s i s . " F a l a i s e . Rare. "Cette espece p o u r r a i t e t r e placee egalement pres des St• rugulosum, d i l a t a t u m et margaritaceum auxquels e l l e ressemble par sa s u r f a c e granulee. E l l e s'en d i s t i n g u e par quelques epines t r e s c o u r t e s , manquant q u e l q u e f o i s , qui se trouvent au sommet de ses angles et un peu au-dessous." St. erasum and S t . b r e b i s s o n i i (= S t . pilosum Brebisson) 1 1 2 were b o t h d e s c r i b e d by de B r e b i s s o n i n 1856 ( P I . A F i g . 1, 4 ) . The t y p e l o c a l i t y of S t . erasum i s Normandy ( F r a n c e ) , but f u r t h e r p u b l i c a t i o n s l i s t t h e s p e c i e s from A r g e n t i n a t o t h e N o r t h w e s t t e r r i t o r i e s . A l t h o u g h no d i m e n s i o n s a r e g i v e n f o r e i t h e r s p e c i e s , t h e d i f f e r e n c e shown i n t h e shape o f t h e s e m i c e l l seems t o a g r e e w i t h G r o n b l a d ' s a n a l y s i s of t h e s p e c i e s w h i c h i s d i s c u s s e d h e r e a f t e r . G r o n b l a d (1927) r e c o g n i z e s t h a t t h e o r i g i n a l i l l u s t r a t i o n of S t • b r e b i s s o n i i has l e a d t o m i s i n t e r p r e t a t i o n and i n d e e d t h a t t h e S t . b r e b i s s o n i i c o n c e p t seems t o have t a k e n many forms i n t h e l i t e r a t u r e . G r o n b l a d d e c i d e s t o a b i d e by t h e d e s c r i p t i o n of West e_t a l . (1923) who say t h a t t h e d e p r e s s e d s e m i c e l l s , open s i n u s and l o n g e r s p i n e s a t t h e a n g l e s a r e t h e main t a x o n o m i c c h a r a c t e r i s t i c s of t h e s p e c i e s . T h e s e f e a t u r e s a r e f a i r l y w e l l d e f i n e d i n t h e o r i g i n a l f i g u r e of e a c h t a x o n ( P i . A F i g . 1, 4 ) . S t . b r e b i s s o n i i a l s o u s u a l l y has fewer and s h o r t e r s p i n e s t h a n S t . erasum. G r o n b l a d (1942) l a t e r r e v i e w e d h i s d e c i s i o n and e s t a b l i s h e d t h e f o l l o w i n g d i s t i n c t i v e f a c t o r s between S t . b r e b i s s o n i i and t h e c l o s e l y r e l a t e d S t . erasum. S t . b r e b i s s o n i i i s l a r g e r w i t h a w i d t h of about 70 Mm compared t o 40 Mm f o r S t . erasum. I t i s a l s o f u r n i s h e d w i t h s p i n e s , w h i l e S t . erasum has g r a n u l e s on t h e s e m i c e l l s and s h o r t s p i n e s a t t h e a n g l e s . The s e m i c e l l of S t . b r e b i s s o n i i i s o v a l -l a n c e o l a t e w i t h e l o n g a t e d a n g l e s w h i l e i t i s e l l i p t i c w i t h r o u n d e d a n g l e s i n S t . erasum. C r o a s d a l e (1962; p i . 7, f i g . 131), S t . erasum morpha p a r v a has d e f i n i t e l y p o i n t e d as 1 1 3 opposed to rounded angles as shown by de Brebisson (1856, f i g . 28; P i . A F i g . 4) and as emphasized by Gronblad (1942). It may sometimes be very d i f f i c u l t to establish a d i s t i n c t i o n between these two similar species and that may explain the fewer records of St. erasum. Plate 1 F i g . 8 shows one isolated semicell and one c e l l from which one semicell became folded during the processing of the sample for SEM observation. Although the isolated semicell would appear to have elongated angles, the other semicell would better be described as e l l i p t i c with rounded angles. Orig i n a l descriptions of St. erasum and St. brebissoni i are not e x p l i c i t enough and refer to c h a r a c t e r i s t i c s which are too variable to permit a clear d i s t i n c t i o n between the two species. Both species were v a l i d l y published in the same publication, that i s on the same date, thus the p r i n c i p l e of p r i o r i t y does not apply. There have been fewer records of St.  erasum than of St. brebissonii , and I suggest that St. erasum be included as a synonym of St. brebissoni i var. brebissoni i . 2. Other i n f r a s p e c i f i c taxa of St. brebissoni i The following taxa appear d i s t i n c t from St. brebissoni i . They do not present any taxonomic characters observed in variations of clone HC 70 and thus there is no reason not to accept them. St• brebissoni i var. heteracanthum W. et G.S. West 1896b St. brebissoni i var. pauc i spinum Smith 1922 1 1 4 St . brebi ssoni i var. truncatum Gronblad 1926 St. brebissoni i var. laticeps Gronblad 1942 St. brebi ssoni i var. b r a s i l i e n s e Gronblad 1945 St. brebi ssoni i var. curvispinum Gronblad 1945 St. brebissoni i var. maximum Cedercreutz 1932 a) St. brebissoni i var. heteracanthum W. et G. S. West 1896b (p. 260; p i . 16, f i g . 26) P i . A F i g . 5: "Minus, s e m i c e l l u l i s spinis ad angulum unumquenque paucioribus, cum spinis tribus v a l i d i o r i b u s quam spinae reliquae; a ver t i c e lateribus subrectis. "Long. 35 M; l a t . sine spin. 35 u, cum spin. 50 y; l a t . isthm. 11.5 y." This taxon was f i r s t found in North America. No further records were found. With i t s spines grouped at the angles, this taxon d i f f e r s considerably from the type species. b) St. brebissoni i var. paucispinum Smith 1922 (p. 350; p i . 10, f i g . 25; p i . 11, f i g . 1-5) P i . A F i g . 6 : "Cells small, with three or four large spines at the angles and one or two small spines on the apex of the semicells just within the angles. "Length 31-34 y; breadth (without spines) 32-40 y, (with spines) 45-52 y; breadth isthmus 8.5-10 y. "This variety i s quite similar to the variety heterocanthum (sic) but d i f f e r s in the possession of only one or two smaller spines at the c e l l angles and in a general occurrence of four large spines at the angles." 1 15 Smith f i r s t found this taxon in the Muskoka area of Ontario (Canada). No further record was • found. This taxon d i f f e r s s i g n i f i c a n t l y from the type species. Only angular spines are present and the spine pattern i s not c h a r a c t e r i s t i c of St.  brebi ssoni i . Only the shape of the semicell and of the isthmus are s i m i l a r . It is very close to var. heteracanthum . The difference between the two taxa rests solely on minor variation of spine c h a r a c t e r i s t i c s . The description of that variety could possibly be widened to accommodate the d i f f e r e n t features of var. paucispinum, that is the presence of "only one or two small spines at the c e l l angles" and the " general occurrence of four large spines at the angles." (Smith 1922). A more thorough investigation of both taxa i s necessary. c) St. brebissoni i var. truncatum Gronblad 1926 (p. 27; p i . 2, f i g . 85, 86) P i . A F i g . 7: "(syn.=? S_^  pilosum loc. c i t . (W & W, Mngr.V) quoad p i . 138 f. 1). D i f f e r t a forma typica s e m i c e l l u l i s fere trapeziformibus apice truncata dorso a l t i u s convexo; membrana spinis densius obsessa. Long. 41, l a t . 46, isthm. 17 M..." This variety i s not common; Gronblad (1926) f i r s t found i t in Europe and Croasdale (1957) recorded i t in Alaska. It d i f f e r s from the type by the elevated straight apex which gives a trapeziform appearance to the semicell. d) St. brebissonii var. laticeps Gronblad 1942 (p. 41: p i . 4, f i g . 16, 17) PI. A F i g . 8: 116 "Semicellulae latissimae lateribus basalibus convexis usque ad angulos apicales protractos divergentesque; apice subrecto (interdum medio protuso); a vertice visae triangulares lateribus retusis angulis subprotractis angustis. Membrana a c u l e o l i s parvis in ordinibus concentricis d i s p o s i t i s , in angulis i p s i s aculeis nonnullis maioribus. Long. 53 l a t . 70 i s t . 19 M." This taxon was f i r s t found by Gronblad in Swedish Lappland and later (Gronblad 1952) in West Greenland. The diverging angles of t h i s variety are very d i s t i n c t i v e . The taxon i s similar to St. brebissoni i var. brebissoni i in the open sinus, concentric d i s p o s i t i o n of the short spines around the angles and in the longer angular spines. e) St. brebissoni i var. brasi1iense Gronblad 1945 (p. 24; f i g . 198) P i . A Fig. 9: "Semicellulis l a t i o r i b u s , apice medio convexo, angulis quasi p r o t r a c t i s ; aculeis angulorum curvatis. Sine spin. long. 61, l a t . 59, i s t . 17." This taxon was f i r s t found in B r a z i l and has also been recorded in North America and Europe. It has long curved angular spines. f) St. brebi ssoni i var. curvispinum Gronblad 1945 (p.24; f i g . 199) PI. A F i g . 10: " C e l l u l i s non depressis, s e m i c e l l u l i s suboblongis, sinu late aperto, aculeis numerosioribus, omnibus curvatis. Sine spin. long. 95, l a t . 84, i s t . 23." This'variety was f i r s t found in B r a z i l and appears rare. Spinal features are similar to those of var. b r a s i l i e n s e . The spines 1 1 7 are however more numerous, as stated by Gronblad and shown in his f i g . 199 (Pi. A F i g . 10). The semicells of var. curvispinum are also bigger than var. b r a s i l i e n s e . g) St. brebissoni i var. max imum Cedercreutz 1932 (p. 245; t e x t f i g . 14, 15). Neither de Brebisson nor Archer in the description of the species, gave any dimensions for St. brebissoni i . West e_t a l ' s (1923) dimensions for St. brebissonii are given under St.  brebissoni i f. minor (p. 90). Unfortunately, the o r i g i n a l description for var. maximum was not available, but Thomasson (1952) gives Cedercreutz's dimensions as: "long. 87 y, l a t . 87 M", which indicates i t i s d e f i n i t e l y larger than the type species. The dimensions of Thomasson's specimens from Scandinavia are between var. max imum and var. brebissoni i . Gronblad (1936) reported a specimen from Russia which is in the dimension range of var. maximum. Size i s not usually a good taxonomic c r i t e r i o n , although the variation here reported i s almost a doubling in size and can hardly be ignored. Cedercreutz's variety appears to be a d i s t i n c t entity from St. brebissonii var. b r e b i s s o n i i . TABLE .11 CELL DIMENSIONS AND RADIATION OF ST. BREBISSONII (Clonal cultures; N=see Materials and Methods; S.D.=Standard deviation; C V . C o e f f i c i e n t of v a r i a t i o n . F i e l d specimens: N=l; X=presence) Clonal cultures Clone Source HC 70 Jacobs 26-VIII-79 L(csp) (wm) Average Range S.D. C.V. .41 35-45 2.37 5.71 l(csp) Is Average Range S.D. C.V. Average Range S.D. C.V. 37 33-42 2.36 6.38 ;'14 12-17 1.26 9.03 L / l Radiation (%) 3. 1.12 100 F i e l d material Source L(csp) (H.m) l(csp) Oim) Is (um) L / l Radiation 3 Jacobs 26-VII-79 38 36 1.05 X 1 1 9 P l a t e 1 St. b r e b i s s o n i i v a r . b r e b i s s o n i i SEM photographs 1-8. Clone HC 70 1, 3. C e l l i n f r o n t view showing the shape and the spine p a t t e r n 2. Two s e m i c e l l s : l e f t , i n f r o n t view; r i g h t , i n ba s a l view showing the spine p a t t e r n above the isthmus 4. I s o l a t e d s e m i c e l l i n f r o n t view (enlarged view of F i g . 8) 5-7. D e t a i l e d view of angular s p i n e s ; the arrow i n d i c a t e s the pore openings 8. I s o l a t e d s e m i c e l l with elongated angles and whole e l l i p t i c c e l l (one s e m i c e l l folded) with rounded angles 1 20 C. STAURASTRUM GLADIOSUM VAR. GLADIOSUM St. gladiosum Turner 1885 (p. 938; p i . 16, f i g . 21) PI. A F i g . 11: "Species with reniform segments; spines strong, arrayed in series, a few smaller ones scattered; end view triangular, with gently concave sides; ends broadly rounded with six to eight large spines at each; sinus open, expanding rapidly... "Long. 49M = .0019 i n . ; lat.= long.; l a t . isthmi 11-12 M = .00043-47 i n . " From the l i t e r a t u r e , St. gladiosum appears to be a common species which has been reported from d i f f e r e n t areas of the world. In the present study, St. gladiosum was found in Jacobs, Lost, Munday, Como and Placid Lakes, although i t was never very abundant in any of them. Stein and Borden (unpublished) l i s t 35 records of St. gladiosum for B r i t i s h Columbia, including Jacobs, Munday, Lost and Como Lakes; no v a r i e t i e s are recorded. St. teliferum has been recorded 12 times, including Jacobs creek, Como, Lost and Munday Lakes. St. claviferum was found once in the Nanaimo d i s t r i c t . Clones examined: HC 71, 110 from Lost Lake 5-IX-79; HC 496 from Munday Lake 1-XI-80; HC 323 from Como Lake 27-VI-80. Clones discarded because many c e l l s were deformed: HC 132, 135, 148 from Lost Lake, 5-IX-79 (Table 12). Clones of St. gladiosum have oval semicells with rounded angles, s l i g h t l y convex apex and an open acute sinus as seen in front view ( PI. 2, Fig. 1, 5). The c e l l s are almost as long as broad so that the L / l r a t i o is close to 1 (Table 12). A series of, strong spines, ca. 3-8 Mm are present. The spines increase 121 gradually in length towards the c e l l angles (PI. 2, Fig . 2). While the pattern of spines as well as their length and stoutness, varies from c e l l to c e l l , i t always assumes an orderly arrangement. In front view, there are 11-15 spines l i n i n g the margin of the apex between the angles ( P i . 2 Fig. 1,5). Two rows of spines are usually present on the front of the semicell, the one closer to the apex running from one angle to the other, whereas the second row just below i s r e s t r i c t e d to the angles and usually has a gap in the middle (PI. 2 F i g . 3, 4). The rest of the semicell i s free of ornamentation. The spines are widely spaced and not as numerous as in St. brebissoni i var. brebissoni i . When observed with the l i g h t microscope (100 x) or SEM, the front view may show two diverging angular spines, one above the other ( P i . 2 F i g . 3, 6). The v e r t i c a l view shows straight to s l i g h t l y concave margins. The regularly disposed apical spines show some variation in their arrangement (Pi. 2 F i g . 3, 4; PI. B Fig . 8, 9). There are three apical spines just inside the margin, with the central spine usually placed s l i g h t l y above the other two and closer to the centre of the apex. Generally, there i s a. ring or triangle of 12 spines surrounding the centre of the apex, which usually shows some pore openings ( P i . 2 F i g . 4). At high magnification (6700 x) the pore openings appear s l i g h t l y elevated with an opening in their centre ( P i . 2, Fi g . 2). Midway between the angles, on the subapical margin, there i s usually an area free of spines bordered by the spines located closer to the angles ( P i . B Fi g . 8, 9). The width of thi s area 122 varies s l i g h t l y so that, at times, i t appears only as a s l i g h t l y wider space between the spines, halfway between the angles. Only t r i r a d i a t e c e l l s of St. gladiosum have been found in clonal cultures and f i e l d material. No other pattern of radiation or dichotypical c e l l s have been observed. The same is true for l i t e r a t u r e reports consulted. Dimensions obtained for clonal cultures and f i e l d specimens are given in Table 12. Both in clonal culture and f i e l d material, the c e l l s are about as long as broad. The spines of f i e l d material are longer (up to 8 Mm) than cultured material (up to ca. 6 ym). In f i e l d material, the exact point of insertion of the spines is d i f f i c u l t to distinguish because i t is obscured by the protoplasm content of the c e l l s . Variation in size i s observed among clonal cultures, clone HC 71 being the largest (46 x 47 am), followed by clone HC 496 (39 x 39 Mm) and clone HC 110 (38 x 35 Mm). Despite the difference in size, the L / l ratios are si m i l a r . In the f i e l d , c e l l s are s l i g h t l y bigger, with most c e l l s above 40 Mm and one specimen above 50 Mm in length and width (Table 12). A c e l l c o l l e c t e d at the same time and place as clone HC 71 measured 38 x 38 Mm. I l l u s t r a t i o n s of St. gladiosum var. gladiosum in the l i t e r a t u r e b a s i c a l l y agree with Turner 1s o r i g i n a l drawing as well as with the findings of the present study. Brown (1930; p i . 14, f i g . 84, 85) and Hinode (1962; f i g . 92, 93) present only one row of spines l i n i n g each of the three sides of the semicell in a p i c a l view. There are no other spines between the central 123 ring and the margin of the semicell. Prescott (1940; f i g . 7, 8) represents the subapical spines covering the whole margin of the apical view, except for one side where there i s a gap halfway between the angles. He also shows an apical ring of short spines which, contrary to Turner's o r i g i n a l figures, is composed of more than three spines between each angle. Krieger (1932; p i . 