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The taxonomy and morphological variation of distromatic ulvaceous algae (Chlorophyta) from the northeast… Tanner, Christopher Eugene 1979

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THE TAXONOMY AND MORPHOLOGICAL VARIATION OF DISTROMATIC ULVACEOUS ALGAE (CHLOROPHYTA) FROM THE NORTHEAST PACIFIC by CHRISTOPHER EUGENE TANNER B.A. (Honours), Occidental College, 1972 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  in THE FACULTY OF GRADUATE STUDIES (Botany Department) We accept this thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA April, 1979  © Christopher Eugene Tanner, 1979  In presenting this thesis in partial  fulfilment of the requirements f o r  an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this t h e s i s for scholarly purposes may be granted by the Head of my Department or by his representatives. of  It is understood that copying or p u b l i c a t i o n  this thesis f o r financial gain shall not be allowed without my  written permission.  Depa rtment  The University of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  C a r l Linnaeus:  f a t h e r o f p l a n t s y s t e m a t i c s and o f Ulya.,  iii  Research Supervisor:  iv  Dr. Robert F. Scagel ABSTRACT  As a r e s u l t of herbarium, f i e l d and culture studies, s i x species of Ulya Linnaeus, U. c a l i f o m i c a W i l l e , U. f a s c i a t a D e l i l e , U.  fenestrata  Postels et Ruprecht, U. r i g i d a C. Agardh, U. stenophylla Setchell et Gardner and U. taeniata (Setchell)  Setchell et Gardner, are recognized for the north-  east P a c i f i c (west coast of North America).  The p o s i t i o n of a seventh  species, U. conglobata Kjellman, remains unclear.  Six taxa previously  recognized for the northeast P a c i f i c are reduced to synonyms of other known species.  Ulva angusta Setchell et Gardner and U. s c a g e l i i are reduced to  synonyms of U. c a l i f o m i c a . U. fasciata f.  Ulva expansa (Setchell)  Setchell et Gardner and  lobata Setchell are reduced to synonyms of U.  fenestrata.  Ulva costata (Howe) Hollenberg and U. d a c t y l i f e r a Setchell et Gardner are reduced to synonyms of U. taeniata.  Generic and s p e c i f i c taxonomic  criteria  for Ulva are examined and evaluated. A large degree of morphological and anatomical v a r i a t i o n was observed i n herbarium specimens and i n f i e l d populations of Ulva.  Some of t h i s v a r i a -  tion i s related to differences i n environmental parameters.  Dentation i n U.  taeniata i s reduced or eliminated with an increase of water  temperature,  while blade thickness increases with an increase of water temperature. result specimens from the southern part of i t s range are often identified.  As a  incorrectly  The s i z e , shape and thickness of t h a l l i i n populations of U.  fenestrata from the west coast of Vancouver Island and from Vancouver vary s i g n i f i c a n t l y with v e r t i c a l p o s i t i o n i n the i n t e r t i d a l zone and with wave exposure. thickness.  Most species of Ulva show some seasonal v a r i a t i o n i n size and Morphology i s generally more conservative than blade thickness  or c e l l dimensions.  Pyrenoid number i s useful for separating U. c a l i f o m i c a  from other species; however, i n species with more than one pyrenoid per c e l l , the number i s not consistent and cannot be used as a taxonomic c r i t e r i o n .  V  Studies of reproduction, development and interspecific hybridization potential confirmed observations made i n the f i e l d . does not produce marginal dentation above 16° C. in U. califomica varies with temperature.  In culture U. taeniata  Development and morphology  At relatively low temperatures  (7°-ll° C) upright filaments develop before the basal systems and result in plants similar to U. scagelii from British Columbia.  At higher temperatures  (13°-19° C) the basal system i s initiated f i r s t and develops into an extensive basal system that produces numerous upright germlings. The resulting tufted plants are similar to U. califomica from southern California.  These  two species also form viable zygotes when crossed, supporting the synonymy of U. scagelii with U. califomica.  As living specimens of U. fascia ta were  not encountered in the northeast Pacific, an isolate from Hawaii was used for the culture study of the reproduction and development of this species. This Hawaiian isolate demonstrated an unusual form of reproduction. Marginal vegetative cells round up and develop into aplanospores that divide into a floating multicellular globose stage. The cells of the globose stage eventua l l y release biflagellated swarmers that develop into normal appearing germlings . A cytological study was undertaken to determine i f species of Ulva from the northeast Pacific differed i n their chromosome numbers. A l l of the species of Ulva studied have a similar haploid chromosome number of around 8 or 9.  Following parthenogenetic development of gametes, haploid, diploid and  dikaryotic cells are occasionally observed i n the same germling.  The dikary-  otic cells may represent a transitional stage in the doubling of the chromosome number.  In a few of these parthenogenetic germlings some of the cells  become enlarged and multinucleate.  These cells may have lost the capacity  for cytokinesis. A diminutive distromatic ulvaceous alga was encountered i n southern  California.  T h i s a l g a resembles U l v a m o r p h o l o g i c a l l y ; however, i t s d e v e l o p -  m e n t a l p a t t e r n i s d i s t i n c t l y d i f f e r e n t from U l v a and o t h e r u l v a c e o u s  algae.  I n U l v a t h e d i s t r o m a t i c b l a d e d e v e l o p s by the c o l l a p s e o f a monostromatic tubular germling.  I n t h i s a l g a the d i s t r o m a t i c b l a d e forms by  d i v i s i o n s p a r a l l e l t o the s u r f a c e o f the g e r m l i n g .  longitudinal  A new genus and s p e c i e s ,  C h l o r o p e l t a c a e s p i t o s a , a r e proposed and d e s c r i b e d f o r t h i s a l g a .  vii TABLE OF CONTENTS ABSTRACT  iv  TABLE OF CONTENTS  vii  LIST OF TABLES  xi  LIST OF FIGURES  xii  ACKNOWLEDGEMENTS  xv  I.  GENERAL INTRODUCTION  1  II.  REVIEW OF THE CLASSIFICATION OF ULVACEOUS GREEN ALGAE  4  A.  GENERIC CONCEPTS  4  B.  FAMILY, ORDER AND CLASS CLASSIFICATION  9  C.  PACIFIC NORTH AMERICAN SPECIES OF ULVA  13  D.  EVALUATION OF TAXONOMIC CRITERIA  ..  1.  Thallus Morphology  2.  Thallus Thickness, Shape and Dimensions of C e l l s , and Pyrenoid Number  3.  4. III.  15 19  21  Reproductive Details and I n t e r s p e c i f i c Hybridization Potential  22  Germination and Developmental Patterns  23  MORPHOLOGICAL AND ANATOMICAL VARIATION  25  A.  25  B.  METHODS 1.  Collections and Herbarium Studies  25  2.  I n t e r t i d a l Transects  33  3.  Hydrographic Data  35  HYDROGRAPHY OF STUDY AREA  36  1.  Temperature and S a l i n i t y Measurements i n Barkley Sound  D.  RESULTS  37 40  Vlll  1. Ulva califomica, Ulva scagelii, Ulva angusta  40  2.  Ulva fenestrata, Ulva expansa, Ulva lobata  54  3.  Ulva rigida  75  4. Ulva stenophylla 5.  78  Ulva taeniata, Ulva costata, Ulva dactylifera, Ulva fasciata  85  6. Chloropelta caespitosa  103  D. DISCUSSION  107  1.  Geographic Variation i n Morphology and Anatomy  107  2.  Wave Exposure and Intertidal Position  109  3.  Seasonal Variation  110  4. Morphological and Anatomical Characteristics as Taxonomic Criteria IV.  .  Ill  GROWTH, DEVELOPMENT AND LIFE HISTORIES  113  A.  CULTURE METHODS  113  1.  Media and Apparatus  113  2.  Establishment and Examination of Cultures  115  B. LIFE HISTORIES, REPRODUCTIVE DETAILS AND DEVELOPMENTAL PATTERNS  120  1.  Ulva  120  a. Ulva califomica, Ulva scagelii  125  b. Ulva fasciata  131  c. Ulva fenestrata  134  d. Ulva stenophylla  142  e. Ulva taenia ta  146  Chloropelta caespitosa  150  2.  C. RESPONSES TO VARIATION IN TEMPERATURE AND SALINITY 1.  Ulva califomica, Ulva scagelii  157 157  ix 2. Ulva fenestrata  .  