15, f i g . 14), Scott and Prescott (1961; p i . 56, f i g . 1), Hinode (1971; f i g . X:3) and Croasdale and Gronblad (1964; p i . 18, f i g . 14) i l l u s t r a t e two rows of apical spines in v e r t i c a l view. In Croasdale and Gronblad (1964) however, the row of spines closer to the margin is missing on one side, so that the apical ornamentation i s composed of one central triangle of spines and one row of spines between the margin and th i s central t r i a n g l e , on two sides only. This variation has been observed in clonal culture ( P i . 2 Fig. 7, 8). 1. Proposed synonyms of St. gladiosum var. gladiosum  St. breviaculeatum Smith 1924b St. c l a v i ferum W. et G.S. West sensu Bourrelly 1966 a) St. breviaculeatum Smith 1924b (p. 78; p i . 70 f i g . 10-18) P i . A F i g . 12: "Cells small, length and breadth about equal, deeply constricted, sinus acute-angled and with apex subacuminate, isthmus narrow; semicells transversely e l l i p t i c , dorsal margin sometimes flattened in the median portion; l a t e r a l angles broadly rounded and bearing four short quadrately arranged divergent spines; c e l l body with two transverse rows of 4-7 spines, the lower row half way between the isthmus and the c e l l apex, the upper midway between the lower row 1 24 and the apex; c e l l apex with median portion bare and with margins towards the angles with 3-4 outwardly pointing spines. V e r t i c a l view triangular, sides of c e l l s emarginate and angles broadly rounded and bearing four quadrately arranged short divergent spines; center of c e l l body with a triangular ring of spines, the sides of the tr i a n g l e lying p a r a l l e l to the margins of the c e l l and each side composed of three outwardly facing spines, angles of the central triangle connected to the corresponding angle of the c e l l by a short row of spines; l a t e r a l margins of c e l l s with 6-8 erect spines and a second arcuate intramarginal row of spines that are of similar size and arrangement; outline of c e l l s l i g h t l y emarginate between adjacent spines. Chloroplast with a small central mass and two laminate blades running to each angle of the c e l l ; pyrenoid single and c e n t r a l . . . "Cells 38-46 u long with spines, 36-42 u long without spines; breadth with spines 37-55 u, without spines 34-44 u; isthmus 9-13 u broad; spines 2-5 u long." St. breviaculeatum has been found in Canada and the United States but does not seem to have been reported in Europe. Smith's figures 10-15 represent the type species, while figures 16-18 are of a forma with shorter spines ( P i . A F i g . 12). Smith's taxon presents b a s i c a l l y the same feature as St.  gladiosum var. gladiosum ; the shape of the c e l l , dimensions and spine pattern are s i m i l a r . Smith notes the presence of two sets of two spines at each angle and, although t h i s c h a r a c t e r i s t i c i s distinguished on his f i g . 11, i t is not as obvious on f i g . 10 on the right side of the upper semicell and c e r t a i n l y not on f i g . 16 and 17. Plate 2 F i g . 3, 5 and 6 of clones HC 71, 148 and 496 i l l u s t r a t e a similar appearance of the spines at the angles. In P i . 2 F i g . 6, the l e v e l of focus permits only two spines to be seen in front view. Smith's i l l u s t r a t i o n s ( f i g . 10, 11) probably represent two spines overlapping each other at each angle; that i s , one spine behind 1 25 the other. Other publicat ions of the species since Smith, do not show Smith's pattern as i l l u s t r a t e d in his f i g . 11 (see Taylor 1935b, p i . 2 f i g . 5; Prescott 1966, p i . 8 f i g . 10, 1 1 ; Thomasson 1962, f i g . 35, 36). Smith states that St. breviaculeatum d i f f e r s from the St.  t e l i ferum-set igerum group by having shorter angular spines which are also the same size as those on the c e l l body. Although the difference i s s l i g h t , specimens observed throughout t h i s study usually had spines which show a gradual elongation towards the angles (Pi. 2 F i g . 3, 5). Observation and measurement of the spines on Smith's figures 11-14, prove that his specimen also showed this s l i g h t difference of the spine length at the angles. West e_t a l . (1923, p. 53) distinguish St. set igerum from other spiny Staurastrum by the presence of two kinds of spines: delicate ones on the body of the semicells and stouter ones at the angles. Whereas th i s is probably the c h a r a c t e r i s t i c Smith was trying to emphasize, his statement that a l l the spines in St. breviaculeatum are of equal length appears inaccurate based on his own i l l u s t r a t i o n s . The spine pattern of St. breviaculeatum in apical view cannot r e a l l y be distinguished from that of St• gladiosum. There i s a central ring or t r i a n g l e of spines with an "arcuate" row between the margin and the central t r i a n g l e . This i s very similar to the observations of t h i s study of three a p i c a l spines with the centre one inserted s l i g h t l y more towards the apex and a central triangle of spines. The spine pattern of St.  breviaculeatum in front view also corresponds to observations 1 26 from the present s tudy . S ince there does not seem to be any we l l d e f i n e d taxonomic c r i t e r i o n to d i s t i n g u i s h between S t .  g lad iosum Turner and S t . b rev i acu l ea tum G.M. Smi th , I propose S t . b r ev i a cu l ea tum as a synonym of the o lde r S t . g l ad iosum. P r e s c o t t et a l . (1982) propose to i n c l ude S t . b r ev i a cu l ea tum as a synonym of S t . c l a v i f e r u m W. et G .S . West 1896b but I do not agree wi th them. The sp ines in S t . c l a v i f e r u m are more numerous than in S t . b r ev i a cu l ea tum and in v e r t i c a l v iew, they are not r e g u l a r l y a r r anged . Whereas there are "two t r a n s v e r s e rows of 4-7 s p i n e s " (Smith 1922) on the c e l l body of S t . b rev i acu l ea tum in f r on t v iew, there are two to four rows of sp ines in West and West ' s f i g u r e . In a p i c a l v iew, the sp ines are s a i d to be i r r e g u l a r l y a r ranged ("cum s p i n i s b rev ibus s u b i r r e g u l a r i t e r o r d i n a t i s " ) by the Wests (1896b) , whereas Smith d e s c r i b e s an o r d e r l y arrangement of a c e n t r a l t r i a n g l e of sp ines connected to each ang le by one row of s p i n e s . P r e s c o t t et a l . (1982; p. 159 p i . 371 f i g . 6) g i ve on ly Sm i th ' s f i g u r e s of S t . b r ev i a cu l ea tum and not the o r i g i n a l i l l u s t r a t i o n s by West and West fo r S t . c l a v i f e r u m . Two v a r i e t i e s of S t . b r ev i a cu l ea tum have been d e s c r i b e d , but no c o n c l u s i o n s can be made u n t i l thorough compar isons wi th other r e l a t e d s p e c i e s i s c a r r i e d o u t . i . S t . b r ev i a cu l ea tum v a r . k a r e l i cum Gronb lad 1936 (p. 10; f i g . 23-24) P I . B F i g . 1 : " D i f f e r t a f r o n t e visum a n g u l i s p lus r o t u n d a t i s , s e m i c e l l u l i s e l l i p t i c i s , s p i n i s p l u s numeros i s ; a v e r t i c e l a t e r i b u s r e t u s i s ; i t aque c e l l u l i s m i n o r i b u s . 1 27 Long. 25, l a t . 25, i s t . 9 M." The spine p a t t e r n of t h i s v a r i e t y found i n North Russia d i f f e r s c o n s i d e r a b l y from that d e s c r i b e d by Smith (1924) for the s p e c i e s . The spines are more numerous in f r o n t view but the a p i c a l spines are l e s s numerous and form only one arcuate r i n g as seen in a p i c a l view. Gronblad's (1936) d e s c r i p t i o n does not s t r e s s the o b v i o u s l y s h o r t e r spines i l l u s t r a t e d by him, but from h i s f i g u r e s ( P i . B F i g . 1), i t appears to be one of the main c h a r a c t e r i s t i c s of h i s taxon. St. breviaculeatum var. karelicum resembles St. t e l i f e r u m f. obtusa W. West (1891; p i . 24, f i g . 6), although the p a t t e r n of spines i s d i f f e r e n t and i t i s s m a l l e r . i i . S t . breviaculeatum var. macracanthum S c o t t et Gronblad 1957 (p. 33; p i . 18, f i g . 1, 2) P i . B F i g . 2: " D i f f e r t s p i n i s m a r g i n a l i b u s et i n t r a m a r g i n a l i b u s (In aspectu v e r t i c a l i ) multo l o n g i o r i b u s , s p i n i s angulorum r o b u s t i o r i b u s ; s i n u minus a p e r t o . Long. csp. 39-41, ssp. 35-38, l a t . csp. 42-49, ssp. 33-39, i s t . 11-13." T h i s v a r i e t y was f i r s t found i n M i s s i s s i p i (U.S.A.) and l a t e r r e p o r t e d by F o r s t e r (1972) from the same s t a t e . I t i s d e s c r i b e d as having longer marginal and i n t r a m a r g i n a l spines i n a p i c a l view and s t o u t e r angular s p i n e s . As d i s c u s s e d p r e v i o u s l y , Smith's i l l u s t r a t i o n s of St• breviaculeatum do show longer spines towards the a n g l e s . N e i t h e r h i s i l l u s t r a t i o n s nor o b s e r v a t i o n s i n the present study have shown that the angular spines are s t o u t e r ; they are a l s o d i r e c t e d toward the isthmus. 1 28 The sinus i s not as open as in St. breviaculeatum and St.  gladiosum and has straight margins. This taxon i s transferred to St. claviferum by Prescott et a l . (1982, p. 158) but as discussed previously, their interpretation is not accepted. b) St. claviferum W. et G.S. West 1896b (p. 259; p i . 16 f i g . 25) sensu Bourrelly 1966 (p. 114; p i . 20, f i g . 5, 6) P i . B F i g . 7: The Wests' i l l u s t r a t i o n of this species shows more numerous and shorter spines of a d i f f e r e n t pattern than observed in St.  gladiosum var. gladiosum. West and West f i r s t found this taxon in the United States. It has since been found in the Trois-Rivieres area (Quebec, Canada) by Irenee-Marie (1949a) and in New Hampshire by Cushman (1905b). One report by Bourrelly (1966) from Algonquin Park (Ontario, Canada), appears to be more close l y related to St. gladiosum than to St. claviferum. 2. Other i n f r a s p e c i f i c taxa of St. gladiosum The taxonomic c h a r a c t e r i s t i c s of the following v a r i e t i e s have not been observed in clonal cultures or f i e l d material and there are no reasons not to accept them at the present time. St. gladiosum var. lonqispinum Turner 1892 St-, gladiosum var. delicatulum W. et G.S. West 1900 a) St. gladiosum var. lonqispinum Turner 1892 (p. 112; p i . 17 f i g . 2) PI. A F i g . 14: "Spinulis valde elongatis, longitudine i r r e g u l a r i b u s . 1 29 "Long. 46, l a t . 48, l a t . i s t h . 13, long. spin. 9-17 Turner describes the variety he found in India, as having long spines of variable length. As seen by his figures, the spines are longer at the angles, but their d i s p o s i t i o n i s very much l i k e the type species as well as the specimens observed in the course of thi s study. This variety should be compared to St.  lonqirostratum Gronblad 1920 ( p i . 1, f i g . 20, 21). Gronblad describes his species as: "Cellulae mediocres medio sinu acuto extrorsum aperto regul a r i t e r ampliato profunde constrictae. Semicellulae a fronte visae depresse e l l i p t i c a e , dorso convexo late arcuato, angulis rotundatis; a vertice visae triangulae lateribus medio l e v i t e r r etusis, angulis rotundatis vel subtruncatis; membrana spinis longis in series regulariter d i s p o s i t i s armata, a vertice visa in area c e n t r a l i triangula glabra, sed ceterum spinis in series tres cum marginibus p a r a l l e l a s d i s p o s i t i s (quarum una series in ipso margine, r e l i q u i intra hos) instructa; a fronte in unoquoque angulo spinae singulae longiores et robustiores oblique (sub angulis in dorso) defixae conspiciuntur. Cum spin. long. 60, l a t . 68, sine spin. long. 46, l a t . 49, isthm. 18, spinae longiss. 15, spin, breviss. 8 M." Gronblad's i l l u s t r a t i o n s of the species do show a front view with one angle protruding in the middle of the semicell. This is unfortunate since i t does not show the spine pattern on the front of the semicell. Both species do show a c h a r a c t e r i s t i c of St. set igerum stressed by West et a_l. (1923) and mentioned e a r l i e r , that i s stout angular spines and more delicate body spines. This i s not a feature observed in the material found in the present study and more thorough investigation of the species complex having t h i s feature would be necessary before drawing 1 30 any conclusion. Gronblad (1948) expresses doubts about the v a l i d i t y of t h i s species. b) St. gladiosum var. delicatulum W. et G.S. West 1900 (p. 296; p i . 412, f i g . 14) P i . A F i g . 15: "Var. spinis d e l i c a t i o r i o b u s , interdum l e v i t e r curvatis, paucioribus inter angulos. Long, sine spin. 37.5 M, cum spin. 44 M; l a t . sine spin. 38.5 M, cum spin. 50 M; l a t . isthm. 14 y." This variety was f i r s t found in Malham tarn in West Yorkshire (England); Coesel (1979) found i t in Holland. In apical view, the spines are less numerous than in the type species, with only a few scattered spines bordering the margin between the angles. In front view, the sinus is more widely open and more rounded than observed in the present study and correspond to Turner's figure of the type species (PI. A F i g . 11). Coesel (1979; p i . 26, f i g . 2, 3) shows one front view of the variety with a closed and rounded sinus and a second one with an acute and more open sinus. 3. Uncertain i n f r a s p e c i f i c taxon of St. gladiosum Forma ornata Laporte 1931 Mention of t h i s forma was found in Messikommer (1942; p i . 17, f i g . 1), however the o r i g i n a l description was not ava i l a b l e . From Messikommer's figure, t h i s forma appears to be based on the stouter and probably longer spines. The spine pattern i s b a s i c a l l y similar to the type species. 131 4. Taxa related to St. gladiosum Although few v a r i e t i e s and formae of St. gladiosum have been described, some species are very closely a l l i e d to i t and should be discussed here. Many well established species share the basic spine pattern observed in St. gladiosum. Some of them are also distinguished by other r e l i a b l e taxonomic c h a r a c t e r i s t i c s while in others, i t is d i f f i c u l t to see the basis for the recognition of separate species. St. teliferum Ralfs 1848 St. t e l i ferum var. ordinatum Borgesen 1894 St. t e l i ferum var. subteli ferum (Roy et Bisset) Forster 1 970 a) St. teliferum Ralfs 1848 (p. 128; p i . 22 f i g . 4, p i . 34 f i g . 14) PI. B F i g . 3 : "...segments reniform, b r i s t l y ; end view triangular, with concave sides and broadly-rounded b r i s t l y angles..." "Frond about as large as that of Staurastrum hirsutum, deeply constricted at the middle; segments twice as broad as long, somewhat reniform, and furnished with scattered spines. End view triangular; the spines variable in number and confined to the angles. " Staurastrum teliferum d i f f e r s from Sj_ hi rsutum i n i t s longer spines, which are also fewer, stouter, and in the end view confined to the angles. It is a larger plant than S_^  H i s t r i x ; i t s spines are more numerous, and the end margins in the front view are convex. "Length of frond 1/597 of an inch; breadth 1/643; breadth at co n s t r i c t i o n 1/2041; length of spine 1/4098; diameter of sporangium 1/738; length of spine of sporangium 1/2066." 1 32 The subsequent interpretations given to St. t e l i ferum by d i f f e r e n t authors have varied widely. West et a l . (1923) describe St. teliferum as, "one of the most widely d i s t r i b u t e d of the B r i t i s h Desmids". Such a statement may also hide a d i f f e r e n t fact, that i t is indeed one of the most broadly interpreted species reported in B r i t a i n . West e_t a_l.'s figures ( p i . 236, f i g . 2-6) d i f f e r from Ralfs' (PI. B F i g . 3) in having a more open sinus and by showing an apical ring of spines in v e r t i c a l view. Ralfs shows only a few apical spines clustered around the angles, and states that i t i s "furnished with scattered spines." I l l u s t r a t i o n s of the species by later authors do show, in ap i c a l view, a more or less well defined apical ring of spines as represented by West e_t a l . and, furthermore, often have extra apical spines between the ring of spines and the margin of the semicell (Taylor 1935a, p i . 35 f i g . 3; Croasdale and Gronblad 1964, p i . 18 f i g . 15, 16; Messikommer 1938, p i . 10 f i g . 106). Croasdale and Gronblad 1964 (p. 206 p i . 18 f i g . 15, 16) do show some interesting variation in their specimens. Their f i g . 16 i l l u s t r a t e s , in apical view, one well-defined intramarginal ring of spines with a d e f i n i t e gap in i t s centre and the spines clustered around the angles. Their f i g . 15 shows three intramarginal spines on two sides of the semicell in apical view; however, the t h i r d side has two more or less defined rows of intramarginal spines. The space between the marginal spines i s wider halfway between the angles, but there is no well defined gap. Croasdale and Gronblad note: "...spines 1 33 to some extent grouped at angles." Their findings are in keeping with the variation in the width of the central gap between marginal spines observed in apical view in clones HC of St. gladiosum (P i . 2 F i g . 3, 4). This also shows a t r a n s i t i o n between the species St. teliferum pictured by West e_t a l . (1923) and St. gladiosum Turner. A careful observation of Turner's figure of St. gladiosum shows that at least on the right side of the semicell shown in apical view in his figure 21 (PI. A F i g . 11), there i s a d e f i n i t e gap halfway between the angles, the spines close to the margin being intramarginal and not marginal. The species St. teliferum needs to be reevaluated as i t s common interpretation d i f f e r s from the information which can be gathered from Ralfs' o r i g i n a l figures. b) St. teliferum var. ordinatum Borgesen 1894 (p. 27; p i . 2, f i g . 23) PI. A F i g . 13: "A forma typica d i f f e r t spinis non sine ordine d i s p o s i t i s ; semicellulae a fronte visae apicibus c i r c i t e r 13 spinis ornatis, a vertice visae medio glabro ad marginem versus 12 spinis in orbem triangularum d i s p o s i t i s , margine etiam s p i n i f e r a . "Long. = 38 M; l a t . sine spin. =33 y..." This variety was f i r s t found in Greenland and has since been reported from Europe. This variety does d i f f e r from Ralfs' o r i g i n a l i l l u s t r a t i o n s of St. teliferum through the arrangement of the spines. Comparison of Turner's o r i g i n a l figure of St.  gladiosum (P i . A F i g . 11) and of Borgesen's i l l u s t r a t i o n (Pi. A F i g . 13) of St. teliferum var. ordinatum show that both in 1 34 front and v e r t i c a l views, the spines are s i m i l a r l y arranged. There are two rows of spines on the front of the semicell and in apical view, there i s a central t r i a n g l e of spines and l a t e r a l spines. However St. t e l i ferum var. ordinatum has shorter spines and i s s l i g h t l y smaller than St. gladiosum. It seems to correspond more closely to St. gladiosum than to St.  teliferum. Capdevielle and Coute (1980) published some detailed drawings and SEM photographs of St. teliferum var. ordinatum. The authors mention that their taxon d i f f e r s from Borgesen's by being about as long as broad, a difference which is minimal since Borgesen's L / l r a t i o would be 1.15. They also note that the apical ring of spines in apical view i s composed of 12 spines in their specimens and of nine in the variety. This is not accurate as Borgesen i l l u s t r a t e s c l e a r l y a ring composed of three spines l i n i n g each three margins of the semicell plus one spine at the t i p of each t r i a n g l e . From their references, i t seems that Capdevielle and Coute observed Forster's (1970; p i . 27, f i g . 18) i l l u s t r a t i o n of St. teliferum var. ordinatum. The spines closing the ring at each angle are placed s l i g h t l y closer to the angle, which gives the impression that there are only nine central spines. The SEM photographs of Capdevielle and Coute show a less open sinus than in Borgesen's figure. Plate 27 f i g . 18 in Forster (1970) and p i . 14 f i g . 23 ( l e f t ) in Ruzicka (1973) i l l u s t r a t e a sinus not as widely open as in Borgesen's figure. Ruzicka (1973, p i . 14 f i g . 23; right) i l l u s t r a t e s a sinus which is more widely open than in Capdevielle and Coute p i . 2, f i g . 6-9 and in HC clones. 1 35 c) St. t e l i f e r u m var. s u b t e l i f e r u m (Roy et B i s s e t ) F o r s t e r 1 9 7 0 (p. 3 4 2 ; p i . 2 7 , f i g . 1 6 , 17 ) PI. B F i g . 4 Basionym: S t . s u b t e l i f e r u m Roy et B i s s e t 1886 (p. 2 3 8 ; p i . 2 6 8 , f i g . 1 ) PI. B F i g . 5 : Roy and B i s s e t d e s c r i p t i o n f o l l o w s : "Medium-sized, s l i g h t l y longer than broad: s e m i c e l l s i n f r o n t view r e g u l a r l y o v a l , with three stout spines on each s i d e , 2-3 s i m i l a r to and near to these on the face of the s e m i c e l l s , and two small spines c l o s e to the end; end view t r i a n g u l a r , with three superposed stout spines t e r m i n a t i n g each angle, and two s i m i l a r ones on each s i d e of i t ; nearer the c e n t r e of the t r i a n g l e i s a c i r c l e of nine minute s p i n e s , s i d e s concave; c o n s t r i c t i o n acute, opening out widely. Membrane smooth. Long. 37 u; l a t . 3 5 u; l a t . of i s t h . 13 M . " T h i s taxon was f i r s t found in Japan. F o r s t e r ( 1 9 7 0 ) recorded i t from Germany. F o r s t e r ( 1 9 7 0 ) t r a n s f e r r e d St. s u b t e l i ferum i n St. t e l i f e r u m as a v a r i e t y , on the b a s i s of the arrangement of the s p i n e s . H i s f i g u r e s ( P i . B F i g . 4 ) d i f f e r i n many r e s p e c t s from those of Roy and B i s s e t ' s f i g . 1 (see P i . B, F i g . 5 ) . F o r s t e r d i d not take i n t o c o n s i d e r a t i o n the p r i n c i p a l c h a r a c t e r i s t i c of the s p e c i e s ; that i s , the longer spines at the angles, which i s very c l e a r l y shown on Roy and B i s s e t ' s f i g u r e s , but i s t o t a l l y m i s s i n g from F o r s t e r ' s f i g u r e s . St. s u b t e l i ferum Roy et B i s s e t and St. t e l i ferum v a r . s u b t e l i f e r u m F o r s t e r do not seem to belong to the same taxon. Roy and B i s s e t ' s taxon i s smaller than St. set igerum but the presence of two types of spines at the angles and on the body should j u s t i f y i t s c l a s s i f i c a t i o n under that s p e c i e s . In s i z e i t i s s i m i l a r to St. setigerum v a r . o c c i d e n t a l e W. et 1 36 G.S. West 1896b (p. 260; p i . 16, f i g . 27), although i t is a b i t longer than broad. Furthermore, both taxa are very similar in apical view as pointed out by Smith (1924b). The semicells of St. subteli ferum in front view are oval and not narrowly e l l i p t i c with elongated angles as in var. occ identale. Roy and Bisset do not give the length for the two types of spines of St. subteli ferum. It has been shown e a r l i e r that in St gladiosum, the spines are s l i g h t l y longer at the angles. On th i s basis, St. subteliferum resembles St. gladiosum var. delicatulum which possesses long and curved spines and i s of similar dimensions, although the spines are more regularly disposed in St. subteliferum. d) Conclusion I think that St. teliferum var. ordinatum and many publications of St. teliferum var. teliferum might be synonymous with St. gladiosum var. gladiosum. I agree with Forster that the features of St. subteli ferum do not j u s t i f y the naming of a separate species but I do not believe that Forster's specimens are the same as St. subteliferum. With i t s short spines, Forster's taxon i s similar to St. teliferum var. ordinatum. A more thorough investigation i s needed before making further conclusions about those taxa. TABLE }2 CELL DIMENSIONS AND RADIATION OF ST. GLADIOSUM (Clonal cultures; N=see Materials and Methods; S.D.=Standard deviation; C . V . C o e f f i c i e n t of v a r i a t i o n . F i e l d specimens: N=l; X=presence) Clonal cultures Clone Source HC L(csp) (um) l(csp) (»m) Is (um) L / l Radiation (%) Average Range S.D. C.V. Average Range S.D. C.V. Average Range S.D. C.V. 3 71 Lost 5-IX-79 46 39-51 2.39 5.17 47 39-52 3.12 6.67 17 14-18 1.03 6.21 0.99 100 110 Lost 5-IX-79 38 32-53 4.09 10.90 35 29-52 4.24 12.25 14 12-20 1.38 10.12 1.08 100 496 Munday l-XI-80 39 36-43 1.85 4.86 39 35-44 2.68 6.86 16 14-18 0.80 5.70 1.00 100 323 Como 27-VI-80 37 32-45 3.20 8.56 37 32-41 2.38 6.38 14 12-17 1.32 9.68 1.00 100 F i e l d material Source L(csp) (Mm) L(ssp) (um) l(csp) (wm) l(ssp) (wm) Is (Mm) L / l Radiation 3 Jacobs 22-VIII-79 44 41 47 38 14 0.93 X Jacobs 26-IV-80 41 38 43 34 12 0.95 X II It 52 44 51 39 — 1.03 X II t l 49 41 46 36 14 1.07 X Lost 5-IX-79 38 38 41 32 12 0.93 X Lost 18-VII-80 44 40 47 35 13 0.93 X Lost 20-IX-80 44 44 42 34 16 1.05 X Lost ll-X-80 44 42 44 35 17 1.00 X Placid 8-VIII-80 43 37 46 37 16 0.93 X 1 38 Plate 2 St. gladiosum var. gladiosum (marker= 10 um unless indicated otherwise) 1. Clone HC 71, l i g h t microscope photograph; c e l l in front view showing the spine pattern 2-4. Clone HC 71, SEM photographs. 2. Detailed view of one angle showing the spines and the pores. 3. C e l l in v e r t i c a l view showing the spine arrangement 4. Isolated semicell viewed from the front and the apex showing the spine pattern 5. Clone HC 148, SEM photograph; two c e l l s in front view 6. 7. Clone HC 496, l i g h t microscope photographs; C e l l s in front view showing the spine pattern I3*A 1 39 D. STAURASTRUM ALTERNANS VAR. ALTERNANS St. alternans Brebisson ex Ralfs 1848 (p. 132; p i . 21, f i g . 7) PI. B F i g . 10: "...segments rough, narrow-oblong, and, from their twisted position, unequal in the front view; end view with the angles of one segment entire, and alternating with those of the other... "Frond rough with minute pearly granules, which, except on the margin, appear l i k e puncta; segments two or three times longer than broad, oblong, twisted, so that in the front view one of them appears shorter on one side, in consequence of the blending together of two of the angles. The end view is triangular, with concave sides and very obtuse entire angles. The angles of the lower segment are seen alternating with those of the upper. "I formerly described this plant as the Staurastrum  tricorne, but that species in the front view i s prolonged at the sides into short processes; I am not certain that the two are d i s t i n c t , but in doubtful points I think i t right to defer to M. de Brebisson's opinion. " Staurast rum alternans may be known from S.  dilatatum and S^ punctulatum by i t s unequal segments in the front view and alternating angles in the end one. "I have gathered the sporangia at Penzance; they are orbicular and furnished with spines forked at the apex. "Length of frond 1/1037 of an inch; breadth 1/1106; breadth at co n s t r i c t i o n 1/3205..." St. alternans was found in J. K. Henry, Como, Munday and Jacobs Lakes, but never in abundance. In Stein and Borden (unpublished), 22 records of St• alternans are l i s t e d for B r i t i s h Columbia, including Munday Lake. St. punctulatum var. punctulatum has 66 records, including Munday, Lost and Como Lakes. 1 40 Clones examined: HC 205 from J.K. Henry Lake, 18-IV-80; HC 438 from Munday Lake, 16-V-80 (Table 13). Ce l l s are about as long as wide with a L / l r a t i o of ca. 1 (Table 13). The semicells of St. alternans are usually e l l i p t i c - l a n c e o l a t e in shape with rounded angles (PI. 3 F i g . 1). Some semicells have a more e l l i p t i c and less lanceolate shape, the semicells appearing f u l l e r (PI. 3 F i g . 4). This i s p a r t i c u l a r l y true for clone HC 438 where the c e l l s would be better described as oval rather than e l l i p t i c - l a n c e o l a t e . The apex i s s l i g h t l y convex. C e l l s with semicells of s l i g h t l y d i f f e r e n t width were observed in clonal cultures and f i e l d mater i a l . The sinus is either acute ( P i . 3 Fig. 2, 3) or rounded (PI. 3 F i g . 4). Many semicells alternate s l i g h t l y ( P i . 3 F i g . 2, 4), but others have their angles lying exactly above each other (PI. 3 F i g . 6). Granules form concentric rows around the angles of the semicells ( P i . 3 F i g . 3). They cover most of the c e l l except for the area surrounding the isthmus (Pi. 3 F i g . 3, 4). Depending on the degree of development of the granulation, the sides and angles of the semicells w i l l appear either smooth or granulate under the l i g h t microscope. No defined row of supraisthmial granules was seen. The granulation varies considerably in coarseness (PI. 3 F i g . 1, 5). PI. 3 F i g . 9 is a close-up of a c e l l with heavy ornamentation where the rugged and irregular shape of these "granules" is e a s i l y observed. Lines of what may be mucilage 141 seems to connect some granules together. Such p a r t i c u l a r ornamentation is also seen with the l i g h t microscope. The ornamentation appears l i k e rounded flattened granules (Pi. 3 F i g . 8) or concentric rows of more delicate granules (PI. 3 F i g . 7). In apical view, the sides of the c e l l s are s l i g h t l y concave or almost straight (PI. 3 F i g . 6). Also noticeable is the difference in protrusion of the angles. In P i . 3 F i g . 6 the top semicell has rounded angles that are shorter and not as elongate as i t s s i s t e r semicell beneath i t . The ornamentation covers the whole apex of the semicell even i t s central part. In P i . 3 F i g . 6, a central rosette of granules is seen on the centre of the apex. The granulation, v i s i b l e on the side of the semicells in a p i c a l view, gives an uneven appearance ( P i . 3 F i g . 6). The dimensions of the clones are given in Table 13. A l l c e l l s observed in f i e l d and clonal cultures were t r i r a d i a t e . Clones HC 205 and 438 were both observed with a l i g h t microscope, although only clone HC 205 was processed for SEM observation. I l l u s t r a t i o n s of St. alternans in the l i t e r a t u r e , show a considerable degree of v a r i a t i o n . Although St. alternans was described by Ralfs as having alternating semicells, West and West (1912) stress that t h i s can not be a s p e c i f i c c h a r a c t e r i s t i c since i t i s common in other related Staurastrum. This c h a r a c t e r i s t i c was seen in a l l f i e l d specimens observed but varied in cultures as previously noted. Many i l l u s t r a t i o n s represent a perfect alternation between 1 42 the two semicells in v e r t i c a l view (Archer 1861, p i . 2 f i g . 16, 17-; West and West 1912, p i . 136 f i g . 8; Allorge and Allorge 1931, p i . 12 f i g . 14, 15; Croasdale 1962, p i . 7 f i g . 125; Hinode 1971, f i g . IX:21; Ruzicka 1973, p i . 14 f i g . 20), while others i l l u s t r a t e some degree of twisting of the isthmus but not s u f f i c i e n t to have the angles alternate perfectly with each other (Forster 1965, p i . 8 f i g . 15; Coesel 1979, p i . 24 f i g . 4, 5). Most c e l l s of clones HC 205 and 438 did show some degree of twisting, but rarely were the two semicells in perfect alternation with each other. Some authors show only a single semicell in apical view, which suggests that the semicells were not showing any degree of alternation and that the angles lay perfectly above each other (Taylor 1935a, p i . 35 f i g . 6; Krieger and Scott 1957, p i . 5 f i g . 2; Gronblad 1960, f i g . 215, 216). West and West (1912; p i . 136, f i g . 8) show two c e l l s with s l i g h t l y d i f f e r e n t sinus shape. Figure 8a represents a close and acute sinus whereas the sinus in f i g . 8a' i s more widely open. Coesel (1979; p i . 24, f i g . 4) i l l u s t r a t e s an alga very similar to the Wests f i g . 8a' and which also has a row of granules just above the isthmus whereas the c e l l in his f i g . 4 has a less open and more rounded sinus. Such variation in the degree of opening of the sinus and in i t s shape from rounded to acute, occurs in the l i t e r a t u r e and has been observed to some extent in clones HC 205 and 438 ( P i . 3 Fig. 1, 4). The presence of a well defined row of supraisthmial granules was never observed, but the width of the space free of ornamentation above the isthmus varies. Literature reports also 1 43 represent t h i s v a r i a t i o n ; for example Smith (1924b; p i . 6, f i g . 4) represents a specimen where the ornamentation covers almost the whole isthmial area, whereas in Krieger and Scott (1957; p i . 5, f i g . 2) and Ruzicka (1973; p i . 14, f i g . 20), there is a wide area free of ornamentation above and below the i sthmus. Although specimens in clones HC 205 and 438 always show granulation on the centre of the apex in apical view, some authors represent the c e l l s with a smooth apex (Krieger and Scott 1957, p i . 