168  3. Ulva stenophylla  168  4. Ulva taeniata  168  5. Chloropelta caespitosa  175  D. HYBRIDIZATION EXPERJJMENTS  175  1. Ulva californica, Ulva scagelii  175  2. Ulva fenestrata  176  3. Ulva fenestrata with Ulva californica and  E.  Ulva scagelii  176  4. Ulva lactuca  176  DISCUSSION  179  1. Life Histories and Reproductive Details  179  2. Developmental Patterns  180  a.  Ulva  180  b.  Chloropelta  183  3. Hybridization Experiments V. CxTOLLXJICAL STUDIES  VT.  186 187  A. METHODS  187  B. RESULTS  189  C. DISCUSSION  192  GENERAL DISCUSSION  194  A.  SPECIES AFFINITIES  194  1. Ulva californica, Ulva scagelii, Ulva angusta  194  2. Ulva stenophylla, Ulva taeniata, Ulva costata, Ulva dactylifera, Ulva fasciata  197  a.  Ulva stenophylla  198  b.  Ulva taeniata  200  c.  Ulva fasciata  202  X  3. Ulva fenestrata, Ulva expansa, Ulva lobata, Ulva rigida, Ulva conglobata  203  a.  Ulva fenestrata  203  b.  Ulva rigida  204  c.  Ulva conglobata  205  4. Chloropelta caespitosa  206  B. KEY TO THE DISTROMATIC ULVACEOUS ALGAE FROM THE NORTHEAST PACIFIC C. TAXONOMIC CONCEPTS 1. Ulva califomica  207 209 ...... 211.  2. Ulva conglobata  214  3. Ulva fasciata  216  4. Ulva fenestrata  217  5. Ulva rigida  222  6. Ulva stenophylla  224  7. Ulva taenia ta  227  8. Chloropelta caespitosa  232  VII. SUMMARY LITERATURE CITED  234 236  XI  LIST OF TABLES 1. Development of the generic concept of Ulva  5  2. Various classification schemes for the ulvaceous algae  11  3.  16  Species of Ulva reported for the northeast Pacific  4. Herbaria from which specimens were borrowed and studied  26  5. Locations, dates and physical parameters of Ulva transects  34  6. Blade thickness, c e l l dimensions i n transverse section and.the number of pyrenoids per c e l l i n herbarium specimens of Ulva and Chloropelta  41  7. Comparison of thallus length (cm) i n transect samples showing the number of measurements (n), the means (x), standard deviations (SD), and the value of "student t"  64.  8.  9. 10. 11. 12.  Comparison of thallus thickness (urn) i n transect samples showing the number of measurements (n), the means (x), standard deviations (SD), and the value of "student t" ...  66  Seawater enrichment culture medium  114  Reproductive and developmental details observed i n isolates of Ulva and Chloropelta caespitosa  126  Isolates of Ulva califomica and Ulva scagelii studied i n culture  128  Isolates of Ulva fenestrata and related forms studied i n culture  135  13.  Isolates of Ulva stenophylla studied i n culture  143  14. 15.  Isolates of Ulva taenia ta studied i n culture Conditions under which isolates of Ulva and Chloropelta _ caespitosa were cultured to study the effects of temperatures and salinity on development and morphology  147  Chromosome numbers i n the Ulvaceae  188  16.  158  xii  LIST OF FIGURES 1.  C r i t e r i a used to separate the 12 species of Ulva previously reported f o r the northeast P a c i f i c  ......... . r  2.  Map of study area i n the northeast P a c i f i c  3.  Map of study area i n Barkley Sound, Vancouver Island  30  4. 5.  A e r i a l photographs of transect s i t e s i n Barkley Sound S a l i n i t y and temperature at the surface and a depth of 3 meters at two stations i n Barkley Sound between May, 1975 and May, 1976  32  6.  7. 8.  9. 10.  ...  18 28  39  Herbarium specimens of Ulva c a l i f o r n i c a and specimens morphologically intermediate between U. c a l i f o r n i c a and U. s c a g e l i i  44  Herbarium specimens of Ulva s c a g e l i i from B r i t i s h Columbia and Washington  46  Surface and sectional micrographs of Ulva c a l i f o r n i c a from southern C a l i f o r n i a , U. s c a g e l i i from B r i t i s h Columbia and U. angusta (Isotype material) T  49  a,b. Isotype material of Ulva angusta. c a l i f o r n i c a (U266.5) grown i n culture  51  c. Specimen of U.  a. Relationship between blade length and blade width i n herbarium specimens of Ulva c a l i f o r n i c a , U. s c a g e l i i and U. angusta. b. Relationship between blade length and Tatitude i n herbarium specimens of U. c a l i f o r n i c a and U. s c a g e l i i  53  11.  Type material of lobed and expanded species of Ulva  56  12.  Lobed and expanded specimens of Ulva from the northeast Pacific  58  Lobed and expanded specimens of Ulva from the northeast P a c i f i c , several of which show varying degrees of perforations  60  Surface and sectional micrographs of Ulva fenestrata and related species from the northeast P a c i f i c  62  Relationships of blade length and width with v e r t i c a l p o s i t i o n above chart datum i n Ulva fenestrata along three i n t e r t i d a l transects i n Barkley Sound and one i n Burrard Inlet  68  Relationship between blade thickness and v e r t i c a l p o s i t i o n above chart datum i n Ulva fenestrata along three i n t e r t i d a l transects i n Barkley Sound and one i n Burrard Inlet  70  13. 14. 15.  16.  xiii 17.  18. 19.  a. Relationship between blade thickness of.Ulva fenestrata along three intertidal transects perpendicular to the shoreline and time exposed to a i r calculated from the predicted tide level (Canadian Hydrographic Service, 1974). b. Percentage of specimens of U. fenestrata with one pyrenoid per c e l l and percentage with 2-4 pyrenoids per c e l l at d i f f e r ent vertical positions above chart datum along an intertidal transect (Kirby Point; ll-VII-75)  72  Changes in morphology of Ulva fenestrata along a vertical transect (Kirby Point; ll-VII-75)  74  Morphology and anatomy of Ulva rigida from the northeast Pacific  ;  77  20.  Herbarium specimens of Ulva stenophylla  80  21. 22.  Surface and sectional micrographs of Ulva stenophylla a. Relationship between blade length and blade width in herbarium specimens of Ulva stenophylla from Barkley Sound. b. Relationship between blade length and time of year in herbarium specimens of U. stenophylla from Barkley Sound .......  82  84  23.  Herbarium specimens of Ulva taeniata and U. fasciata from California  24.  Surface and sectional micrographs of Ulva taeniata and related species  25.  Morphology and anatomy of the type material of Ulva fasciata f. costata (NY)  91  a.. Relationship between length of marginal teeth and latitude in herbarium specimens of Ulva taeniata. b. Relationship between blade thickness and latitude in herbarium specimens of U. taeniata. c,d. Maximum and minimum yearly surface water temperatures along the west coast of North America  94  Photographs of Brady's Beach transect in the late summer (a; 15-IX-74) and in the winter (b; 22-11-75)  96  a. Seasonal variation in height of Brady's Beach relative to chart datum caused by the movement of sand, b. Relationship.between.blade length and vertical position above chart datum in Ulva taeniata along a transect perpendicular to the waterline (Brady's Beach; 16-VI-76)  98  26.  27. 28.  29. 30.  87 :  89  Winter and.summer specimens of Ulva taeniata from Barkley Sound  100  a. Relationship between blade length and blade width in herbarium specimens of Ulva taeniata. b. Relationship between blade length and time of year in. herbarium specimens of U. taeniata from Barkley Sound  102  xiv  31. 32.  Habit j morphology and anatomy of.field.specimens of Chloropelta caespitosa  106  a. Temperature gradient.table.. b. Flow.table.for culturing:. large specimens  117  33.  Different early developmental patterns in Ulva  123  34.  Reproduction and development of Ulva.californica.and .  .  U. scagelii  130  35.  Reproduction and development of Ulva fasciata from Hawaii  133  36.  Reproduction and development of Ulva.fenestrata and. related species  138  37.  Culture of Ulva fenestrata  140  38.  Reproduction and development of Ulva stenophylla  145  39.  Reproduction and development of Ulva taeniata  149  40.  Reproduction and development of Chloropelta caespitosa  152  41.  Development of ChloropelLa caespitosa  154  42.  Development of.Ulva scagelii (U335.5) at.different temperatures over a 3 week period Morphology of 4 week-old germlings of Ulva scagelii (U335.5) grown at different temperatures Morphology of 8 week-old germlings.of Ulva californica (U290) grown at different temperatures a. Growth in diameter of basal discs df Ulva scagelii (U335.5) at different temperatures, b. Growth i n length of blades °f scagelii (U335.5) at different temperatures.............  