5 f i g . 2; Croasdale 1962, p i . 7 f i g . 125). The strength of the ornamentation also seems to vary, judging by i t s representation on drawings by d i f f e r e n t authors. Allorge and Allorge (1931; p i . 12, f i g . 14, 15), Taylor (1935a; p i . 35, f i g . 6) and Krieger and Scott (1957; p i . 5, f i g . 2) represent the granules as small c i r c l e s . Coesel (1979; p i . 24, f i g . 4, 5) shows the granules by very delicate dots. A range of d i f f e r e n t intensity of granulation between these extremes are i l l u s t r a t e d in other publications. These i l l u s t r a t i o n s seem to agree with the important v a r i a t i o n in the i n t e n s i t i e s of granulation observed in clones HC 205 and 438, from delicate granules to rugged prominent granules (Pi. 3 F i g . 4, 5, 7, 8). 1. Proposed synonyms of St. alternans var. alternans:  St. alternans var. subalternans Maskell 1888 St. punctulatum forma e l l i p t i c u m Lewin 1885. a) St. alternans var. subalternans Maskell 1888 (p. 22; p i . 4, 1 44 f i g . 38) PI. B F i g . 11: "Frond small; segments in front-view s u b - e l l i p t i c a l ; when viewed s l i g h t l y t i l t e d (as in the figure) the t h i r d angles of the two segments are not exactly opposite. In end-view, segments triangular, sides concave, angles rounded; the frond being only s l i g h t l y twisted, the angles of each segment are neither quite in correspondence nor quite alternate. Cytioderm punctate, the puncta transverse. "Long., 25 M; l a t . , 26.7 M..." This variety was f i r s t found in New Zealand. No further records were found. Since i t is based solely on the degree of torsion of the isthmus which is a highly variable c h a r a c t e r i s t i c as discussed previously, i t can not be recognized as a true variety. b) St. punctulatum forma e l l i p t i c u m Lewin 1888 (p. 9; p i . 1, f i g . 16) The o r i g i n a l description of t h i s forma was not available and i t appears to be rare. Krieger (1932; p i . 15, f i g . 10; P i . B F i g . 12) gives under the name var. e l l i p t icum forma, a form with e l l i p t i c semicells, rounded angles and concave sides in v e r t i c a l view. Although West and West (1912; p. 146) did not observe this taxon, they express the opinion that i t may belong to St. alternans and their conclusion i s accepted. 2. Other i n f r a s p e c i f i c taxa of St. alternans A number of v a r i e t i e s and forms of St. alternans have been described in the l i t e r a t u r e and, based on observations of the present study and l i t e r a t u r e reports, there i s no ground not to 1 45 accept them. Some have been placed by other authors as synonyms of d i f f e r e n t taxa. St. alternans var. pulchrum Wille 1879 St. alternans var. minus Turner 1892 St. alternans var. basichondrum Schmidle 1898 St. alternans var. basichondrum f. tetragonum Croasdale et Gronblad 1964 St. alternans var. divergens W. et G.S. West 1902a St. alternans var. spinulosum Irenee-Marie and H i l l i a r d 1 963 a) St. alternans var. pulchrum Wille 1879 (p. 53; p i . 13, f i g . 66) PI. B F i g . 13: "S. fere tarn longum quam latum, sinu subrectangulo ampliato constrictum; semicellulae e basi angusta sursum valde di l a t a t a e , subcuneiformes, dorso truncato 1. late rotundato, angulis magis minus rotundato-obtusis; a vertice visae trigonae angulis rotundatis, lateribus r e t u s i s . Membrana granulata, margine granulato dentata. "Long. 32; l a t . 30; l a t . isthm. 10 M." This variety i s not common but has been reported in di f f e r e n t areas of the world. Wille's plant i s s l i g h t l y longer than broad and has a subrectangular sinus with the base of the semicell s l i g h t l y concave. b) St. alternans var. minus Turner 1892 (p. 105; p i . 16, f i g . 6) PI. C F i g . 1: "Multo minor quam F. typica. 1 46 "Long, et l a t . 15, l a t . i s t h . 9.5 y." This variety f i r s t described from East India, does not appear to have been recorded since. It has a rounded sinus and the granulation i s r e s t r i c t e d to the angles. It resembles St.  striolatum (Nageli) Archer, which, according to West and West (1912; p. 178), measures 19-28 by 18-28 ym with an isthmus 6-10 ym wide. c) St. alternans var. basichondrum Schmidle 1898 (p. 58; p i . 3, f i g . 6) PI. C F i g . 2: This variety was found in northern areas. Only the i l l u s t r a t i o n of th i s taxon was available. Croasdale (1962) reports this taxon as var. basichondrum Schmidle 1898, although Schmidle reports i t in the legend as St. alternans v. In West and West (1912; p. 170), i t is l i s t e d as a record of St.  alternans. Apart from the naked apex in apical view and the row of supraisthmial granules in front view, the main difference from the type species seems to be the shape of the sinus. Some i l l u s t r a t i o n s of St. alternans ( West and West 1912, p i . 126, f i g . 8a'; Coesel 1979, p i . 24 f i g . 24) show a wide open sinus ending in a small acute notch and are similar to var. basichondrum. The d i s t i n c t i o n between the species and i t s variety appears to be based on s l i g h t variations and more thorough investigation may prove that there i s no ground to separate these taxa. Croasdale (1962) and Croasdale and Gronblad (1964) represent c e l l s of var. basichondrum with f a i r l y elongated 1 47 angles which form short processes with rounded extremities. The sinus is very d e f i n i t e l y rounded and d i f f e r s from Schmidle's f i g . 6 ( P i . C Fig. 4). Croasdale (1962) expresses some doubts about her c l a s s i f i c a t i o n . d) St. alternans var. basichondrum f. tetragonum Croasdale et Gronblad 1964 ( p. 194; p i . 18, f i g . 4, 5) P i . C F i g . 5: "Cellulae 34 u x34 u, i s t h . 19 u et 38-40 u x39-42 u, i s t h . 16-17 ix. Semicellulae a ver t i c e visae tetragonae. "Semicells tetragonal in v e r t i c a l view. The plants appeared in two morphae: Fig. 4 shows a small angular plant 34 M x 34 a, i s t h . 9 u (Sta. 21), and F i g . 5 shows a larger plant with rounded angles, 38-40 u x39-42 u, i s t h . 16-17 u (Sta. 16). This i d e n t i f i c a t i o n i s uncertain. Except for the supraisthmial c i r c l e of granules and the somewhat irregular granulation in v e r t i c a l view these plants might be c l a s s i f i e d as S.  dilatatum Ehr. Except for the larger size and more extended angles they might be c l a s s i f i e d as S.  marqaritaceum (Ehr.) Menegh." A minor contradiction is present. In their Latin description, Croasdale and Gronblad state a width of "19 M" for the isthmus of the smaller form, while in the English version, they quote the isthmus as being "9 M" wide. Measurements of f i g . 4 suggest that the 9 Mm figure is the right one, although Prescott e_t a l . (1982) report the isthmus as 16-19 Mm wide. Croasdale and Gronblad are dubious about their i d e n t i f i c a t i o n of this specimen, thinking that i t may be better placed under St. dilatatum Ehrenberg or St. margaritaceum (Ehrenberg) Meneghini. The reason for not naming i t St.  dilatatum is the presence of a c i r c l e of supraisthmial granules 1 48 and the s l i g h t l y irregular .granulation in v e r t i c a l view. The figure of Ralfs (1848; p i . 21 f i g . 8c; P i . B F i g . 11, l e f t ) of St. alternans shows a ring of granules above the isthmus in v e r t i c a l view. Similarly Coesel (1979, p i . 24 f i g . 5) also represents a form of St. alternans with supraisthmial granules. Notwithstanding where i t should be c l a s s i f i e d , f. tetragonum would ce r t a i n l y better be termed only as facies 4 in keeping with Gronblad and Ruzicka's (1959) recommendations. e) St. alternans var. diverqens W. et G.S. West 1902a (p. 177; p i . 21, f i g . 18) PI. C F i g . 3: "Var. minor, apicibus semicellularum concavis, angulis levissime d i l a t a t i s (subcapitatis) sursum l e v i t e r divergentibus; a ve r t i c e v i s i s ut in forma typica sed angulis levissime subcapitatis. "Long. 17 ju; l a t . 17-18 M; l a t . isthm. 5.5 M..." This variety f i r s t found in Ceylon, was l a t e r renamed St.  striolatum var. divergens W. et G.S. West (1912; p. 178, p i . 128 f i g . 6). f) St. alternans var. spinulosum Irenee-Marie and H i l l i a r d 1963 (p. 113; p i . 1, f i g . 3) P i . C F i g . 4 "Varietas separata a typo granulibus mutantis in curtas et tenues spinas longiores ad apices quarumque appendicium... "L. 23-24.5 M; W.(cp) 30-31 M, (sp) 27.5-28 ix; Is. 9-9.6 M." This species i s distinguished by i t s "short and slender thorns 1 49 which are longer at the end of each process". These thorns are grouped around the angles. This pattern of ornamentation d i f f e r s from St. alternans var. alternans. 3. Taxa related to St. alternans The following taxa are closely related to St. alternans St. punctulatum Brebisson ex Ralfs 1848 St. punctulatum var. subproductum W. et G.S. West 1912 St• punctulatum var. striatum W. et G.S. West 1912 a) St. punctulatum Brebisson ex Ralfs 1848 (p. 133; p i . 22, f i g . 1) P i . C F i g . 6: "...segments rough with puncta-like granules, e l l i p t i c , equal; end view with broadly rounded angles and s l i g h t l y concave sides... "Frond larger than that of Staurastrum alternans, rough with minute pearly granules which appear l i k e puncta; segments twice as broad as long, e l l i p t i c ; end view triangular with very blunt angles. " Staurastrum punctulatum may be distinguished from S.  alternans by i t s equal and more turgid segments in the front view, and in an end one by i t s less concave sides. S_^  rugulosum agrees with i t in size and partly in form, but in that species the pearly granules are larger and fewer, and at the angles appear l i k e l i t t l e spines. "Length of frond 1/704 of an inch; breadth 1 / 8 8 1 ; breadth at c o n s t r i c t i o n 1/2270." St. punctulatum i s a common species which was found in many regions of the world. St. alternans is clos e l y related to St. punctulatum. It is on the basis of Ralfs' d i s t i n c t i o n between St. alternans and St. punctulatum that clone HC 205 and 438 as 1 50 well as f i e l d material have been placed under St. alternans. Contrary to Ralfs' concept, some l i t e r a t u r e records do seem to show na r r o w l y - e l l i p t i c semicells and end views with concave sides for c e l l s which are i d e n t i f i e d as St. punctulatum (Scott and Prescott 1958, p i . 14 f i g . 18; 1961, p i . 52 f i g . 14). These could probably be placed in St. alternans, but since the d i s t i n c t i o n between the two species i s poorly defined, i t may be better to wait for a complete reevaluation of these taxa. b) St. punctulatum var. subproductum W. et G.S. West 1912 (p. 182; p i . 127, f i g . 15) P i . C F i g . 7: Syn.: St. punctulatum forma G.S. West 1899 (p. 219) "Cells proportionately wider, l a t e r a l angles of semicells very s l i g h t l y produced; v e r t i c a l view with f a i n t l y convex sides and almost imperceptibly produced angles. "Length 31 y; breadth 31 u; breadth of isthmus 8.5 y." This variety was f i r s t reported as a forma of St. punctulatum from Cambridgeshire (England) by G.S. West and has since been found in many areas of the world. It i s about as long as broad with the angles s l i g h t l y extended or produced, and has s l i g h t l y convex sides in v e r t i c a l view, with almost imperceptibly extended angles. Clones HC 205 and 438 d i f f e r from St.  punctulatum var. subproductum by the less convex apex, the more narrowly e l l i p t i c a l c e l l s , the usually s l i g h t l y concave and occasionally straight sided v e r t i c a l view and the less open sinus (although see P i . 3 F i g . 4). These differences are s u f f i c i e n t to distinguish the two taxa and they are accepted for 151 the t ime b e i n g . c) S t . punctu la tum v a r . s t r i a t u m W. et G .S . West 1912 (p. 186; p i . 128, f i g . 5, 6) P I . C F i g . 8: S y n . : S t . s t r i a t u m (W. et G .S . West) Ruz i cka 1957 (p. 157; p i . 148, f i g . 53-55) " S e m i c e l l s more d i s t i n c t l y rhomboid than in the t y p e ; g r anu l e s most minute , fewer in number, and ar ranged in somewhat d i s t a n t s e r i e s around the a n g l e s . Zygospore e x a c t l y l i k e tha t of v a r . pyqmaeum. "Length 29-31 y; breadth 29-31.5 u) b readth of isthmus 9.5-11.5 ju; d iam. zygosp . w i thout sp ines 36-37 n; w i th sp ines about 67 y . " T h i s taxon i s very s i m i l a r in shape to v a r . subproductum ; however i t d i f f e r s by the s l i g h t l y d i f f e r e n t shape of the s e m i c e l l s and the l e s s numerous and more d i s t a n t rows of g r a n u l e s . The v a r i e t y was r a i s e d to s p e c i e s l e v e l as S t .  s t r i a t u m (W. et G .S . West) Ruz i cka 1957. Ruz icka i l l u s t r a t e s th ree extremes of the range of v a r i a t i o n he observed w i th t h i s t axon , from a c e l l of ova l shape w i th b road l y rounded ang les ( f i g . 53) to a c e l l w i th we l l produced ang les forming shor t p rocesses ( f i g . 55 ) . S i m i l a r v a r i a t i o n was observed in c l o n e s HC 205 and 438 but not to the same e x t e n t . A form wi th w ide ly rounded ang les and s t r a i g h t s i d e s as in R u z i c k a ' s f i g . 53 was observed ( P i . 3 F i g . 6, top s e m i c e l l ) . C e l l s w i th shor t p rocesses were never seen . The most common specimens had e longa ted ang les but the r e d u c t i o n in width from the body of the s e m i c e l l to the ang le was r e l a t i v e l y s l i g h t and g r a d u a l , and the ang les never formed as narrow and e longa ted p rocesses as shown 1 52 by Ruzicka ( f i g . 55). Supraisthmial granules which were observed by Ruzicka, were never seen. d) Discussion St. alternans and St. punctulatum are closely related species which are also very commonly reported in the l i t e r a t u r e . St. punctulatum does comprise a number of v a r i e t i e s which may need to be r e c l a s s i f i e d . A few other species such as St.  striatum are also closely a l l i e d to these taxa. Ruzicka's thorough discussion and inclusion of variation observed in th i s taxon is a f i r s t step toward a more natural c l a s s i f i c a t i o n of thi s group of Staurastrum taxa. The variation in the shape of the c e l l i s often a very gradual process, from rounded angles to short processes, from e l l i p t i c a l to oval to pyramidal semicells. The features d i f f e r e n t i a t i n g these species are often d i f f i c u l t to describe and somewhat variable. Usually the descriptions of the taxa are brief and barely adequate and take l i t t l e account of v a r i a t i o n . This makes i t more d i f f i c u l t for today's taxonomists; they may have only a vague idea of the o r i g i n a l concept and furthermore, are faced with specimens varying only s l i g h t l y from the type species, but which may have been placed in a d i f f e r e n t variety, form or even species. As T e i l i n g (1967) pointed out, sometimes the description of new taxa i s the result of the u n a v a i l a b i l i t y of the large body of l i t e r a t u r e involved. A compilation of publications of desmids taxa or more s p e c i f i c a l l y of Staurastrum taxa such as Nordstedt's would be invaluable, but i t is a major undertaking. 1 53 In this study, clones HC 205 and 438 are described in what is believed to be the o r i g i n a l concept of St. alternans var. alternans and St. punctulatum var. punctulatum. Since Ralf's i l l u s t r a t i o n of St. alternans in pa r t i c u l a r i s very poor, the description and i l l u s t r a t i o n of t h i s taxon by West et a l . (1923) is used to complement Ralfs' description. Table 13 Clonal cultures Clone Source HC 205 J.K. Henry 18-IV-80 438 Munday 16-V-80 CELL DIMENSIONS AND RADIATION OF ST. ALTERNANS (Clonal cultures; N»see Materials and Methods; S.D.=Standard deviation; C V . C o e f f i c i e n t of v a r i a t i o n . F i e l d specimens: N=l; X=presence) Average 35 33 L(csp) (um) Range S.D. 28-38 31-36 1.84 1.00 CV. 6.31 4.66 Average 35 33 l(csp) (urn) Range S.D. CV. 32-38 30-37 1.65 4.44 4.34 13.36 Average 12 11 Is (nm) Range 11-14 11-12 S.D. 0.62 0.49 CV. 6.01 4.26 L / l 1.00 1.01 Radiation (%) 3 100 100 F i e l d material Source L(csp) l(csp) Is L / l Radiation (u.m) (fan) (wm) 3 Munday 16-V-80 39 35 12 1.12 X Munday 20-IX-80 35 36, 39* 12 0.97, 0.89 X Como 27-VI-80 37 36 11 1.03 X Jacobs 8-VIII-80 37 36 11 1.03 X Jacobs 14-VI-79 35 33 9 1.06 X Jacobs 7-VI-80 34 28 10 1.22 X -O Dichotypical c e l l 1 55 Plate 4 St. alternans var. alternans (marker= 10 Mm unless indicated otherwise) 1-6, 9. Clone HC 205, SEM photographs • 1, 2, 4. C e l l s in front view showing the shape and ornamentation of the c e l l s 3. Detailed view of the angles in front view showing the ornamentat ion 5, 6. C e l l s in v e r t i c a l view showing the apical ornamentation 9. Detailed view of the ornamentation 7, 8. Clone HC 205; l i g h t microscope photographs 7. C e l l in front view with delicate granules 8. C e l l in front view with coarse granules. 156 E. STAURASTRUM MURICATUM VAR. MURICATUM St. muricatum Brebisson ex Ralfs 1848 (p. 126; p i . 22, f i g . 2) PI. C F i g . 9: "...segments semiorbicular, rough with conic granules; end view triangular, with convex sides and broadly rounded angles. "Frond deeply constricted at the middle, nearly equal in length and breadth, rough with minute conic granules or spines. End view triangular, i t s sides convex and angles broadly rounded. " Staurastrum mur icatum is larger than S^ hi rsutum, and not hirsute, but rough with stout short granules or spines; in the end view also the sides are more convex. "Length of frond 1/409 of an inch; breadth 1/474." F i r s t described by de Brebisson 1835 (p. 66) as B i n a t e l l a  muricata, St. mur icatum was later tranferred to the genus Staurastrum by de Brebisson in Meneghini 1840 (p. 226). Ralfs (1845) i l l u s t r a t e s both St. hi rsutum ( f i g . 1a, b, c) and St.  muricatum ( f i g . 1d, e) under the name St. muricatum (see PI. C Fig. 10 ) but Ralfs (1848; p. 126, p i . 22 f i g . 2-3) divides St.  mur icatum sensu Ralfs 1845 into two di f f e r e n t taxa, St.  hi rsutum and St. muricatum . St. mur icatum was quite abundant among populations of Sphagnum or aquatic vascular plants in Munday and Lost Lakes. The species has been previously found in Munday and Lost Lakes and 20 records are noted for B r i t i s h Columbia by Stein and Borden (unpublished). St. a r n e l l i i and St. botrophilum were each recorded twice, but not in the lower Fraser Valley. Clones examined: HC 275, 276, 283, 284 from Munday Lake, 1 57 16-V-80; HC 408-411, 414, 415, 417, 418 from Lost Lake, 18-VII-80; HC 492 from Lost Lake, 20-IX-80 (Table 14). St. muricatum grows very well in culture and 26 clonal cultures were successfully established. Of these, 13 clones were measured and observed, nine from Lost Lake and four from Munday Lake. The semicells are e l l i p t i c a l to s u b e l l i p t i c a l to more or less pyramidal in front view ( P i . D F i g . 1, 2). The apex is strongly convex and the angles at the base of the semicells are well rounded. The sinus i s open and acute or s l i g h t l y rounded (PI. D F i g . 1,2). The semicells are ornamented with conical granules disposed in concentric rows around the angles ( P i . 4 F i g . 1, 2). The space between the rows of granules i s r e l a t i v e l y wide. The degree of development of the granulation varies ( PI. 4 F i g . 1-4). This variation i s mostly obvious at the angles: some angles appear rounded while others have a rough outline due to the presence of big conical granules (PI. 4 F i g . 4). The granules were usually coarser in f i e l d than in culture material. In apical view, the sides of the c e l l are s l i g h t l y concave, straight or s l i g h t l y convex. The granules may either cover the whole apex (P i . 4 F i g . 5) or leave a small central area free of granules (PI. 4 F i g . 6). One semicell observed with the SEM microscope from the side of the isthmus (basal view) shows the granulation covering the underside of the angles around the isthmus (PI. 4 F i g . 5). The great majority of the c e l l s were t r i r a d i a t e , but in two 1 58 clones (HC 275, 276), tetraradiate c e l l s made up 1.8 and 2.3% of the c e l l s counted. A l l c e l l s from f i e l d material were t r i r a d i a t e (Table 14). A l l the clones had similar dimensions, but the clones from Munday Lake were s l i g h t l y larger. The L / l r a t i o was just above 1, indicating a c e l l s l i g h t l y longer than wide. F i e l d measurements were in the same range as measurements of clonal cultures (Table 14). 1. Proposed synonyms of St. muricatum var. muricatum St. muricatum var. denudatum Brebisson 1856 St. mur icatum var. denudatum Brebisson 1856 (p. 141): " . . . l a variete denudatum, que j ' a i r e c u e i l l i e pres de Falaise, d i f f e r e du type par sa surface a peine hispide ou chargee d'un p e t i t nombre d'epines tres courtes." The d i s t i n c t i v e c h a r a c t e r i s t i c of thi s variety i s the finer granulation. This feature has been shown to be very variable in clonal cultures and i s not a good taxonomic c h a r a c t e r i s t i c . Thus t h i s variety i s better considered only as a minor variation of St. muricatum var. muricatum. 2. Other i n f r a s p e c i f i c taxa of St. mur icatum The following taxa present c h a r a c t e r i s t i c s which have not been observed in t h i s study and there is no ground not to accept them. Some taxa have already been placed by other authors as synonyms of di f f e r e n t species. 1 59 St. muricatum var. acutum W. West 1890 St. muricatum var. borholmiense Gutwinski 1890 St. muricatum var. a u s t r a l i s Raciborski 1892 St. mur icatum var. subturgescens Schmidle 1893 a) St. mur icatum var. acutum W. West 1890 (p. 294; p i . 5, f i g . 14) PI. C F i g . 11: "Var. spinis brevibus (nec granulis), s e m i c e l l u l i s truncato-pyramidat i s. "Long. 62-70 uj l a t . 48-52 y..." This variety, distinguished by the pyramidal-truncate shape of the semicells and the presence of spines instead of granules, was placed as a synonym of St. pyramidatum W. West 1892a (p. 179). The d i s t i n c t i v e pyramidal shape may j u s t i f y such a move. The type specimen of St. muricatum var. acutum was found in North Wales whereas that of St. pyramidatum was found in West Ireland. b) St. mur icatum var. borholmiense Gutwinski 1890 (p. 71) Synonym: St. muricatum forma Nordstedt 1888 (p. 203; f i g . 19, 20) . Gutwinski did not give a diagnosis or description of th i s taxon, although he referred to Nordstedt's publication. This variety is recognized by West et a l . (1923) as a synonym of St. hirsutum. c) St. mur icatum var. a u s t r a l i s Raciborski 1892 (p. 383, p i . 7 160 f i g . 19) PI. B F i g . 6: "Minor, granulis paucioribus; area suprabasalis et a p i c a l i s glabrae. Long. c e l l . 30 y; l a t . c e l l . 25 M; l a t . isthmi 14 u." This taxon i s smaller than var. mur icatum and has reduced ornamentation and a closed sinus. It appears to be more closely related to St. a r n e l l i i , which is discussed l a t e r , than to St. muricatum. d) St. mur icatum var. subturqescens Schmidle 1893 (p. 554; p i . 28, f i g . 20) P i . C F i g . 12: "48 u longum, 42 u latum, incisura profunda, ampla, intus rotundata, extus ampliata, s e m i c e l l u l i s e l l i p t i c i s , granulatis (granulis acutis parvis in series c i r c u l a r e s d i s p o s i t i s ) e vertice v i s i s triangularibus, angulis late rotundatis, lateribus concavis, medio parva areola t r i a n g u l a r i nuda. "Diese Pflanze nimmt, was Granulation und Zellform anbelangt, die mitte ein zwischen Staur. muricatum Breb. (sic) und Staur. turgescens De Not. Mit der typischen Form selten." The rounded and elongated isthmus shown in the o r i g i n a l figure and the concave sides in apical view, distinguish this taxon from St. muricatum. The regular granulation, more elongated semicell, as well as the shape of the sinus separate i t from St.  turgescens de Notaris. This taxon appears to be more clos e l y related to St. muricatum than to St. turgescens. 3. Uncertain i n f r a s p e c i f i c taxa of St. muricatum The o r i g i n a l publications of the following v a r i e t i e s were 161 not available or the description was so sketchy that no conclusion could be drawn. St. mur icatum var. trapezicum Gutwinski 1890 St. mur icatum var. turgescens Schmidle ? St. mur icatum var. dimidiatum Comere 1901 a) St. muricatum var. trapezicum Gutwinski 1890 (p. 72): "Semicellulae perfecte trapezicae, dorso t r u n c a t e Lg. 42-43 y; l a t . 36 y; i s t h . 12 y; l a t . ap. 22 y." Gutwinski does not provide a picture of his variety. Many trapezoid taxa have been described. Without a more detailed description and an i l l u s t r a t i o n , i t i s d i f f i c u l t to know what alga Gutwinski is referring to. b) St. mur icatum var. turgescens Schmidle ? Cedergren (1926, p. 312) refers to a variety turgescens Schmidle, but probably means var. subturgescens Schmidle 1893. Her bibliography does not c i t e any of Schmidle's publications. No mention of var. turgescens was found in Norstedt (1896, 1908) or in other publications. c) St. muricatum var. dimidiatum Comere 1901 ( p i . 12 f i g . 13) This variety was noted in Nordstedt (1908) but the o r i g i n a l publication was not available. 4. Species related to St. mur icatum The following species are cl o s e l y related to St. mur icatum 1 62 St. hi rsutum (Ehrenberg) Brebisson ex Ralfs 1848 St• botrophilum Wolle 1881 St. trapezicum Boldt 1888 St. a r n e l l i i Boldt 1885 a) St. hi rsutum (Ehrenberg 1834) Brebisson ex Ralfs 1848 (p. 127; p i . 22, f i g . 3) PI. C F i g . 13: "...segments semiorbicular, rough with numerous hair-l i k e spines; end view with three rounded angles and straight or s l i g h t l y convex sides... "Frond variable in size, about equal in length and breadth, deeply constricted at the middle; segments semiorbicular, hirsute rather than spinous; hairs numerous, scattered. End view triangular; the sides straight or s l i g h t l y convex, and the angles broadly rounded. "I have gathered sporangia at Dolgelley and Penzance. They are orbicular, their spines short, and branched at the apex. "The h a i r - l i k e spines are c h a r a c t e r i s t i c of t h i s species. "Length of frond from 1/676 to 1/468 of an inch; breadth from 1/833 to 1/680; breadth at c o n s t r i c t i o n 1/2300; diameter of sporangium from 1/744 to 1/480; length of spine of sporangium 1/2040." St. hi rsutum i s considered by Ralfs (1848) and West e_t a l • (1923; p. 68) to be cl o s e l y related to St. muricatum. West et a l . note that there are intermediate forms between the two species. Although the stoutness of the conical granules varied, no h a i r - l i k e spines, c h a r a c t e r i s t i c of St. hirsutum, were ever observed in culture in the present study. As previously mentioned, granules tended to be more developed in f i e l d 1 63 material. They were usually ca. 1 ym long or less, but short conical spines as long as 2.7 ym were encountered. The wide open sinus and more e l l i p t i c semicells of St. mur icatum also d i f f e r e n t i a t e i t from St. hi rsutum. St. hirsutum appears to be a species d i s t i n c t from St. muricatum. b) St. botrophilum Wolle 1881 (p. 2; p i . 6, f i g . 13) P i . C Fig.15: "St. mediocre, paulo longius quam l a t i u s , d i s t i n c t e granulosum; granulis in series regulares o r d i n a t i s ; a fronte, s e m i c e l l u l i s triangularibus, angulis i n f e r i o r i b u s rotundatis subito in dorsum late truncatis, a lateribus, late e l l i p t i c i s divergentibus, a v e r t i c e , triangularibus. Diam. . 0015"-.0016"... "This form belongs to a class l i k e St. pyqmaeum, Breb., St. punctulatum, Breb., St. ruqulosum, Breb., etc., but is separated by the Cosmarium-1ike, truncate form as seen in front view." St. botrophilum was the object of a good review by Brook and Williamson (1983). These authors are convinced that the Taylor (1935a, p i . 33 f i g . 11, 13) and Croasdale and Gronblad (1964, p i . 18 f i g . 1) records of St. botrophilum represent instead St.  muricatum. However, at least in Taylor's figure, the sinus is d e f i n i t e l y closed, a c h a r a c t e r i s t i c that distinguishes i t from St. mur icatum. St. botrophilum, in Gronblad 1920 (p. 58; p i . 2, f i g . 34, 35), may be better placed in St. mur icatum because of i t s open sinus. Wailes' (1930, f i g . 26) report of St. botrophilum from Mount Ferguson ( B r i t i s h Columbia) does appear to f i t very well the description of that species. 1 64 c) SjU trapezicum Boldt 1888 (p. 35; p i . 2, f i g . 46) PI. C Fi g . 16: "S. fere tarn latum quam longum vel paullo longius, profunde constrictum, sinu profundo acutangulo; semicellulae a fronte visae subtrapezicae, dorso lateribusque levissime concavis, ventre convexo, angulis i n f e r i o r i b u s rotundatis, superioribus obtusangulis, membrana aculeis in seriebus v e r t i c a l i b u s ordinatis instructa; a v e r t i c e visae trigonae, lateribus l e v i t e r r e t u s i s . "Long. 43,2-50,4 u; l a t . 42-43,2 u; l a t . isthmi 15,6-19,8 u; l a t . apic. 16,8 ju." This species is very similar to St. hi rsutum and St. botrophilum, although i t s c e l l s are more depressed and the bases of i t s angles are more elongated. The record of Thomasson (1959) of St. trapezicum from Argentina may be better named St.  muricatum : the c e l l s do show a somewhat pyramidal shape but the bases of the angles are more rounded, not as wide, and the sides of the semicells are more convex. d) St. a r n e l l i i Boldt 1885 (p. 112; p i . 5, f i g . 21) P i . C Fi g . 14: "S. parvum, diametro c i r c i t e r quinta parte longius, profunde constrictum sinu l i n e a r i angusto extremo ampliato; semicellulae trapezicae, e basi recta sursum angustatae, lateribus modice convexis, angulis superioribus obtusis, i n f e r i o r i b u s late rotundatis, margine granulato-dentatae, ad marginem versus granulatae, granulis et a fronte et a vertice radiatim concentriceque d i s p o s i t i s , intima in serie et ad basin semicellularum s i n g u l i s , c e t e r i s in seriebus b i n i s ; e v e r t i c e conspectae triangulares, angulis obtuse rotundatis, lateribus in medio l e v i t e r r e t u s i s . "Long. 36-38,4 u; l a t . 31,2-32,4 u; l a t . isthm. 12 M." 1 65 St. a r n e l l i i i s smaller than St. muricatum, i t s semicells are more truncate-pyramidal in shape and i t s sides, in end view are free of granules. The interpretation of th i s taxon in the l i t e r a t u r e varies. West et a l . (1923; p. 80) note the presence of emarginate granules in the middle of the margin in apical view. Their c e l l s also seem more depressed than in Boldt's i l l u s t r a t i o n of St. a r n e l l i i and have a more widely open sinus. However Forster (1970, p i . 27 f i g . 13) shows e l l i p t i c semicells without emarginate granules. St. a r n e l l i i i s very similar to St. botrophilum but i t i s bigger and has a closed sinus. The strong a f f i n i t y between the two species would seem to j u s t i f y the transfer of St. a r n e l l i i as a variety of St. botrophilum. However a more thorough study of the two species would be necessary before doing so. 5. Conclusion The group of Staurastrum with pyramidal-truncate to s u b e l l i p t i c shaped semicells ornamented with granules to spines comprises a number of d i f f e r e n t species. Other Staurastrum include numerous v a r i e t i e s and forms of one major species. In the present case, there i s not one or two p r i n c i p a l species under which a l l the variations are described v a r i e t i e s or forms, but a group of species. These species can be subdivided into three sub-groups. The f i r s t one contains species with semicells of d e f i n i t e pyramidal-truncate shape and ornamented with granules: St. a r n e l l i i , St.  botrophilum, St. pyramidatum and St. trapezicum. The second 1 66 one has e l l i p t i c semicells with rounded bases, although the more or less f l a t apex does sometimes give them a somewhat pyramidal shape, and are ornamented with granules: St. muricatum, St.  pseudomuricatum Gronblad 1945 ( p i . 29 f i g . 248) and St.  turgescens Notaris 1867 (p. 51 p i . 4 f i g . 43, not seen). The t h i r d group includes semicells of a shape similar to group two but with short spines instead of granules: St. brebi ssoni i and St. hi rsutum. In fact, these are closely related to a whole group of short spined species such as described under St. br e b i s s o n i i . TABLE '14 CELL DIMENSIONS AND RADIATION OF ST. MURICATUM (Clonal cultures; N=see Materials and Methods; CV.= Coefficient of variation. Field specimens: N=l; X=presence; Clonal Clone HC cultures Source Average L(csp) (um) Range S.D. C.V. Average l(csp) (Mm) Range S.D. c v . Average Is (Mm) Range S.D. C.V. L / l Radiation (%) 3 . 