43. 44. 45.  161 163 165 167  46.  Growth of Ulva i n culture at different salinities  170  47.  Growth of Ulya stenophylla at different salinities at 10° C and Tl) C  172  Morphology of 7 week-old germlings of Ulva taeniata (U321) grown at different temperatures  174  49.  Results of crossing experiments  178  50.  a,b. Planes of division along nondentate and dentate margins in transverse section. c. Developmental patterns in various genera belonging to the Ulvaceae. Transverse sections. d. Development of Chloropelta i n longitudinal section  185  Chromosome studies of Ulva and Chloropelta  191  48.  51.  XV  ACKN0WLFJX3EMENTS  I would like to thank the numerous people and institutions who made this study possible.  To Dr. R. F. Scagel, Dr. Janet Stein, and other members  of the Botany faculty I owe a special thanks for the patience, advice and support that they have given me.  Financial support for this study was pro-  vided by a National Research Council of Canada Grant (A-4471) to Dr. Scagel and NRC Postgraduate Scholarships.  Among the people I am indebted to are  Julie Celestino for always giving a helping hand when asked; Miriam Haylock and other staff members of the Bamfield Marine Station; and Drs. Isabella Abbott, Jim Norris, Robert Setzer, Paul Silva, K. L. Vinogradova and others for making herbarium specimens available for study.  Thank you to Phil  Lebednik and Tom Mumford for providing pertinent literature and advice. To Gary Court, Jolie Mayer and David Walker, your friendship made graduate school enjoyable. A special thanks to my office, climbing and collecting partner, Michael Hawkes. I only hope that our climbing days together are not over. To my wife, Jean, I owe more than I can express for her unfailing support and patience. I hope that now I can make up for the numerous lonely evenings that you have spent at home by yourself.  1  I.  GENERAL INTRODUCTION The ulvaceous green algae are an assemblage o f genera u n i t e d p r i m a r i l y  by the presence of a monostromatic o r d i s t r o m a t i c , parenchymatous t h a l l u s i n at l e a s t part of t h e i r l i f e h i s t o r i e s .  Except f o r basal r h i z o i d a l c e l l s ,  which may be m u l t i n u c l e a t e , the c e l l s of the parenchymatous t h a l l u s are u n i nucleate and g e n e r a l l y have s i n g l e p a r i e t a l c h l o r o p l a s t s w i t h one or more pyrenoids.  Reproduction i s by q u a d r i f l a g e l l a t e d ( o c c a s i o n a l l y b i f l a g e l l a t e d )  zoospores and isogamous or anisogamous, b i f l a g e l l a t e d gametes.  The d e l i m i -  t a t i o n of genera and species i n t h i s group has always been an enigma t o phycologists because o f the l a c k o f good taxonomic c r i t e r i a and the large degree of morphological and anatomical p l a s t i c i t y encountered.  Classically,  species were separated on e a s i l y observable c h a r a c t e r i s t i c s such as t h a l l u s s i z e , shape, t h i c k n e s s , c e l l dimensions and pyrenoid numbers.  Many o f these  c r i t e r i a were found t o vary g r e a t l y ( S e t c h e l l and Gardner, 1903; van den Hoek, 1964), i n some instances i n response t o environmental f a c t o r s (Vinogradova, 1974; T i t l y a n o v , e t a l . , 1975; Steffensen, 1976a). Recently, researchers have recognized the value of using r e l a t i v e l y stable c r i t e r i a , such as reproductive d e t a i l s , germling ontogeny and h y b r i d i z a t i o n p o t e n t i a l , along w i t h morphological and anatomical c h a r a c t e r i s t i c s to d e l i m i t species.  Using these c r i t e r i a , B l i d i n g (1963, 1968) e f f e c t i v e l y  d e l i m i t e d the European members of the U l v a l e s . I n s i m i l a r but l e s s extensive studies several French researchers worked on the ulvaceous algae from France and Morocco (Cauro, 1958; Dangeard, 1958a, 1959), and Kapraun (1970) i n v e s t i g a t e d species of Enteromorpha and Ulva from Port Aransas, Texas. Numerous studies have been made on i n d i v i d u a l species. The northeast P a c i f i c , defined f o r t h i s study as the coast from the A l e u t i a n I s l a n d s , A l a s k a , t o the southern t i p of Baja C a l i f o r n i a , Mexico, i s second only t o New Zealand i n the number of species of Ulva reported i n the  2 literature.  A l l but one (Chihara, 1968) of the 12 species reported for the  northeast Pacific were described entirely on morphological and anatomical characteristics.  L i t t l e i s known about the l i f e histories and development  of these species, and, although a large amount of morphological variation has been noted (Setchell and Gardner, 1903), no studies on morphological or anatomical variation have been published for the northeast Pacific. This thesis i s the result of an extensive investigation of the species of Ulva from the northeast Pacific with the goal of re-evaluating the taxonomic criteria on which they were based. the course of the study.  Four approaches were taken during  First, morphological and anatomical characteristics  of living and herbarium specimens from the northeast Pacific as well as from other areas of the world were studied and compared. This included the study of a l l pertinent type material that could be located. Next, l i f e histories, reproductive details and germling development were studied i n culture for the various morphological types collected i n the f i e l d .  Germlings were grown  under different temperatures and salinities to determine i f these factors could influence developmental patterns and morphology. From the information gained from herbarium, field and culture studies, several species could be delimited with confidence.  In a few instances hybridization experiments  were used to check species. Third, several transects were established to determine the relationship between taxonomic characteristics and some environmental factors such as position i n the intertidal or subtidal zones and wave exposure.  Last, cytological studies were made for most of the species i n an  attempt to determine the value of chromosome number i n delimiting species. During the study, a diminutive, distromatic alga previously referred to as Ulva was.collected and studied. The morphology and i n i t i a l stages of development of'.this alga were similar to Ulva, but the later stages of development followed a pattern to my knowledge undescribed for the green  3 algae.  This alga is tentatively given the name of Chloropelta caespitosa.  To determine the affinities of Chloropelta with other algae, the literature on the ulvaceous algae was surveyed (Section II).  4 II. A.  REVIEW OF THE CLASSIFICATION OF ULVACEOUS GREEN. ALGAE GENERIC CONCEPTS Ulva i s an ancient name, having been used frequently by the Latin poets  to refer to marsh plants (Greville, 1830; Setchell and Gardner, 1920b). The name apparently originated from the Celtic u l , which means water (Greville, 1830).  In Ray's third edition of Synopsis Methodica (1724) Ulva was listed  as a leafy moss and included aquatic plants of any color that were thin, flat and "quandoque tubulosis" (at some time or other tubular). Twelve polynomial species were listed, seven of which were added by Dillenius, a contemporary of Linnaeus, who revised the third edition of the Synopsis (Steam, 1973). Linnaeus, who borrowed heavily from Ray and Dillenius, included as binomials five of their species i n his Species Plantarum (1753), a sixth that Ray had placed under Fucus and three that had been described i n previous publications (Table 1). Modern botanical nomenclature starts with Linnaeus, and, hence, his work is important for determining the generic.concept of Ulva. Ulva included a variety of unrelated algae.  Unfortunately,  Of the nine species listed i n the  Species Plantarum, eight have since been removed to other genera (Silva, 1952; Papenfuss, 1960; Table 1).  Linnaeus (1754), as did Ray, at f i r s t considered  the genus Ulva to be characterized by hollow plants and probably used Enteromorpha intestinalis (Linnaeus) Link as the basis of his description (Papenfuss, 1960). However, later i n his Systerna Vegetabilium he changed his description of Ulva as a hollow membrane to simply a membrane (Lamouroux, 1813). Lamouroux (1813) removed most of the non-chlorophycean algae with the exception of some modern Porphyra species and split Ulva species into two sections depending on whether they were planular (Ulva F o l i i s planis) or tubular (Ulva F o l i i s fistulosis).  Three of the nine taxa listed i n the  Table 1. Development of the generic concept of Ulva.  Linnaeus (1753)  Ray (1724)  Modern Interpretation  References i  1  Ulvae marinae  Ulva lactuca  Ulva lactuca L.?  U. umbilicalis  Porphyra umbilicalis  C. agardh (1824) as P. . laciniata f. umbilTcalis  U. linza  U. linza L. or Enteromorpha linza  J. Agardh (1883)  U. intestinalis  Enteromorpha intestinalis  Link (1820)  U. compressa  E. compressa  Greville (1830)  U. confervoides  Ceramium rubrum  C. Agardh (1828); Silva (1952)  U. granulata  Botrydium granulatum  Greville (1830); Silva (1952)  U. latissima  Laminaria saccharina  Setchell and Gardner (1920b); Silva (1952); Papenfuss (1960)  Nostoc pruniforme  C. Agardh (1824); Silva (1952)  U. pruniformis  \  1  Papenfuss (1960); Bliding (1968).  Papenfuss (1960) and Bliding (1968) disagree as to whether the type specimen of Ulva lactuca L. f i t s the modern interpretation of that species.  6 section U. F o l i i s planis are presently considered valid species of Ulva. Later C. Agardh (1824) established the genus Porphyra, removing the last of the red algae from Ulva. In the 1800's Ulva was split into several genera on morphological and anatomical characteristics.  A number of different generic names were proposed  for hollow species, but Enteromorpha Link (1820) was the f i r s t to become firmly established (Greville, 1830; Silva, 1952).  In 1823 Bory described the genus  Percursaria for unbranched filaments composed of two longitudinal rows of cells (Kornmann, 1956).  Areschoug in 1851 separated the genus Letterstedtia  on the presence of lateral, more or less pinnate leaflets (Papenfuss, 1960). Letterstedtia as i n the modern concept of Ulva i s distromatic.  Monostromatic  species were placed i n Ulvaria by Ruprecht (1851) and i n Monostroma by Thuret (1854).  Though Monostroma i s antedated by Ulvaria the wide use of Monostroma  for monostromatic ulvaceous algae led Papenfuss (1960) to propose that i t be conserved against Ulvaria.  Capsosiphon was established by Gobi in 1879 for a  tubular plant that differed from Enteromorpha by lacking rhizoidal cells (Bliding, 1968) and by having cells i n groups of two's and four's embedded i n a mucilaginous matrix material (Papenfuss, 1960). More recently cytological and reproductive details were used to establish genera.  Chadefaud (1957) described Feldmannodora on the shape of the chloro-  plast, and Chapman (1952) described Gemina and Lobata separating from Enteromorpha and Ulva on the presence of reproductive cells along the central axis. As many of the ulvaceous algae were cultured, reproductive, developmental and l i f e history differences became apparent and were used to establish new genera.  Blidingia was separated from Enteromorpha by Kyiin (1947) on the type  of i n i t i a l development and on the relatively small dimensions of vegetative cells.  Enteromorpha develops directly into an upright filament attached by  rhizoidal protuberances from the basal cells.  Blidingia germinates by a ger-  mination tube and develops an extensive prostrate disk before the formation of  7 the upright germling (Dangeard, 1961).  Dangeard (1952) separated Rhizenteron  from Enteromorpha also on developmental criteria.. Rhizenteron forms a thick tubercular growth at the base composed of coalesced rhizoids.  Eventually,  tubular fronds that resemble Enteromorpha grow out of the upper surface of the  tubercular base. A variety of reproductive details, l i f e histories and  developmental patters were found i n the monostromatic species (Suneson, 1947; Gayral, 1962, 1965; Kornmann, 1962, 1964; Kornmann and Sahling, 1962; Hirose and Yoshida, 1964; Kida, 1966; Dube, 1967; Bliding, 1968; Tatewaki, 1972). This variation caused some confusion and disagreement about characteristics to be used to separate genera and regarding nomenclature.  The species originally  placed in Ulvaria by Ruprecht (1851), U. fusca (Postels et Ruprecht) Ruprecht and U. splendens Ruprecht, were found to have l i f e histories consisting of an alternation of isomorphic sporophytic and gametophytic phases (Dube, 1967). Reproductive details and developmental patterns of Ulvaria closely resemble those of Ulva and Enteromorpha.  On the other hand, Thuret (1854) based  Monostroma on two species, one with a heteromorphic l i f e history, M. bullosum (Roth) Thuret, and the other, M. oxycoccum (Kutzing) Thuret  = M. oxyspermum  (Kiitzing) Doty , that lacked an alternation of generations.  Neither was desig-  nated the type (Bliding, 1968).  Monostroma bullosum and M. oxyspermum also  differ from each other and the species placed i n Ulvaria in their developmental patterns and the manner i n which swarmers are released (Tatewaki, 1972).  Gay-  ral (1965) proposed that Monostroma be typified by M. oxyspermum, that Ulvaria be revived for the isomorphic species and that the heteromorphic species be placed i n a new genus, Ulvopsis Gayral.  Kornmann (1964), Bliding (1968) and  Vinogradova (1974) proposed M. bullosum as the lectotype of Monostroma, and Bliding (1968) placed M. oxyspermum i n Ulvaria as U. oxysperma (Kiitzing) B l i d ing, noting the similarity i n developmental patterns.  He also described the  genus Kornmannia for a monostromatic species, M. leptodermum Kjellman, that  8 resembled Blidingia in. cell size and development,  Kornmannia lacks pyrenoids  and differs i n l i f e history from M. bullosum (Eliding, 1968; Tatewaki, 1972). Vinogradova (1969, 1974) accepted most of Bliding's generic concepts but differentiated M. oxyspermum from Monostroma and Ulvaria by placing i t i n the new genus, Gayralia Vinogradova based on the method by which swarmers were released.  In Ulvaria, as well as i n Ulva and Enteromorpha, swarmers are released  one at a time through a small pore in the outer wall of the parental c e l l .  In  Monostroma species swarmers are released a l l at once through an irregular hole (Tatewaki, 1972).  In Gayralia swarmers are released by disintegration of the  parental c e l l wall.  Ulvaria and Gayralia also differ i n the manner i n which  the vesicular stage opens (Tatewaki, 1972).  Vinogradova (1969) also created  the new genus Protomonostroma Vinogradova for M. undulatum Wittrock.  This  species has a heteromorphic l i f e history but differs from other genera i n the type of development and method of swarmer release (Tatewaki, 1972). There i s s t i l l considerable disagreement regarding the criteria used to delimit genera of ulvaceous algae, particularly as noted previously for the monostromatic species.  Several workers have kept a l l the monostromatic species  in Monostroma (Scagel, 1966; Abbott and Hollenberg, 1976).  The differences be-  tween Ulva and Enteromorpha have been questioned (LeJolis, see Anderson, 1891; Silva, 1972; Bonneau, 1977).  These two genera have similar l i f e histories and  developmental patterns, and their separation i s complicated by the presence of intermediate morphological forms such as E. linza (Linnaeus) J. Agardh.  Some  feel that Letterstedtia i s not distinct enough from Ulva to warrant generic status (Papenfuss, 1960), whereas others accept this genus (Pocock, 1959; Chapman, 1964).  Papenfuss (1960) also questioned the validity of Gemina and  Lobata, suggesting that the special reproductive cells produced along the axis were actually rhizoidal cells f i l l e d with starch granules.  Chapman (1964)  maintained that these cells were reproductive structures.  The separation of  9  Blidingia from Enteromorpha has also been questioned.  