4 275 Munday 16-V-80 53 48-58 2.12 4.08 42 38-46 1.89 4.75 17 15-19 0.88 5.30 1.26 97.7 2.3 276 ii it 53 50-57 2.41 4.52 42 37-46 2.11 5.01 17 15-17 0.64 3.88 1.26 98.2 1.8 283 II II 53 46-58 2.78 5.29 42 35-50 2.70 6.49 17 15-19 0.98 ' 5.73 1.27 100.0 — 284 II II 54 48-60 3.28 6.08 43 37-51 2.62 6.08 17 14-18 0.98 5.92 1.25 100.0 — 408 Lost 18-VII-80 51 46-55 2.49 4.92 41 37-45 2.16 5.31 17 17-19 0.62 3.57 1.22 100.0 409 II It 48 38-52 3.53 7.54 39 36-42 1.77 4.59 18 15-20 0.92 5.25 1.21 100.0 — 410 It II 50 45-53 2.43 4.91 40 35-42 1.89 4.78 17 15-18 0.70 4.21 1.25 100.0 — 411 It II 48 43-51 2.27 4.79 40 37-43 1.91 4.83 17 16-19 0.81 4.71 1.19 100.0 — 414 II • II 48 45-53 2.60 5.43 38 33-43 1.76 4.60 18 15-19 0.99 5.61 1.26 100.0 — 415 11 It 49 33-55 4.03 8.25 40 35-47 2.33 5.83 17 14-19 0.97 5.72 1.22 100.0 — 417 II II 46 44-51 1.57 3.39 39 37-41 1.08 2.76 17 16-18 0.67 4.01 1.18 100.0 — 418 II tl 47 40-54 3.30 7.08 38 32-42 1.94 5.16 17 14-19 1.01 6.06 1.24 100.0 — 492 Lost 20-IX-80 50 43-55 3.32 6.58 41 37-46 2.27 5.55 17 14-18 1.08 6.38 1.23 100.0 — continued TABLE lit (cont'd) Field material Source L(csp) (H.m) l(csp) Cum) Munday ll-X-80 51 42 Munday 1-II-81 61 43, 52* Munday 13-111-81 49 44, 38* II II 55 44, 46* ti If 53 48 ti II 51 46, 48* Munday 7-IV-81 51 46, 42* Munday 27-IV-81 51 42, 40* tt II 50 42, 44* II II 51 44, 42* Munday 17-V-81 50 44 II tt 50 42 Munday 9-VI-81 53 48 Munday ll-VIII-81 49 40 *Dichotypical cells Is L / l Radiat 3 16 1.29 X 16 1.41, 1.18 X 16 1.13, 1.30 X 15 1.26, U21 X 17 1.12 X 17 1.13, 1.08 X 15 1.13, 1.23 X 15 1.23, 1.29 X 13 1.18, 1.13 X 15 1.17, 1.23 X 13 1.13 X 15 1.18 X 17 1.12 X 13 1.23 X 1 69 P l a t e 4 St. muricatum var. muricatum SEM photographs 1-5. Clone 414 1. 4. C e l l s viewed from the f r o n t and the apex showing d i f f e r e n c e s in the development of the ornamentation 2. D e t a i l e d view of the granules 3. I s o l a t e d s e m i c e l l showing the isthmus 5. Group of c e l l s , one s e m i c e l l i n b a s a l view on the r i g h t and two c e l l s i n v e r t i c a l view on the l e f t 6. Clone HC 276, group of c e l l s i n v e r t i c a l view showing the a p i c a l ormamentation 1 70 F. STAURASTRUM AVICULA VAR. AVICULA St. avicula Brebisson ex Ralfs 1848 (p. 140; p i . 23, f i g . 11) P i . C F i g . 18: "...segments with a forked spine on each side; each angle, in end view, terminated by a mucro-like spine... "Frond very minute, scarcely rough, the co n s t r i c t i o n producing wide triangular notches; segments having on each side a spine forked l i k e the t a i l of a swallow. End view with three s l i g h t l y i n f l a t e d angles or lobes, which are tipped by a spine. "The forked l a t e r a l spines of the front view mark the spec ies . "Length of frond 1/907 of an inch; breadth 1/948; breadth at co n s t r i c t i o n 1/2403; length of spine 1/4098." St. avicula was found in abundance on the leaves and stems of Nymphaea odorata and intermingled with other algae, in Como Lake. Stein and Borden (unpublished) note 14 records of the species in B r i t i s h Columbia, including Como Lake. Eight records of St. lunatum var. lunatum are given, including Como Lake and one for i t s var. planctonicum from V i c t o r i a Lake. St. denticulatum was recorded twice but not in the lower Fraser Valley. Clones examined: HC 12, 20, 22, 24 from Como Lake, 7-VI-79; HC 58, 60 from Como Lake, 28-V-79; HC 325, 331, 354, 369, 383, 386 from Como Lake, 27-VI-80; HC 420, 424 from Como Lake, 18-VII-80 (Table 15). Thirty-three clones of the species successfully grew in clonal cultures, and 14 of those were observed and measured (Table 15). 171 The semicells in front view appear e l l i p t i c or subtriangular. The apex i s either convex or straight and the sides of the semicells are convex. The sinus i s acute-angled and forms a small notch which opens widely (Pi. 5 F i g . 1-5; PI. E F i g . 1-5, 7-9). The angles are either rounded or more commonly, s l i g h t l y elongated or prolonged into short processes (Pi. 5 F i g . 1, 5; PI. E Fig . 1-5, 7-9), which are divergent and tipped with one to three spines. The t y p i c a l spine arrangement, which according to Ralfs (1848) characterizes the species, is the presence of a forked spine at the angles, the outer spine being longer and divergent, whereas the spine towards the isthmus is shorter and convergent. This pattern is variable and in f i e l d material as well as in clonal cultures, c e l l s have one, two or three spines (P i . E F i g . 1-9). Dichotypical c e l l s with one semicell with one spine and the other with two spines are observed in both culture and f i e l d material (PI. E F i g . 5, 7) and are reported by Croasdale and Gronblad (1964 p. 204; p i . 18, f i g . 12). When only one spine i s present, a stub or a squared angle usually replaces the second spine (Pi. E Fig . 2). A unique bifurcate spine sometimes replaces the two forked spines (Pi. 5 F i g . 4, 5; P i . E F i g . 8). This i s similar to that shown by Croasdale (1957; p i . 5, f i g . 84) for St. avicula forma. The length of the spines varies in f i e l d as well as clonal cultures (1.5-7 Mm) . The apex and sides of the semicells are either smooth or undulated. When the angles are elongated in short processes, 172 they usually are undulated. Depending on the degree of elongation of the angles, i f any, three or four rings of granules surround them. In front or apical view, double verrucae may sometimes be seen on the apex (P i . 5 F i g . 2). According to Brook (1967), they result from the fusion of apical pairs of granules. These double verrucae were of rare occurrence in material in this study and apical granules were not always present. As Brook (1967) points out, however, apical granulation may often be d i f f i c u l t to see, especially when the ornamentation of the c e l l i s obscured by the cytoplasmic content. In apical view, the semicell margins are s l i g h t l y concave, with or without undulated margins ( P i . 5 F i g . 3). When two spines are present at the angles, they often overlap each other so that only one spine i s c l e a r l y v i s i b l e ( P i . E F i g . 6). The c e l l s from f i e l d material were a l l t r i r a d i a t e . In clonal cultures, they were usually t r i r a d i a t e , but tetraradiate and dichotypical c e l l s with one semicell t r i r a d i a t e and the other tetraradiate made up to 4% of the c e l l s counted (Clone HC 354, Table 15). St. avicula var. avicula i s a small species commonly reported in the l i t e r a t u r e and includes many v a r i e t i e s . Many species are also cl o s e l y related. Literature reports, as well as observations of clonal cultures and f i e l d material in the course of the present study, have shown the species to be very variable. The c e l l s may have more or less rounded angles (W. West 1 73 1899, p i . 369 f i g . 10; West et a h 1923, p i . 133 f i g . 8-10; Wailes 1932, f i g . 16; Gronblad 1952, f i g . 32, 33; Croasdale 1965, p i . 8 f i g . 3, 4; Forster 1970, p i . 27 f i g . 5, 6; Coesel 1979, p i . 25 f i g . 4) or angles elongated into short processes (Delponte 1877, p i . 12 f i g . 22-29; f. Schmidle 1898, p i . 2 f i g . 38; Gronblad 1920, f i g . 36-38; Lowe 1923, p i . 4 f i g . 13; Smith 1924b p i . 68 f i g . 8-10; Irenee-Marie 1951, p i . 1 f i g . 4; Ruzicka 1973, p i . 16 f i g . 3; Thomasson 1972, p i . 1 f i g . 8-13). The angles usually bear two spines but, sometimes, they w i l l have only one (Gronblad 1952, f i g . 32, 33; Croasdale 1965, p i . 8 f i g . 3, 4; Thomasson 1972, p i . 1 f i g . 8-13) or occasionally three (Brook 1967, Coesel 1979 p i . 25 f i g . 4). The outline of the c e l l may be smooth (Delponte 1877, p i . 12 f i g . 22-29; Schmidle 1898, p i . 2 f i g . 38; Irenee-Marie 1951, p i . 1 f i g . 4) or more or less denticulated or undulated (G.S. West 1899a, p i . 369 f i g . 10; West et a L 1923, p i . 13 f i g . 8-10; Gronblad 1920, p i . 3 f i g . 36-38; 1952, f i g . 32, 33; Wailes 1932, f i g . 16; Croasdale 1965, p i . 8 f i g . 3, 4; Forster 1970, p i . 27 f i g . 5, 6; Ruzicka 1973, p i . 16 f i g . 3; Thomasson 1972, p i . 1 f i g . 8-13; Coesel 1979, p i . 25 f i g . 4). The granulation may be limited to the angles (Schmidle 1898, p i . 2 f i g . 32; Wailes 1932, f i g . 16; Croasdale 1957, f i g . 84; Coesel 1979, p i . 25 f i g . 4). Apical verrucae are sometimes present (Gronblad 1920, f i g . 36-38; Croasdale 1965, p i . 8 f i g . 3, 4; Ruzicka 1973, p i . 16 f i g . 3). The c e l l s may be e n t i r e l y covered with granules (G.S. West 1899a, p i . 369 f i g . 10; Lowe 1923, p i . 4 f i g . 13; Croasdale 1965, p i . 8 f i g . 3, 4; Forster 1970, 174 p i . 27 f i g . 5, 6). These d i f f e r e n t interpretations of the taxon often integrate c h a r a c t e r i s t i c s of separate species, closely related to St. avicula. Such confusion may arise from the great v a r i a b i l i t y of St. avicula and the naming of species and v a r i e t i e s on morphological variations that are not s i g n i f i c a n t . 1. Proposed synonyms of St. avicula var. avicula  St. avicula var. brevispinum Harvey 1892 St. avicula var. subarcuatum (Wolle) W. et G.S. West 1894 St. avicula var. subarcuatum f. quadrata Irenee-Marie 1957 St. avicula var. verrucosum W. West 1892a a) St. avicula var. brevispinum Harvey 1892 (p. 122; p i . 126, f i g . 13) P i . C F i g . 19: "The type of t h i s species was reported in A r t i c l e I, No. 52, but since then we have found var. brevi spinum , which d i f f e r s from the type by being larger (35yd); the spines shorter and thicker, and the sides of the end view concave. None of the type form were found with t h i s . . . " Harvey's dimensions expressed as yd(?), probably represent ym. This i s very close to the width of 26.7 ym given by Ralfs (1848). Furthermore, a l l i l l u s t r a t i o n s of St. avicula observed have straight or usually concave sides in end view. Ralfs (1848) notes the s l i g h t l y i n f l a t e d angles but not i n f l a t e d sides. Harvey's claim that the concave sides were not seen in the type, disagrees with later i l l u s t r a t i o n s of the type. 175 Harvey's i l l u s t r a t i o n is t o t a l l y inadequate; he does not even show an end view of the alga. West and West (1895a) noted that t h i s taxon can not be accepted. b) St. avicula var. subarcuatum (Wolle) W.et G.S. West 1894 (p. 10) Basionym: St. subarcuatum Wolle 1880 (p. 46; p i . 5, f i g . D) PI. D F i g . 3: Syn.: St. avicula var. verrucosum W. West 1892a (p. 174; p i . 23, f i g . 2) PI. C F i g . 20 Wolle's description i s : "St. mediocre, granulatum, fere tarn longum quam latum, medio profunde constrictum, sinu acutangulo ampliato; s e m i - c e l l u l i s a fronte v i s i s e l l i p t i c i s divergentibus, quasi observe lunatis, granulis in series transversas ordinatis; angulis productis b i f i d i s achrois; dorso papilloso angustato producto, et late truncato; semi-c e l l u l i s a vertice v i s i s triangularibus; angulis rotundatis brevi mucrone imposito; lateribus aut r e c t i s , aut l e v i t e r concavis, in medio p a p i l l i s ornatis, nonnumquam productis b i f i d i s . Diam. .0013"-.0015"..." This taxon was f i r s t c o l l e c t e d in the United States but has since been found in both Europe and North America. The Wests' interpretation of var. subarcuatum i s that: "Punctate and f i n e l y granulate examples of St.  avicula occur more frequently than the glabrous forms. It i s to the roughly granulate form that t h i s variety applies..." Wolle's description of St. subarcuatum did emphazise the presence of subapical or apical "papillae". Furthermore, apical verrucae were occasionally observed in clonal culture. Brook 176 (1967) notes that in the type species, pairs of granules may join to form double verrucae. Flensburg (1967) combines St•  avicula with i t s var. subarcuatum, because "the systematic v a l i d i t y of the variety appears doubtful". Many records of var. subarcuatum agree with the Wests' interpretation in that they are coarsely granulate but bear no verrucae (Taylor 1935a, p i . 34 f i g . 3; Irenee-Marie 1939, p i . 50 f i g . 5, 8; Forster 1970, p i . 27 f i g . 7; Taft and Taft 1971, f i g . 457). The degree of development of the ornamentation is a variable c h a r a c t e r i s t i c which makes a poor taxonomic c r i t e r i o n . Following Flensburg (1967), i t i s proposed that var. subarcuatum be made synonymous with St. avicula var. avicu l a . c) St. avicula var. subarcuatum forma quadrata Irenee-Marie 1957 (p. 153; p i . 1, f i g . 3) P i . D F i g . 7: "L:36-38.6 my; 1:31-32.4 my; I s:11-11.5 my; Ep.:3.4-3.6 my... "Forma separata a varietate subarcuatum speciei S. aviculae forma a p i c a l i quadrangulari." Tetraradiate specimens of St. avicula were occasionally observed in clonal culture. Irenee-Marie's forma quadrata would be better termed facies 4, in keeping with Gronblad and Ruzicka's (1959) recommendations. d) St. avicula var. verrucosum W. West 1892a (p. 174; p i . 23, f i g . 2) PI. C F i g . 20: "Var. membrana d i s t i n c t e verrucosa. 1 77 "Long. 22.5-26 y; l a t . 33~37 y; l a t . isthm. 10 y." This variety is noted as a synonym of var. subarcuatum in West and West (1894a). 2. Taxa closely related to St. avicula It is believed that the following taxa belong to St. avicula• However, since the problem i s very complex and both species are ubiquitous, i t is f e l t that a more thorough study should be carr i e d out before transferring them to a di f f e r e n t taxon. St. dent iculatum (Nageli) Archer in Pritchard 1861 St . lunatum Ralfs 1 848 St. lunatum var. subarmatum W. et G.S. West 1894 St. lunatum var. t r i a n g u l a r i s Borgesen 1894 St. lunatum var. planctonicum W. et G.S. West 1903 St. lunatum var. ovale Gronblad 1942 St. lunatum var. tvaerminneense Gronblad 1942 a) St. denticulatum (Nageli) Archer in Pritchard 1861 (p. 738) Basionym: Phycastrum denticulatum Nageli 1849 (p. 128; p i . 8C, f i g . 3) PI. D F i g . 9: Archer's description follows: "Segments in f.v. s u b e l l i p t i c , inner margin somewhat more turgid than the outer, both undulate or toothed in a scolloped manner with an unequally forked or geminate spine on each side, the upper longer than the lower, the l a t e r a l projections having a series of transverse rows of minute granules; e.v. with three subacute angles the spine appearing as a mucro, sides s l i g h t l y concave at the centre, the margin toothed as 1 78 mentioned before. "L. 1-70 "'; thickness 1-5 »'."= Phycastrum denticulatum (Nag.)G." The main difference between St. avicula and St. denticulatum resides in the presence of granulation only around the angles in the l a t t e r species. Nageli, as pointed out by Brook (1967), also shows the apex of the c e l l to be denticulated, a feature which was not represented by West e_t a l . (1923, p. 38; p i . 133, f i g . 13-15) nor by West and West (1906, p i . 11 f i g . 11), Smith (1924b, p i . 68 f i g . 5-7), Messikommer (1938, p i . 9 f i g . 103). W. West 1890 ( p i . 6, f i g . 27) shows a specimen of St.  dent iculatum with denticulated apex but with the body of the semicell completely covered with granules which are not r e s t r i c t e d to the angles of the semicells. It has been noted e a r l i e r that in some published figures of St. avicula as well as the o r i g i n a l i l l u s t r a t i o n of St. subarcuatum, c e l l s have granules only at the angles. Brook (1967) points out that apical ornamentation i s often a d i f f i c u l t feature to distinguish and p a r t i c u l a r l y i f c e l l protoplasm is present. This was c e r t a i n l y true for the present study where some c e l l s did not appear to have any apical ornamentation, whereas others did. In any event, Nageli's o r i g i n a l figure shows apical ornamentation. Because of the divergence between the o r i g i n a l and subsequent publications, and the close re l a t i o n s h i p between St. avicula and St. denticulatum, I agree with Brook (1967) that the species dent iculatum should be considered only as a form of St. avicula. 179 b) lunatum Ralfs 1848 (p. 124; p i . 34, f i g . 12) PI. D F i g . 10: "...frond rough with puncta-like granules; segments externally lunate, with an awn at each angle; end view with three i n f l a t e d awned lobes... "This species resembles in figure Staurastrum dejectum , but i t is larger. Frond deeply constricted at the middle; segments semilunate, the convex margins united, the outer margin rough with minute granules and truncate, each angle tipped by an awn or mucro which i s directed obliquely outwards. End view three-lobed, the lobes i n f l a t e d , obtuse and awned. "Its rough frond distinguishes Staurastrum lunatum from a l l the preceeding species, and the i n f l a t e d awned lobes of i t s end view from a l l the following ones. "Length of frond 1/856 of an inch; breadth 1/686; breadth at c o n s t r i c t i o n 1/2336; length of spine 1/4098." St. lunatum i s a common species which has been reported in many regions of the world. It is another close r e l a t i v e to St.  avicula, the main difference between them being the presence of only one spine at each angle in St. lunatum. Croasdale and Gronblad (1964; p. 204) found dichotypical c e l l s with one semicell resembling St. avicula and the other St. lunatum ; another c e l l of St. lunatum had one angle tipped with two spines with the three other angles bearing only one spine. This phenomenon was observed frequently in HC clones as well as in f i e l d material. A l l combinations were seen. Sometimes the two angles of one semicell each had two spines, whereas the two angles of the corresponding semicell had only one spine each. On other c e l l s , one angle of the semicell bore one spine but the second angle of the same semicell had two spines. C e l l s with 180 only one angle or with the four angles bearing one spine were also observed. Based on the variation seen in the drawings presented on P i . E F i g . 1-9, i t seems that there is l i t t l e d i f f e r e n t i a t i o n between St. avicula and St. lunatum. The number of spines at the angle, does not appear to be a stable taxonomic c h a r a c t e r i s t i c . In clonal and f i e l d material studied here, the predominant form had two spines at each angle, although the one spine variation was not uncommon. Reports of St. lunatum or of i t s v a r i e t i e s are usually represented with a single angular spine at each angle. Gronblad (1960, p. 47) states that the main difference between a specimen he named St. lunatum var. messikommeri Gronblad 1948 and St. avicula var. exornatum, is the constant presence of one spine at each angle in the former. It s t i l l seems that the number of spines at the angles i s a feature which i s too variable to d i f f e r e n t i a t e between two species; St. lunatum may be better considered as a form of St.  av i c u l a . c) I n f r a s p e c i f i c taxa of St. lunatum i) St. lunatum var. subarmatum W. et G.S. West 1894 (p. 10; p i . 2, f i g . 47) PI. D F i g . 11: "Var. arigulis attenuatis in spinam mucronatam. "Long. 30 M; l a t . c. mucr. 33 M; l a t . isthm. 11.5 M." This taxon appears to be rare. The length of the spines, and thus the presence of a mucro instead of a spine, i s too variable 181 a feature upon which to base a variety. West and West (1912) consider this taxon as synonymous with St. granulosum (Ehrenberg) Ralfs. It may be better to establish a forma rather than a variety for th i s minor d i s t i n c t i o n . i i ) St. lunatum var. t r i a n g u l a r i s Borgesen 1894 (p. 29; p i . 2, f i g . 24) PI. D F i g . 12: "Semicellulae a fronte visae fere triangulares dorso paene recto truncato, aculeis r e c t i s . C e l l u l a minor. "Long. = 20u= l a t . s i n . acul.; l a t . isthm.= 9.5M; long. acul.= 3u.. This taxon was f i r s t recorded from Greenland. With i t s very wide open rounded sinus, and triangular shaped semicells with straight apex and sides, i t i s very d i f f e r e n t from St. lunatum. In his text, Borgesen uses the nomenclatural rank of variety but in the legend to his plate, he uses forma t r i a n g u l a r i s instead. This taxon may be better placed in another species. i i i ) St. lunatum var. planctonicum W. et G.S. West 1903 (p. 546; p i . 16 f i g . 11, 12) P i . D F i g . 13: "Var. paullo major et l a t i o r , angulis semicellularum acutioribus, spinis minoribus; semicellulae a vertice visae cum lateribus latissime r e t u s i s . "Long. 40-44 u; l a t . sine spin. 42-50 M; long. spin. 3-5.5 u; l a t . isthm. 14.5-16 M..." This variety was f i r s t found in Scotland and has since been reported from both Europe and North America. With i t s acutely produced diverging angles, i t is not unlike some specimens 182 observed in the present study (see PI. E Fig.5, 7). The Wests indicate that the spines of var. planctonicum are shorter than in the type. A comparison of some measurements may be of interest: Length of spines: St. lunatum var. planctonicum in West and West 1903 (p. 546) : 3-5.5 nm St. lunatum in West et a l . 1923 (p. 30): 3.5-12 nm St. lunatum in Ralfs 1848 (p. 124): 1/4098" or ca. 6 ym St. avicula-lunatum P i . E F i g . 7: 3.5, 5.4 /xm. Thus, the range of variation in the length of the spine i s wider in West et a l . (1923) than in West and West (1903) or Ralfs' o r i g i n a l description of St. lunatum. Although Smith's (1924b; p i . 68, f i g . 11-13) figures show the elongated diverging angles of the variety planctonicum, Irenee-Marie (1939; p i . 50 f i g . 6) and Coesel (1979, p i . 25 f i g . 1, 2) do not stress this important feature. Gronblad (1960; f i g . 208-212) shows d i f f e r e n t formae of St. lunatum, among which there are some algae with almost rounded or s l i g h t l y pointed angles ( f i g . 211), and others with one ( f i g . 208) or two ( f i g . 210) short divergent spinules or with elongated angles ( f i g . 212) comparable to var. planctonicum (see PI. D F i g . 14). His observations and my study emphasize the close a f f i n i t y between var. lunatum and var. planctonicum. It i s proposed that var. planctonicum be considered only as a minor variation of St. lunatum. 183 iv) St. lunatum var. ovale Gronblad 1942 (p. 40; p i . 5, f i g . 1, 2) PI. D F i g . 15: "Cellulae habitu ut in var. tvaermineense Gronbl. A vertice visae ovales. Massa chlorophyllacea c e n t r a l i s in utraque semicellula nucleis amylaceis s i n g u l i s et laminis radiantibus. 6. Long. 32 c. spin. l a t . 57 s. spin. l a t . 31 crass. 18 i s t . 9 y." Gronblad (1952) expresses the doubt that t h i s variety, f i r s t found in the Swedish Lappland, belongs to St. lunatum, and states that i t i s a temporary arrangement. In his specimens from Greenland (Gronblad 1952), the angles often have two tiny spines at each angle instead of one mucro. The c h a r a c t e r i s t i c oval shape of the c e l l with almost p a r a l l e l spinules is f a i r l y d i s t i n c t from St. lunatum which has e l l i p t i c or triangular semicells with straight or s l i g h t l y convex apices and strongly convex sides in front view, the divergent spines being directed upward. In accordance with Gronblad (1952), t h i s variety should be c l a s s i f i e d in a d i f f e r e n t species. v) St. lunatum var. tvaerminneense Gronblad 1942 (p. 42). "Syn. St. lunatum Ralfs forma Gronbl., Tvarminne p. 266 F i g . 43-44 (long. 23 l a t . 30 i s t . 9 y) . D i f f e r t a typo granulis in seriebus paucioribus, numero 8, d i s p o s i t i s . Sinu introrsum l i n e a r i extrorsum d i l a t a t a , angulis basalibus semicellularum valde rotundat i s." No figure was provided in Gronblad (1942) and the figure referred to on the f i r s t l i n e of the description was not a v a i l a b l e . No record of the variety was found in later publications, and the description does not stress any feature 184 which would make this variety obviously d i f f e r e n t from St.  lunatum. 3. Other i n f r a s p e c i f i c taxa of St. avicula The following taxa have c h a r a c t e r i s t i c s which have not been observed in this study and no conclusions can be drawn. Some have been placed as synonyms of other taxa by d i f f e r e n t authors. St. avicula var. ac i c u l i ferum W. West 1889 St. avicula var. inerme Irenee-Marie 1949 a) St. avicula var. aciculiferum W. West 1889 (p. 293; p i . 291, f i g . 12) PI. D F i g . 4 Syn.: St. aciculiferum (W. West) Andersson 1890 (p. 11; p l . 1, f i g . 4). This rare variety is considered a separate species, St.  aciculiferum, by Andersson. At least two new v a r i e t i e s of St. ac i c u l i ferum have been named, var. pulchrum (W. et G.S. West) Forster 1970 (p. 332; p l . 27, f i g . 21) and var. b u r k a r t i i T e l l 1980 (p. 146 p l . 1 f i g . 10) The elongated processes and subapical spines i l l u s t r a t e d by W. West were not seen in the material observed in this study. Andersson's interpretation of th i s taxon as a d i s t i n c t species, appears to have been endorsed by modern authors who named new v a r i e t i e s of the species and I agree with their interpretation. b) St. avicula var. inerme Irenee-Marie 1949a (p. 102; p l . 1, f i g . 1) P l . C F i g . 17: 185 "...Planta minutissima cujus corpus simillinum typicae s p e c i e i , sed dimidio minor et cujus anguli in inermis processibus producunt. Optimum est reli g a r e hanc varietatem ad speciem Aviculam tanquam varietas inermi s." With i t s small size and the lack of spines at i t s angles, this variety, f i r s t reported in the area around Trois-Rivieres (Quebec, Canada), i s easily distinguished from St. avicula var. avicula. It appears to have been reported only from the Tro i s -Rivieres area (Irenee-Marie 1949a, 1957). 4. Uncertain v a r i e t i e s of St. avicula The o r i g i n a l publications of the following taxa were not available and no conclusions can be drawn. St. avicula var. rotundatum W. et G.S. West 1907 St. avicula var. exornatum Messikommer 1929 a) St. avicula var. rotundatum W. et G.S. West 1907 (p. 214; p l . 15, fig.25) P l . D Fig.5: This alga was f i r s t c o l l e c t e d in Burma. It appears to be rare. The rounded angles, open sinus and granules covering most of the c e l l , seem to be the most important feature of this alga. A l l of these c h a r a c t e r i s t i c s were seen in published reports of St. avicula (see for example the very similar alga i l l u s t r a t e d by Wailes 1932, f i g . 16, and which d i f f e r s mostly by the more convex apex, straighter sides of the semicell and granules grouped around the angles). C e l l s with rounded angles were found in clonal cultures ( P l . E F i g . 4, 8). This may be a 186 synonym of St. avicula but no conclusion can be drawn without consulting the o r i g i n a l publication. b) St. avicula var. exornatum Messikommer 1929 ( p i . 1, f i g . 15) The o r i g i n a l publication of th i s variety, which seems to be rare, was not available; a figure given by Coesel (1979, p i . 25 f i g . 5, 6) is shown on P i . D Fig . 6. According to Gronblad 1948 (p. 417), th i s variety may be a synonym of St. avicula var. subarcuatum (Wolle) W. et G.S. West, but consultation of the o r i g i n a l description i s necessary before any conclusion can be made. 5. Related species to St• avicula The following species are similar to St. avicula var. avicula St. caronense Irenee-Marie 1949a St. qranulosum (Ehrenberg) Ralfs 1848 a) St. caronense Irenee-Marie 1949a (p. 103; pi.1, f i g . 3) Pl.D F i g . 8: "... L.(sp): 27.3-27.5; (cp) : 35.4-36.5; l . ( s p ) : 25.5-25.8; (cp): 35.4-36.2; Is.: 10.8-11... C e l l u l a parva constrictione profunda, sinibus apertissimis et acutis ad apicem. Semicellulae fere semi-circulares arcu ad isthmum verso, diametris apices e f f i c i e n t i b u s . Laterales anguli in longis processibus l e v i t e r granulosis producti et in 2 vel 3 divergentibus v a l i d i s spinis d e s i t i . Ab spicale v i s a S t e l l a cum 4 processibus 3 vel 4 granulorum annulis ornatis, cujus l e v i t e r c a p i t a t i apices 2 spinis terminantur prominentibus a l t e r a super alteram (saepissime 3 187 triangulatim d i s p o s i t i s ) . Margines l e v i t e r undulatae praeter in mediis qui retusi sunt. Quaeque semicellula 4 parie alibus chloroplastibus ornata, reliquentes vacuum inter se in centro, ab polo ad polum visum ut licidum punctum a vertice visum." This taxon was f i r s t reported from the Trois-Rivieres area (Quebec, Canada), but has not been recorded since. This small species has much in common with St. avicula. It is similar in shape, the angles are produced and tipped with two or three spines and the sinus is acute and widely open; i t i s tetraradiate with a straight apex and granulation r e s t r i c t e d to the angles. A l l these c h a r a c t e r i s t i c s have been observed in published i l l u s t r a t i o n s or clonal cultures of St. a v i c u l a . It is not clear why Irenee-Marie did not stress the resemblance between his species and St. avicula. The description of St.  caronense does not state any strong feature which j u s t i f i e s the creation of a new species but i t s constant tetraradiation seems to d i s t i n g u i s h i t from the mostly t r i r a d i a t e St. avicula var. avicula. Observation of the material from the type l o c a l i t y would be advised before placing t h i s taxon as an i n f r a s p e c i f i c taxon or synonym of St. avicula var. a v i c u l a . b) St. granulosum (Ehrenberg 1839; p. 51, 56 p l . 1 f i g . 12) Ralfs 1848 (p. 217) Syn.: St. lunatum var. subarmatum W. et G.S. West 1894 St. granulosum i s a small punctate alga of shape similar to St. avicula but with angles having only " a mucro (or very minute spine)" (West and West 1912; p. 189, p l . 128 f i g . 10-12). West and West (1912) see St. lunatum var. subarmatum as a 1 88 synonym of this species. This alga was f i r s t described by Ehrenberg (1839) under the name Desmidium granulosum. Ralfs 1848 (p. 217) transferred i t to the genus Staurastrum but did not give any description or figure, noting only that " th i s species is known to me only by name." Ehrenberg's publication was not available. From other i l l u s t r a t i o n s of the species, i t appears to be closely related to St. avicula. One very interesting record is by Taft and Taft (1971, f i g . 468) where the four angles each bear two minute spines instead of one. The Taft and Taft record would be better i d e n t i f i e d as St. avicula, because of the presence of two spines and since the spines have been shown to vary in length in St. avicula. Before drawing any conclusion about St. dent iculatum, a more thorough investigation and observation of the o r i g i n a l publication is necessary. 6. Conclusion In conclusion, the group St. avicula-dent iculaturn-1unatum- granulosum comprises many species and v a r i e t i e s , among which intermediate forms are known. ^  The number of spines at the angles, the ornamentation or the shape of the angles have proved to be variable in the Como Lake populations and in clonal cultures and j u s t i f i e s the need for a very thorough and c r i t i c a l reevaluation of the whole taxonomic complex. TABLE 15 CELL DIMENSIONS AND RADIATION OF SJ. AVICULA (Clonal cultures; N=see Materials and Methoas; s.D.=Standard deviation; C.V.=Coefficient of variation. Field specimens: N - l ; X=presence) Clonal cultures Clone Source HC L(csp) (»m) l(csp) (Mm) Is (urn) L / l Radiation (%) Average Range S.D. C V . Average Range S.D. C V , Average Range S.D. C V . 3 12 Como 7-VI-79 25 22-28 1.35 5.54 28 24-34 2.31 8.40 10 8-11 0.79 8.25 0.89 98.8 — i:2 20 tt II 24 23-27 1.27 5.23 25 22-29 1.82 7.76 10 9-12 0.65 6.56 0.88 100.0 — — 22 it' It 25 -20-28 2.04 8.27 27 22-32 2.68 9.99 10 9-12 0.89 8.63 0.92 98.4 1.6 — 24 it tl 23 19-27 1.95 8.49 26 19-30 2.81 10.90 9 6-12 1.40 15.19 0.89 98.4 1.6 — 58 Como 28-V-79 25 22-30 1.78 7.21 26 22-33 2.87 10.88 10 7-12 1.00 9.96 0.93 98.4 1.6 — 60 it II 24 21-27 1.84 7.74 26 21-31 3.13 12.12 11 9-12 0.79 7.34 0.92 100.0 — — 325 Como 27-VI-80 25 22-31 1.87 7.37 26 22-32 2.37 8.08 11 9-14 0.88 8.38 0.97 97.7 — 23 331 it tl 25 22-33 2.31 9.32 28 22-41 3.85 13.92 10 8-16 1.61 14.79 0.87 98.6 1.4 — 354 II II 24 22-27 1.80 7.53 25 22-31 2.55 10.12 10 7-13 0.96 9.32 0.85 95.9 0.7 3A 369 it 11 26 23-28 1.48 7.80 28 24-32 2.11 7.60 11 10-12 0.83 7.35 0.81 99.5 — 0.5 383 II M 25 22-29 1.83 7.64 27 23-32 3.17 11.87 11 9-12 0.87 8.10 0.86 98.2 1.8 — 386 it II 27 24-31 1.71 6.36 28 23-34 2.66 8.42 12 10-15 1.03 8.48 0.86 98.3 1.7 — 420 Como 18-VI-80 25 22-28 1.84 7.34 28 23-34 3.05 11.05 10 8-11 0.74 7.36 0.81 98.6 0.5 05 424 it it 25 23-29 1.30 5.17 27 22-34 2.61 9.82 11 9-13 0.96 8.95 0.95 98.0 — 2D 00 VO continued Field material Source Como 16-V-79 M II It It Como 28-V-79 Como 7-VI-79 Como 14-VI-79 Como 28-VI-79 Como 6-VII-79 Como 26-VIII-79 Como l-VIII-79 I I I I Como 15-VIII-79 *Dichotypical cells L(cap) Cm) 28 21 17 21 26 26 26 18 20 24 23 25 27 18 28 23 20 21 TABLE 15 (cont'd) L(ssp) («m) 21 19 21 20 20 17 l(csp) (um) 24 28 28, 27* 25 30 29 30 28, 32* 30 30, 25* 29 32, 32* 27 26 32 32 23 34 l(ssp) (urn) 23 11 Is (mn) 5 7 7 9 Sp L / l Radiation 3 1.15 X 0.74 X 0.61, 0.63 X 0.82 X 0.88 X 0.89 X 0.88 X 0.64, 0.57 X 0.67 X 3, 4, 2, 5, 0.84, 0.96 X 6, 4, 5. 