Some isolates of  Blidingia show a l i f e history similar to that of Enteromorpha  (Prange, 1976),  and some species of Enteromorpha and Ulva produce extensive basal systems under some culture conditions (Gauro, 1958;  Baudrimont, 1 9 6 1 ) .  Even the typification of Ulva Linnaeus (1753) has been questioned. Though Linnaeus apparently had a hollow plant in mind when describing Ulva, this genus was subsequently narrowed to contain only the distromatic, bladed green algae. Only one of the original species, U. lactuca Linnaeus actually f i t s the modern concept of Ulva (Table 1 ) . Papenfuss (1960) examined the type of U_. lactuca and found that i t differed from the modern concept of this species.  He proposed that, because of the uncertainty of Linnaeus' concept  of Ulva, the genus be conserved i n the sense of Thuret ( 1 8 5 4 ) , and that i t be typified by U. rigida (C. Agardh) Thuret.  Bliding (1968) stated that the  type of U. lactuca f i t s the modern concept and that i t be retained as the type of Ulva. Despite the disagreement over generic concepts, certain patterns i n morphology, l i f e history and development are becoming clearer for this group. Supportive evidence such as Hori's (1972) study of pyrenoid structure i s helping to clarify relationships between genera.  However, because of the  ubiquitous distribution and large degree of morphological plasticity in this group, i t i s likely that more genera w i l l be proposed i n the future pn the basis of development and l i f e histories. B.  FAMILY, ORDER AND CLASS CLASSIFICATION Lamouroux i n 1813 established the family Ulvacees for uniform herbaceous  plants of green color.  In this he placed the genera Ulva, Asperococcus,  Bryopsis and Caulerpa. Dumortier i n 1822 latinized the spelling to Ulvaceae (Rhyne, 1973).  Whereas Greville (1830) and Harvey (1858) included i n the  10  Ulvaceae a variety of unrelated genera, Thuret (1854) defined i t as containing the ulvaceous genera Ulva, Enteromorpha and Monostroma. In 1934 Kunieda proposed that Monostroma be placed i n the separate family Monostromaceae (Suneson, 1947; Papenfuss, 1960; according to Bliding (1968) and Vinogradova (1974) the spelling is Monostromataceae Kunieda ex Suneson) on the basis of l i f e history.  Chapman (1952) proposed the new family Capso-  siphonaceae for Capsosiphon because of the lack of motile reproductive cells. However, Bliding (1968) and Chihara (1967) found that Capsosiphon produced flagellated swarmers, though in both instances the isolates did not show an alternation of generations.  These swarmers were released through an aperture  in the parental c e l l wall as a mass enclosed in an envelope (Chihara, 1967). This type of swarmer release is also found in Monostroma (Tatewaki, 1972). Papenfuss (1960) and Chihara (1967) suggested that there were insufficient differences between Capsosiphon and other genera in the Ulvaceae to justify separating i t into a new family.  Iwamoto (Bliding, 1968) considered Capso-  siphon to be more closely related to Monostroma than to Enteromorpha, whereas Gayral (1964), Bliding (1968) and Vinogradova (1974) thought that there were sufficient differences to justify a separate family.  Gayral (1971) suggested  that Capsosiphon was related to Monostroma oxyspermum (= Gayralia oxysperma) and that after further studies they may be placed in the same family. In 1968 Bliding proposed that Percursaria be transferred from the Ulvaceae to the new family Percursariaceae.  He suggested that Percursaria was  sufficiently different from other ulvaceous algae to justify transfer of i t because of: 1, the lack of a hollow stage during development of the upright thallus; 2, the lack of rhizoidal cells; 3, germination of reproductive cells into prostrate disks.  He has not been followed by more recent authors (Gay-  r a l , 1971; Vinogradova, 1974; Abbott and Hollenberg, 1976; Table 2 ) . Vinogradova in 1969 established the family Gayraliaceae to contain  Table 2. Various classification schemes for the ulvaceous algae. Papenfuss (1960)  Gayral (1964)  Bliding (1968)  Vinogradova (1974)  Kornmann and Sahling (1977)  Chlorophyceae Ulotrichales  Chlorophyceae Ulotrichales  Chlorophyceae Ulvales  Chlorophyceae Ulvales  Chlorophyceae Ulvales  Ulvaceae Capsosiphon Percursaria Enteromorpha Ulva Rhizenteron . FeIdmannodora  Capsosiphonaceae Capsosiphon  Capsosiphonaceae Capsosiphon  Capsos iphonaceae Capsosiphon  Capsosiphonaceae Capsosiphon  Ulvaceae Percursaria  Percursariaceae Percursaria  Ulvaceae Percursaria  Percursariaceae Percursaria  Enteromorpha Ulva Ulvaria  Blidingia  Blidingia  Ulvaceae Enteromorpha Ulva Ulvaria Monostromataceae Blidingia  Enteromorpha Ulva  Ulvaceae Enteromorpha Ulva  Ulvaria Monos tromataceae Blidingia  Blidingia  Monos tromaceae Kornmannia  Kornmannia  Kornmannia Codiolophyceae Monostroma ta1es Monostromataceae  Monostroma (including Ulvaria)  Ulvopsis Monos tromataceae Monostroma  Monostroma  Monostroma Gomontia Gayraliaceae Gayralia Protomonos troma  Monostroma  12  the genera, Gayral i a and Pro tomonos troma (Gayral, 1971; Vinogradova  1974).  These two genera are held together by a similar method of swarmer release, though they differ in developmental patterns (Tatewaki, 1972). Borzi i n 1895 transferred the Ulvaceae to the new order Ulotrichales (Rhyne, 1973).  Blackman and Tansley (1902) removed the Ulvaceae from the  Ulotrichales and placed them in the new order Ulvales on the basis of their parenchymatous construction in contrast with the filamentous construction of most ulotrichalean algae.  Further support for this separation came when  l i f e history studies demonstrated an alternation of isomorphic generations for Ulva and Enteromorpha (Hartmann, 1929; Foyn, 1929, 1934) and an alternation of heteromorphic generations for Ulothrix (Grosse, 1931).  However,  since then Monostroma has been shown to have a heteromorphic l i f e history, alternating with a "zygocyst" stage as does Ulothrix (Tatewaki, 1972).  Also,  some ulvaceous algae pass through a filamentous stage during their development, e.g., Ulva, Enteromorpha, Percursaria, Capsosiphon and Ulvaria (Bliding, 1968).  Further evidence against the separation of the Ulvales from the Ulo-  trichales was provided by Singh (1945, 1947) when he found that Fritschiella and Draparnaldiopsis had isomorphic l i f e histories.  These and other branched  filamentous green algae are either included i n the Ulotrichales (Setchell and Gardner, 1920b; Scagel, 1966; Abbott and Hollenberg, 1976) or placed i n a separate order, the Chaetophorales (Fritsch, 1935; Kylin, 1949; Round, 1963,  1971; Bold and Wynne, 1978).  Fritsch (1935, 1944) and Papenfuss (1960)  concluded that there was l i t t l e justification for separating the Ulvales from the Ulotrichales.  They have-been followed by some authors (Chapman, 1964;  Scagel, 1966; Abbott and Hollenberg, 1976), whereas others have retained the order Ulvales (Doty, 1947; Kylin, 1949; Smith, 1944; Bliding, 1968; Gayral, 1971;  Vinogradova, 1974; Bold and Wynne, 1978). Kornmann (1965) considered l i f e histories to be of primary  importance  13 and placed the heteromorphic species of Monostroma i n the Ulotrichales, at the same time maintaining the Ulvales for isomorphic ulvaceous algae. This treatment was followed by Round (1971).  Later tornmann (1973) elevated the  Monostromataceae to order level, Monostromatales, and placed i t i n the new class Codiolophyceae along with the Ulotrichales, Codiolales and Acrosiphonales.  These groups, though diverse i n morphology and development of the  macrophytic gametophyte, a l l had a unicellular "Codiolum" sporophyte.  Pre-  vious to this^ithe ulvaceous algae had always been placed i n the Chlorophyceae. Recently considerable attention has been given to c e l l structure and i n particular the mitotic and cytokinetic apparatus of green algal cells (Pickett-Heaps and Marchant, 1972; Stewart, Mattox and Floyd, 1973; PickettHeaps, 1975; Stewart and Mattox, 1975a, 1975b; Mattox and Stewart, 1977). Stewart and Mattox (1975a) suggested that most of the classical classifications of the green algae were superficial and that a natural system must i n corporate data on mitosis, cytokinesis, the ultrastructure of reproductive cells and biochemical characteristics.  