0.78 X 0.78, 0.80 X 1.00 X 0.69 X 0.90 X 0.71 X 0.88 X 0.62 X vo O continued TABLE 15 (cont'd) Field material Source L(csp) L(ssp) Kcsp) l(ssp) Is L / l Radiation (m) (Mm) (um) (Mm) (Hm> 3 Como 23-11-80 27 ~ 36 — 10 0.74 X Como 27-VI-80 22 19 L ; 31 — 8 0.70 X 11 It 24 20 31 — 9 0.77 X Como 18-VII-80 27 21 32 25 9 0.84 X II II 25 21 31 — 8 0.80 X M II 25 19 29, 30* — 7 0.86, 0.82 X Como 8-VIII-80 21, 23 19 28, 31* — 7 0.74, 0.73 X i i n 21 19 28, 32* — 8 0.74, 0.65 X II II 23 20 25 21 8 0.91 X Como l-XI-80 26 23 31 25 8 0.83 X Como 7-IV-81 32 26 38 28 9 0.83 X Como 28-VIII-81 24 21 29 — 7 0.82 X II II 23 21 29 — 7 0.79 X it II 22 — 27 — 8 0.81 X it II 26 22 30 8 0.86 X *Dichotypical cells 1 92 P l a t e 5 S t . a v i c u l a v a r . a v i c u l a SEM photographs 1. C lone HC 24, c e l l in f r o n t view 2, 3. C lone HC 22 2. C e l l viewed from the f r o n t and the apex showing the double a p i c a l ve r rucae 3. I s o l a t e d s e m i c e l l in ba sa l v iew. 4. C lone HC 20, d e t a i l of a c e l l in f r on t view showing a b i f u r c a t e sp ine 5. C lone HC 24, c e l l in f r o n t view showing a b i f u r c a t e sp ine (upper r i g h t ang le ) and a fo rked sp ine (lower r i g h t ang le ) U3iA 1 93 G. STAURASTRUM PROBOSCIDEUM FORMA MINOR INCLUDING ST. PROBOSCIDEUM VAR. PROBOSCIDEUM St. proboscideum (Ralfs) Archer f. minor (Schmidle 1898, p. 60 p l . 3 f i g . 16) Prescott, Bicudo et Vinyard 1982 (p. 285; p l . 439, f i g . 4) Basionym: St. borgeanum Schmidle f. minor Schmidle 1898 (p. 60; p l . 3, f i g . 16) P l . E F i g . 10: "Cellulae minores, 20 u longae et latae, aut 37-32 u latae, 32-29 u longae eadem granulatione (supra isthmum interdum binis seriebus granulorum), e vertice plerumque vix contortae... "Die Exemplare der forma minor nahern sich dem St. polymorphum." There are only two records of St. probosc ideum var. probosc ideum in B r i t i s h Columbia, both from the Peace River area (Stein and Borden, unpublished). The similar species, St.  borgeanum, has never been recorded. However, the variable and close l y related St. polymorphum var. polymorphum has been reported 38 times, including from Lost, Munday and Como Lakes. The s i m i l a r i t y between the three taxa w i l l be discussed l a t e r . Clones examined: HC 2, 4, 6, 62 from Como Lake, 28-V-79; HC 242 from Como Lake 26-IV-80; HC 278 from Como Lake, 16-V-80; HC 333, 334, 362, 363, 370, 378, 381, 388, 389 from Como Lake, 27-VI-80; HC 422 from Como Lake, 18-VII-80; HC 293, 295, 301 from Munday Lake, 7-VI-80; HC 433 from the VanDusen Garden, 28-VII-80 (Table 16). F i f t y - f i v e of the clones iso l a t e d grew successfully and 20 were measured and observed, 17 from Como Lake, three from Munday 1 94 Lake and one from the VanDusen Botanical Garden. In front view, the c e l l has a cup-shaped acute-angled sinus which opens widely. The base of the semicell usually has a ring of supraisthmial granules. The c e l l s are s l i g h t l y wider than long and the L / l r a t i o in f i e l d specimens i s usually s l i g h t l y lower than in clonal cultures (Table 16), indicating possibly shorter processes in cultures. The apex i s convex and usually bears more or less prominent double verrucae or granules (PI. 6 F i g . 2, 3, 5-7). Granules are seen on the front face of the semicell ( P i . 6 F i g . 1). The angles are extended into processes of varying length (Pi. 6 Fig . 1-4) which are usually tipped with four minute spines. The processes, which are either p a r a l l e l or convergent, are ornamented by concentric rings of small conical granules. In apical view, the sides of the semicell are s l i g h t l y concave and lined with small conical granules ( P i . 6 F i g . 5-7). The centre of the apex i s free of ornamentation but lined by double verrucae ( P i . 6 Fig . 5, 7). On some c e l l s , double verrucae are absent and replaced by simple granules (PI. 6 Fig . 6). Conical granules run down on the front of the semicell from the most central verrucae or granules (Pi. 6 F i g . 5-7). One dichotypical specimen was observed in f i e l d material whereas in clonal cultures as much as 5.0% of the c e l l s counted were t r i - t e t r a r a d i a t e (clone HC 278). Only t r i - and tetraradiate semicells were observed in f i e l d material. In clonal cultures, t r i - , t e t r a - or pentaradiate specimens were present (Table 16). 195 St. probosc ideum f. minor i s considerably smaller than St.  borgeanum (L = 45; 1 = 53 ym) or St. proboscideum (L = 46; 1 = 41; Is = 11 ym). The size v a r i a t i o n in f i e l d material from the present study i s L = 21-31, Hep) = 22-41 ym. In clonal culture i t i s , L = 19-34, Kcp) = 20-37 ym. Since t h i s range d i f f e r s largely from either St. borgeanum var. borgeanum or St. probosc ideum var. proboscideum, forma minor i s retained as a good forma. The transfer of St. borgeanum to St.  probosc ideum w i l l be discussed l a t e r . Prescott et a l . (1982) changed the name of the i n f r a s p e c i f i c epithet from minor to minus. This does not appear warranted since minor i s the comparative of parvus and an a d j e c t i v a l form. Thus, the o r i g i n a l epithet is kept in the present study. 1. Proposed synonym of St. probosc ideum f. minor  St. borgeanum var. parvum Messikommer 1949 St. borgeanum var. parvum Messikommer 1949 (p. 247; p i . 1, f i g . 17) PI. F F i g . 7: "Lge. 30 y, Br. 37 y, Isthm. 12 y." This taxon was created after forma minor, but i t also represents small forms of St. borgeanum. Messikommer may simply not have been aware of the existence of forma minor Schmidle 1898. St. proboscideum (Brebisson ex Ralfs 1848) Archer in Pritchard 1861 (p. 742) 196 Basionym: St. asperum var. probosc ideum de Brebisson ex Ralfs 1848 (p. 139; p l . 22, f i g . 6, p l . 23 f i g . 12) P l . E F i g . 12: Ralfs description follows: " S^ asperum (Breb.); segments e l l i p t i c or somewhat cuneiform, rough with minute spines, which on the outer margin are usually d i l a t e d at the end or forked. "a . Angles in end view rounded. "/3 . proboscideum, Breb.; angles in end view prolonged into short rays terminated by minute spines... "Frond comparatively large, rough with minute acute granules or spines; segments s l i g h t l y tapering on the inner side, so that their figure is somewhat cuneate, and the co n s t r i c t i o n forms a wide notch on each side. The outer margin i s flattened, and i t s spines are usually more evident than the rest, and are also in general s l i g h t l y forked. In a . the l a t e r a l margins are broadly rounded, but in |3 . they extend into a process about as long as broad and tipped with a few acute spines, which are larger than those on the segment i t s e l f . The end view, in which the sides are nearly straight, has the angles in a . rounded, but in (1 . terminated by short rays. "The sporangia, which I have gathered at Penzance, are orbicular, and their spines are twice branched at the apex. "The form of the segments distinguishes Staurastrum  asperum from a l l states of S_j_ muricatum. S.  punctulatum i s smaller, and i t s granules are more l i k e puncta than spines. In S_^  rugulosum the segments in the front view are e l l i p t i c , not tapering at the junction, and i t s spine-like granules are confined to the angles. "Length of frond 1/555 of an inch; breadth 1/615; breadth at co n s t r i c t i o n 1/2403; diameter of sporangium 1/519; length of spines 1/2040..." The f i r s t v a l i d publication of St. probosc ideum was by Ralfs 1848 under the name St. asperum var. probosc ideum. 1 97 Unfortunately as is true for many of Ralfs' i l l u s t r a t i o n s , the figures are very poor and do not stress the d i s t i n c t i v e features of the species. Archer (in Pritchard 1861) later gave the name St. probosc ideum to thi s taxon. St. asperum var. asperum has been recorded only a few times and i t s v a l i d i t y i s uncertain. 2. Synonyms of St. probosc ideum var. probosc ideum  St. borgeanum Schmidle 1898 St. probosc ideum var. productum Messikommer 1942 a) St. borgeanum Schmidle 1898 (p. 60; p i . 3, f i g . 7) P i . E Fig . 11: "Cellulae submagnae, 45 M longae, 53 M latae profunde constrictae, constrictura ampla, intus rotunda, extus ampliata; semicellulae e fronte subcuneatae, lateribus valde divergentibus, concavis et in processus 2 granulatos, apice truncatos et granulato-dentatos exeuntibus, apice late rotundato. Membrana a p i c i s glabra, area glabra undique serie processuum bifurcatorum parvorum circumdata, latera et basis processuum (e fronte) in series rectas v e r t i c a l e s granulatae (granula processus bifurcatos a p i c i s non n i s i ad extremos angulos attingentia) , supra isthmum series h o r i z o n t a l i s granulorum. Cellulae e vertice quadrangulares, raro triangulares, lateribus concavis, acute granulatis, medio in apice glabrae, r a d i i s subcontortis... "Unsere Algae steht zwischen St. hexacerum und cyrtocerum ; zu ihr gehort wohl a ls einfachere Form St. hexacerum var. ornatum Borge, I.e. Sie steht ausserdem dem St. basidentatum Borge nahe, unterscheidet sich aber durch die Granulation und Grosse. St. dubium West und St. probosc ideum Archer sind ebenfalls nahe stehende Arten." St. borgeanum i s considered synonymous with by Nordstedt 1908 (p. 32) and West et a l . St. probosc ideum 1923 (p. 129-31). 198 Gronblad (1926) later rejected t h i s synonymy and recognized St.  borgeanum as a good species. Cedergren (1932) did suggest establishing a variety borgeanum of St. probosc ideum for i t . Ralfs' drawings are too sketchy to be used as type species as stressed by Thomasson (1957). The figure in West et a l . (1923; pl 143, f i g . 9) proposed by Gronblad as the type figure for St. probosc ideum does not resemble Ralfs' description. However, reading Gronblad's text, i t appears obvious that he was ref e r r i n g to St. cyrtocerum ( sensu West et a l . 1923, p l . 149 f i g . 9). Thomasson r e c t i f i e d Gronblad's error. Plate 143 f i g . 9 is i d e n t i f i e d as St. crenulatum and has very short processes not tipped with spines. The c e l l i l l u s t r a t e d on plate 149 f i g . 9 has converging processes contrary to Ralfs' i l l u s t r a t i o n . It also d i f f e r s in dimensions: St. cyrtocerum (West et a l • 1923): L: 23-29; l ( c p ) : 33-60; Is: 8-11 ym. St. asperum (Ralfs 1848): L:45.8; 1:41.3; Is: 10.6 um. These dimensions and the comparison between length and width show that West et a_l. ' s taxon i s not as long as but i s wider, than Ralfs'. However, while describing two d i s t i n c t taxa, that is St. asperum with rounded angles and i t s var. probosc ideum with short processes, Ralfs gave only one set of dimensions. These dimensions, which point to a plant almost equal in length and width, may be misleading. I think that they refer to the specimen with rounded angles, that i s St. asperum, rather than 199 to var. probdscideum. Furthermore, Ralfs' i l l u s t r a t i o n s are very sketchy and the front view gives no d e t a i l s of the c e l l ornamentation. Gronblad's decision to pair p l . 149 f i g . 9 of West et al_j_ (1923) with Ralfs' (1848) p l . 123 f i g . 12 b and c, appears mostly based on the resemblance between the v e r t i c a l views of those two c e l l s . I feel that this decision is based on very poor information and is too subjective. The ICBN (1978, p. 75) states that the choice made by the o r i g i n a l author i s f i n a l (see St. polymorphum). While noting that he recognizes St. borgeanum as a good species that d i f f e r s from St. probosc ideum, Gronblad (1926) does not state those differences. Thomasson (1957) thoroughly discusses St. borgeanum and related species although he witholds his conclusion on St. probosc ideum. Prescott et a l . (1982) propose that St. borgeanum be reduced to synonymy with St. probosc ideum and I agree with them. This is based on the variation observed among HC clones, p a r t i c u l a r l y in the length and the stoutness of the processes (Pl . 6 F i g . 1-4), degree of development of the ornamentation, including the often indistinguishable supraisthmial ring of granules (represented in Schmidle 1898 for St. borgeanum ) and lack of unmistakable i l l u s t r a t i o n of St. probosc ideum. St.  probosc ideum encompasses species with short stout processes intermediate between i t s var. compactum Gronblad 1927 (p. 26 f i g . 89-90), discussed l a t e r , and the type species. The name St• probosc ideum has to be chosen because of a r t i c l e 11.3 of the ICBN (1978). Ralfs' description being inadequate, I further 200 suggest that i t be emended to include Schmidle's description of St. borgeanum. A remark i s in order about the sp e l l i n g of the species name. West et a l . (1923; p. 29) used the name St.  probosc idium instead of probosc ideum as a few other authors have done (Wolle 1882, Messikommer 1942, Thomasson 1952). Why this happened is uncertain, as W. West (1890) used the correct name St. proboscideum. Without any doubt, the name probosc ideum was used both by Ralfs (1848; p. 139) and Archer (in Pritchard 1861; p. 742). b) St. probosc ideum var. productum Messikommer 1942 (p. 165; p l . 17 f i g . 3) P l . F F i g . 1: "Die neue Varietat besitzt einerseits Ahnlichkeit mit St. probosc idium (Breb.) Arch., anderseits mit St.  Borgeanum Schmidle. Zum letzteren kann unsere Form nicht gezogen werden, weil ihre Zellarme gegen das Ende zu zu schlank sind und am Scheitel nur 3 g l e i c h z e i t i g sichtbare, aber gut entwickelte Stachelchen tragen. Gegenuber St. probosc idium bedeutet dieses Moment kennen Widerspruch. Da nach der Auffassung von Gronblad (1926) pag. 26 St.  borgeanum nicht mit St. probosc idium i d e n t i f i z i e r t werden kann, wie dies in West (1904-1923) pag. 129 (V) geschieht, so kommt fur unsere Anschlussbestrebungen einzig St. probosc idium in Frage. Unsere Form unterscheidet sich aber von diesem neben anderen kleineren Abweichungen hauptsachlich durch ihre langer ausgezogenen und gegen das Ende zu mehr allmahlich verschmalerten Zellarme. "Forma nostra a forma typica praecipue d i f f e r t processibus longioribus apicem versus graduatim attenuatis. - "Long. 32 1/2 -33 u, l a t . (cum process, sed sine acul.) 33-38 1/2 u, isthm. 12 1/2 This variety i s distinguished by the processes which are 201 g r a d u a l l y a t t e n u a t e d t o w a r d s t h e e x t r e m i t y a n d t i p p e d w i t h t h r e e s p i n e s . T h e n u m b e r o f s p i n e s a t t h e e n d o f t h e p r o c e s s e s i s a f e a t u r e w h i c h h a s b e e n s h o w n t o v a r y c o n s i d e r a b l y i n b o t h t h e p r e s e n t s t u d y a n d t h e l i t e r a t u r e . I t i s n o t a g o o d t a x o n o m i c a l c h a r a c t e r i s t i c . V a r i e t y p r o d u c t u m i s c i t e d a s a s y n o n y m o f t h e s p e c i e s S t .  b o r g e a n u m b y T h o m a s s o n ( 1 9 5 7 ) ; h o w e v e r , t h e c e l l s h e s t u d i e d a r e w i d e r t h a n M e s s i k o m m e r ' s , L = 3 6 - 4 5 ; Kcsp.) =. 5 2 . 5 - 6 0 y m . O t h e r w i s e t h e d e s c r i p t i o n s a r e i n a g r e e m e n t . 3 . S p e c i e s r e l a t e d t o S t . p r o b o s c i d e u m f . m i n o r T h e f o l l o w i n g s p e c i e s i s c l o s e l y r e l a t e d t o S t .  p r o b o s c i d e u m f o r m a m i n o r . S i n c e i t s name h a s b e e n w i d e l y u s e d a m o r e t h o r o u g h i n v e s t i g a t i o n i s s u g g e s t e d b e f o r e d r a w i n g a n y c o n e l u s i o n s . S t . p o l y m o r p h u m B r e b i s s o n e x R a l f s 1 8 4 8 ( p . 1 3 5 ; p i . 2 2 , f i g . 9 , p i . 34 f i g . 6 ) P i . F F i g . 8 : " . . . s e g m e n t s r o u g h w i t h m i n u t e g r a n u l e s , h a v i n g o n e a c h s i d e a s h o r t p r o c e s s t i p p e d w i t h s p i n e s ; e n d v i e w t h r e e - t o s i x - r a y e d . F r o n d m u c h s m a l l e r t h a n t h a t o f S t a u r a s t r u m g r a c i l e , d e e p l y c o n s t r i c t e d a t t h e m i d d l e ; s e g m e n t s i r r e g u l a r i n f o r m , b u t g e n e r a l l y b r o a d e r t h a n l o n g . E a c h s i d e t e r m i n a t e s i n a s h o r t t r u n c a t e p r o j e c t i o n o r p r o c e s s , w h i c h i s s c a r c e l y l o n g e r t h a n b r o a d