According to the work of Stewart and  Mattox (1975b, 1978) the Ulvaceae (Ulva, Enteromorpha, Percursaria, PseudendocIonium and Trichosarcina) are distinctly different from ulotrichalean algae and possibly represent a phylogenetic line separate from the Chlorophyceae.  They have proposed that the ulvaceous algae be placed in a new  class, the Ulvaphyceae.  However, they have not studied any of the members  of the Monostromataceae, and the position of the heteromorphic ulvaceous algae remains unclear i n their scheme. Comparative ultrastructure studies of these algae w i l l hopefully help clarify the relationship of the Monostromataceae to the Ulvaceae. C.  NORTHEAST PACIFIC SPECIES OF ULVA Prior to the 20th century phycologists assigned northeast Pacific spe-  14 cimens of Ulva to already e s t a b l i s h e d A t l a n t i c species. l i s t e d i n h i s Nereis BoreaLi-Americana  Harvey (1858)  two species from the west coast: U.  f a s c i a t a D e l i l e and U. l a t i s s i m a Linnaeus.  From Harvey's d e s c r i p t i o n of U.  f a s c i a t a as undulate and i r r e g u l a r l y toothed, i t seems c e r t a i n that the specimens he examined were U. t a e n i a t a ( S e t c h e l l ) S e t c h e l l et Gardner.  Ulva  l a t i s s i m a was used as a c a t c h - a l l species f o r t h a l l i of various shapes.  In  1862 Harvey added two more species, U. r i g i d a C. Agardh and U. l i n z a L i n naeus, from herbarium specimens c o l l e c t e d by Dr. D. L y a l l on Vancouver I s l a n d and neighboring areas.  Anderson (1891) recorded from C a l i f o r n i a U.  f a s c i a t a , U. l a c t u c a , U. l a t i s s i m a and several species p r e s e n t l y placed i n Enteromorpha. The Phycotheca Boreali-Americana, issued and d i s t r i b u t e d by C o l l i n s , Holden and S e t c h e l l (1895-1919), included specimens of U. l a c t u c a var. l a t i s sima and var. r i g i d a as w e l l as several new taxa from the west coast.  Ulva  c a l i f o m i c a W i l l e (1899) was described from minute, cuneate t h a l l i c o l l e c t e d at P a c i f i c Beach, C a l i f o r n i a .  S e t c h e l l described four forms of U. f a s c i a t a :  f. expansa (1905), f. lobata (1901), f. t a e n i a t a (1901) and f. caespitosa (1901) ( C o l l i n s et a l . , 1895-1919).  C o l l i n s (1903) included a l l of these  taxa i n h i s paper on the Ulvaceae of North America. S e t c h e l l and Gardner are responsible f o r the concepts of most of the species p r e s e n t l y recognized f o r the northeast P a c i f i c .  I n 1903 S e t c h e l l  and Gardner reported only one species w i t h two v a r i e t i e s (U. l a c t u c a var. l a t i s s i m a and var. r i g i d a ) .  They summarized t h e i r conclusions at that time  (1903, p. 210): "A very considerable study of the species of Ulva along the e n t i r e western coast of North America i n d i c a t e s t h a t , while there may many forms, there i s probably only one species and very few v a r i e t i e s .  be The  h a b i t , s i z e , c o l o r and even the character of c e l l depends so much on the age and the environment of the specimen, that i t i s p o s s i b l e to trace a s e r i e s  15 from the quiet water inside a point of land to the exposed localities outside of i t which may include a l l the forms and intermediate conditions between the most distinct species as yet proposed under the genus," However, after further study Setchell and Gardner (1920a, 1920b) concluded that a number of species could be distinguished, and they listed thirteen for the northeast Pacific of which four were new,  three were new  combinations and one had not been reported from this area (Table 3). work remains the last extensive study of Ulva on this coast, and  Their  subsequently  phycologists have retained the same species with a few minor changes.  Ulva  vexata Setchell et Gardner was transferred f i r s t to Enteromorpha (Doty, 1947), and later to Blidingia as a variety of B. mimina (Norris, 1971). Ulva linza has been placed in Enteromorpha by most authors.  Scagel (1966)  suggested that U. latissima be reduced to a synonym of U. lactuca based on Papenfuss' report (1960) that the type of U. latissima was actually a Laminar ia . In 1968 Chihara described U. scagelii primarily on germination and developmental' patterns.  Hollenberg (1971) elevated Howe's U. fasciata f.  costata Howe (1914) to species level, U. costata (Howe) Hollenberg, and reported i t from southern California. Other authors that have discussed the species of Ulva in the northeast Pacific are Smith (1944), Doty (1947), Scagel (1966), Norris (1970) and Abbott and Hollenberg (1976). D.  EVALUATION OF TAXONOMIC CRITERIA The criteria used in the past to separate species of Ulva in the north-  east Pacific (Setchell and Gardner, 1920b; Smith, 1944; Doty, 1947; Scagel, 1966; Abbott and Hollenberg, 1976) are outlined i n Figure 1.  The emphasis was  placed on thallus size, shape, thickness, and c e l l height to width ratio in  Table 3.  Species of Ulva reported f o r the northeast P a c i f i c .  P a c i f i c Coast of North America  B r i t i s h Columbia  u . angusta Setchell et Gardner ' 1  u. californica W i l l e ' ' 1  2  2  3  u . costata (Howe) Hollenberg  2  u . d a c t y l i f e r a Setchell et Gardner ' 1  2  u . expansa (Setchell) Setchell et G a r d n e r ' ' ' 1  u . fenestrata Postels et R u p r e c h t ' ' 1  u . lactuca L i n n a e u s ' ' 1  2  3  2  u. scagelii Chihara ' 6  2  U. expansa ' ' 5  6  U. l a c t u c a ' '  5  1  2  3  6  2  U. l o b a t a ' ' 6  8  U. r i g i d a ' '  5  1  2  2  3  u . taeniata (Setchell) Setchell et  U. t a e n i a t a ' 7  Gardner ' ' ' ' 1  2  3  1 0  U. stenophylla  8  7  9  9  S e t c h e l l & Gardner (1920b)  6  S c a g e l (1973)  2  Abbott & Hollenberg (1976)  7  N o r r i s & Abbott (1972)  3  Doty (1947)  8  Lee (1965)  5  Scagel (1966)  Widdowson (1965)  9  10  C h i h a r a (1968)  5  5  6  1  5  9  U. s c a g e l i i '  1 0  u . stenophylla Setchell et G a r d n e r ' ' '  ^Hollenberg (1971)  7  1  1  1  5  U. f e n e s t r a t a ' '  5  u . lobata (Kiitzing) Setchell et G a r d n e r ' ' ' u . r i g i d a C. A g a r d h ' '  3  8  6  17  Figure 1.  Criteria used to separate the 12 species of Ulva previously reported for the northeast P a c i f i c Cell H/W ratio refers to c e l l height to width ratio in transverse section. In thin specimens H/W ratios approach 1. In thick specimens H/W ratios >^ 1.5. During normal development ("Ulva lactuca-type") reproductive.cells germinate directly and the upright germling begins to develop before the basal system. During abnormal development ("Ulva scaglii-type") reproductive cells germinate by means of a germination tube and.an extensive basal system develops before initiation of the upright germling (Chihara, 1968).  _ _ _ _ _ Ulva l e s s than 2 cm tall  ________ Ulva normal development  califomica  lactuca  cuneate, o r b i c u l a r , expanded or lobed  thin: 30-45 urn low c e l l H/W r a t i o  Ulva  scagelii  abnormal development more than 2 cm tall  Ulva  angueta  l i n e a r or narrowly oblanceolate Ulva  stenophylla  simple  l i n e a r or l a n c e o l a t e  Ulva  branched Ulva Ulva branched, dentate  8 50-100 um (or more) high c e l l H/W r a t i o  costata  midrib  taeniata  dactylifera  no midrib  thick:  -_——-—— lobed  Ulva  lobata  Ulva  rigida  Ulva  fenestrata  perforate  o r b i c u l a r , lobed or expanded expanded  Ulva expansa not perforate  19  transverse section. Much of the o r i g i n a l work on Ulva was based on herbarium specimens (Wille, 1899;  Setchell and Gardner i n Smith, 1947, p. 81; Hollen-  berg, 1971), and i n a few instances species were apparently described from single c o l l e c t i o n s (U. c a l i f o m i c a i n W i l l e , 1899; U. angusta i n Setchell and Gardner, 1920b).  Because of t h i s , l i t t l e was known about i n t r a s p e c i f i c  v a r i a t i o n due to age, environmental  conditions and genetic p l a s t i c i t y .  Setchell and Gardner (1920b) and Scagel (1966) recognized the need for culture studies to determine the v a l i d i t y of morphological and c r i t e r i a used to separate these species.  anatomical  The recent tendency i s to use  morphological and anatomical c r i t e r i a along with studies of morphogenesis and i n t e r s p e c i f i c h y b r i d i z a t i o n potential to separate species (van den Hoek, 1964; B l i d i n g , 1968; Kapraun, 1970; Rhyne, 1973).  The v a l i d i t y of the  various taxonomic c r i t e r i a i s discussed below:  1-  Thallus Morphology  Considerable morphological v a r i a t i o n has long been recognized for species of Ulva (Setchell and Gardner, 1903; van den Hoek, 1964; Chapman, 1964; B l i d i n g , 1968; Kapraun, 1970; algae (Klugh, 1922;  Steffensen, 1976a) and other  ulvaceous  B l i d i n g , 1938; Arasaki and Shihira, 1959; Burrows, 1959).  The parenchymatous, distromatic blade of Ulva offers few c h a r a c t e r i s t i c s that can be used to separate species.  Growth of the blade i s by d i f f u s e c e l l  d i v i s i o n s , and the r e s u l t i n g shape i s affected by numerous factors such as age, reproductive state, wave exposure, t i d a l factors, temperature, s a l i n i t y , l i g h t and b i o l o g i c a l factors such as grazing. strated that a single species from a New stages of growth f i t the diagnoses  Steffensen (1976a) demon-  Zealand estuary could at various  for f i v e d i f f e r e n t species.  Morphology  varied with age of the t h a l l u s , time of year, s a l i n i t y and whether the thallus was attached or f r e e - f l o a t i n g .  Titlyanov et a l . (1975) recorded  20 significant differences i n the size of t h a l l i of U. fenestrata Postels et Ruprecht from habitats of different wave exposure and at different times of the year.  The largest t h a l l i occurred in shallow, protected areas i n winter  and spring. Ulva species growing in the upper intertidal have been observed to be small and stunted (Lawson, 1956). Photosynthesis and growth are affected by exposure to a i r (Johnson et a l . , 1974), eutrophication (Waite and Mitchell, 1972; Steffensen, 1976b), and changes in temperature and salinity (Ogata and Matsui, 1965; Kjeldsen and Phinney, 1972; Yokohama, 1972; Zavodnik, 1975; Steffensen, 1976a). These factors affect the size and probably the morphology of t h a l l i .  Numer-  ous culture studies have been made of Ulva and other ulvaceous algae.  In some  studies cultured plants retained the morphological characteristics of the species (Foyn, 1955; Yoshida, 1965; Chihara, 1968, 1969).  In other studies  the morphology depended on the culture conditions (Provasoli, 1958,  1961;  Kapraun, 1970, Rhyne, 1973; Bonneau, 1977). Foyn (1960, 1961) obtained morphological variants in culture caused by genetic mutations. The preceding studies suggest that morphology must be used with caution and preferably with other characteristics.  However, in areas where there  are few species, morphology can occasionally be used effectively.  Kapraun  (1970) plotted thallus length against width for U. fasciata and U. lactuca from Port Aransas, Texas.  For these two species there was l i t t l e overlap.  In the northeast Pacific the large number of species reported and their similarities in morphology make this type of analysis d i f f i c u l t .  Some  species have distinctive taxonomic characteristics such as perforations (U. fenestrata) and dentation (U. rigida, U. taeniata), but even these vary with environmental factors.  According to Vinogradova (1974) the perforations in  U. fenestrata were caused by molluscs such as Littorina.  In "U. lactuca"  from New Zealand microscopic teeth were common in small attached plants but  21 absent in expanded plants (Steffensen, 1976a).  Also, i n Enteromorpha the  tendency to branch i s influenced by culture conditions (Burrows, 1959; Kapraun, 1970).  A similar tendency might be expected for dentations, which  are essentially short lateral branches of determinate growth. 2.  Thallus Thickness and Shape, Dimensions of Cells and Pyrenoid number  The lack of good gross morphological characteristics led to the use of blade thickness; size, shape and arrangement of cells; and the number of pyrenoids i n each c e l l for characterizing species (Bliding, 1968). However, as discussed by van den Hoek (1964) and Kapraun (1970), these characteristics often show considerable variation and overlap for different species.  Stef-  fensen (1976a) noted that changes i n cellular morphology were associated with changes in thallus morphology for a given species.  In U. fenestrata  from the northwest Pacific, cells i n surface view were either rounded or angular and varied significantly in dimensions for different localities and times of the year (Vinogradova, 1974).  Cell dimensions i n U. fenestrata  were apparently also influenced by temperature as the dimensions increased from north to south, and during the summer months when water temperatures were up to 15°(C) warmer than during the winter months. Vinogradova also noted a decrease in thickness with an increase of wave exposure.  Titlyanov  et a l . , (1975) did not find a significant change i n c e l l dimensions i n U. fenestrata from localities of different wave exposures, and c e l l dimensions i n surface view increased during the winter and early spring rather than in the summer. They suggested that low temperatures retarded division of cells and stimulated growth i n dimensions as i s reported i n phytoplankton (Jorgensen, 1968). The number of pyrenoids per c e l l has been used as a taxonomic criterion  22 (Bliding, 1968; Chihara, 1968, 1969).  This criterion can be useful for  species with one pyrenoid per c e l l , but for species with more than one, the pyrenoid number may vary considerably (van den Hoek, 1964). Pyrenoid numbers have in the past caused some confusion when errors were made in reporting numbers from herbarium material (Smith, 1947). 3.  Reproductive Details and Interspecific Hybridization Potential  Bliding (1963), van den Hoek (1964) and Kapraun (1970) reported that reproductive details and the results of hybridization experiments were of great value for separating species. Most species have a l i f e history consisting of an alternation of isomorphic sporophytic and gametophytic phases (Foyn,  1929,  1934, 1958, 1959; Bliding, 1968). The sporophyte typically produces quadriflagellated zoospores, and the heterothallic gametophytes produce biflagellated gametes.  In a few species only one type of swarmer has been observed  (Dangeard, 1957; Bliding, 1968), suggesting the loss of one of the two phases.  Dimensions of swarmers (Chihara, 1969) and whether gametes are iso-  gamous or anisogamous have also been used as taxonomic c r i t e r i a .  Smith (1947)  studied the reproduction of five species from California and found that only one, U. taeniata, had isogamous gametes. A l l of the species in Europe for which sexual reproduction has been reported have anisogamous gametes (Bliding,  1968) except for isolated populations (Meowus, 1938; Foyn, 1955). The results of hybridization experiments have proven useful for separat-  ing species.  Foyn (1955), Bliding (1963, 1968) and Kapraun (1970) suggested  the presence of interspecific f e r t i l i t y barriers.  In their studies fusion  occurred between gametes of different species, but the mating reaction was weak, and germlings never developed beyond a few cells.  However, Dangeard  (1963) successfully crossed isolates which he identified as U. lactuca and U. rigida.  Ardre (1967) described a species of Ulva in which cells of one  23  layer resembled those of J J . lactuca and c e l l s of the other layer resembled those of J J . r i g i d a .  She suggested the dimorphism was  caused by a h y b r i d i z a -  t i o n or "pseudo-hybridization" between U. lactuca and U. r i g i d a r e s u l t i n g i n a hybrid with g e n e t i c a l l y d i f f e r e n t layers, also been observed i n J J . conglobata  A similar.dimorphism  has  f. densa i n Japan (Okamura, 1918),  i s also the p o s s i b i l i t y of i n t r a s p e c i f i c f e r t i l i t y b a r r i e r s .  There  Such b a r r i e r s  have been demonstrated for other green algae (van den Hoek, 1964).  4.  Germination and Developmental Patterns  Germination and early developmental patterns are often d i f f e r e n t for d i f f e r e n t species.  In some instances these differences have been used as  the basis for describing new  species (Cauro, 1958;  Chihara, 1968).  t i o n i s d i r e c t i n most species, but i n a few a germination  Germina-  tube develops  p r i o r to c e l l d i v i s i o n as described for J J . l i n e a r i s (Cauro, 1958), U. and JJ. a r a s a k i i (Chihara, 1968,  1969).  A f t e r germination  entiates into an upright filament and a basal disk.  scagelii  the germling  differ-  In most species the  up-  r i g h t filament develops p r i o r to the basal disk, but i n U. g a y r a l i i , J J . l i n e a r i s (Cauro, 1958) velops f i r s t .  and J J . s c a g e l i i (Chihara, 1968)  the basal system de-  However, the r e l a t i o n s h i p between the two may  culture conditions (Cauro, 1958;  Baudrimont, 1961).  undergoes longitudinal d i v i s i o n s  1  tubular, monostromatic germling  ( L ^ v l i e , 1964).  be influenced by  The upright filament  at r i g h t angles to the surface to form a Eventually the tube collapses  producing a flattened distromatic blade (see F i g . 50c).  D i f f e r e n t species can  be d i f f e r e n t i a t e d by the length of the filament when the f i r s t longitudinal d i v i s i o n occurs, the persistence of the a p i c a l c e l l , and the morphology of the juvenile blade (Foyn, 1955;  1  B l i d i n g , 1968).  Recent studies have shown that  longitudinal d i v i s i o n s refers to the d i r e c t i o n of cleavage during cytokinesis.  24 germling morphology may vary greatly i n culture, p a r t i c u l a r l y when grown axenically (Prova.soli, 1958; Bonneau, 1977). In the northeast P a c i f i c only four species have been studied i n culture: U. lobata (Strand e t a l . , 1966), U. fenestrata and U. s c a g e l i i (Chihara, 1968), and U. taeniata  (Provasoli, 1961).  25 III. MORPHOLOGICAL AND ANATOMICAL VARIATION A.  METHODS 1.  Collections and Herbarium Studies  To determine the distribution and geographic variation of Ulva spp., general collections were made along the Pacific coast from northern British Columbia to southern California (Fig. 2).  In addition to these collections  large numbers of herbarium specimens, including many of the type specimens, from the northeast Pacific (defined for this study as the coast from the Aleutian Islands, Alaska,to the southern tip of Baja California, Mexico) and other areas were borrowed and studied (Table 4).  These herbarium specimens  provided valuable information regarding geographic and seasonal variation as well as being helpful in interpreting species descriptions and published distributions.  Diagnostic characteristics such as size, shape, blade thickness,  c e l l dimensions, pyrenoid number and the presence or absence and length of teeth were compared for specimens from different geographic localities. For microscopic observation of herbarium specimens, small pieces of blade were allowed to soak in seawater for 5 to 15 minutes.  Thickness and c e l l dimen-  sions were measured with an ocular micrometer at lOOOx power. Specimens resulting from personal collections were placed in the University of British Columbia Phycological Herbarium (UBC). In addition to the geographic collections, seasonal collections were made over several years in Barkley Sound on the west coast of Vancouver Island, B.C. (Fig. 3).  This large sound offers a wide variety of marine ha-  bitats as well as research f a c i l i t i e s at the Bamfield Marine Station (Western Canadian Universities Marine Biological Station). Of the 12 species of Ulva in the northeast Pacific, 6 have been reported from Barkley Sound (Scagel, 1973). During the f i r s t year of the study different morphological types  Table 4. Herbaria from which specimens were borrowed and studied. AHFH AKU  • -  Allan Hancock Foundation, University of Southern California, Los Angeles Auckland University (New Zealand)  CANTY  -  Canterbury Museum, Christchurch (New Zealand)  DS  -  Dudley Herbarium (in UC)  GJH  -  George J. Hollenberg (now in US)  GMS  -  Gilbert Morgan Smith .Herbarium (Hopkins Marine Station of Stanford University)  L  -  Rijksherbarium, Leiden University  LD  -  Institute of Systematic Botany, Lund  LE  -  Komarov Botanical Institute, Leningrad  MLML  -  Moss Landing Marine Laboratory of the California State Universities  M  -  Missouri Botanical Garden (specimens in UC)  NY  -  New York Botanical Garden  OSU  -  Oregon State University, Corvallis  PBA  -  Phycotheca Boreali-americana (in AHFH, UBC, UC, US; Collins et a l . , 1895-1919)  RS  -  Private Herbarium of Robert Setzer  UBC  -  University of British Columbia, Vancouver  UC  -  University of California at Berkeley  US  -  United States National Herbarium, Smithsonian Institute, Washington, D.C.  UW  -  University of Washington, Seattle  VJC  -  Private Herbarium of V. J . Chapman  Ehroughout this thesis numbers starting with (U) indicate personal collections from a given population on a given day.  lr  27  Figure 2.  Map of study area in the northeast Pacific. Open circles indicate locations of intertidal transects. Dots indicate collection sites.  28  29  Figure 3.  Map of study area in Barkley Sound, Vancouver Island. Arrows indicate locations of intertidal transects. • = hydrographic stations. • = Bamfield Marine Station.  31  Figure 4.  Aerial photographs of transect sites i n Barkley Sound (indicated by arrows). Obtained from the Department of Lands, Forests, and Water Resources, B.C. Government, a. Kirby Point, Diana Island (BC 7238-182). b. Scott's Cove (BC 7238-285). c. Grappler Inlet (BC 7261-055). d. Brady's Beach (BC 7707-052).  32  33 were collected from a variety of habitats and compared. During this i n i t i a l period, several trends in seasonality and morphological variation were noted. Further studies were conducted to confirm these trends and isolate the causal factors. 2.  Intertidal Transects  Four different transects perpendicular to the shoreline were established to determine the morphological and anatomical variation of Ulva fenestrata with vertical position and exposure to wave action.  Three sites were chosen  in Barkley Sound on the basis of accessibility by boat, exposure to wave action and abundance of U. fenestrata (Fig. 3,4; Table 5).  A fourth transect  was located at Brockton Point in Stanley Park, Vancouver. Permanent base points were placed by d r i l l i n g holes with a gas-powered impact d r i l l and sinking %" starbolts. The vertical positions of the base points relative to the lowest low water level (chart datum) were determined by comparing the water level at each transect with that at the tide gauge in front of the Bamfield Marine Station by means of shortwave radios.  The vertical  positions of two base points (Kirby Point, Brockton Point) were determined from predicted water levels (Canadian Hydrographic Service, 1974). Meter marks along the transect lines were surveyed to the nearest tenth of an inch (2.54 mm)  relative to the base points. 2  Specimens were collected from \ m  quadrats every meter (every 5 meters  for Brockton Ppint) along the transect lines. the quadrat was placed on the meter marks. of the blades were measured.  The center of the top edge of  In the lab the length and width  In most.instances disks were cut from the  center, and in larger t h a l l i from the margins, and preserved in 5% Formalin to be sectioned later.  Thallus thickness, c e l l dimensions and pyrenoid num-  bers were determined under lOOOx power.  Table 5.  Locations, dates and physical parameters of Ulva transects,  Location  Species Collected  Date  Brockton Point, Burrard Inlet, B.C. 49°18'N,123 07'W  U. fenestrata  25-VTI-76  U. scagelii  24-XI-76  Grappler Inlet, Barkley Sound, B.C. 48°49.92 N,125°06.94'W  U. fenestrata  22-VII-75  Slope -o  Exposure to Wave Action  boulders, shell, sand, mud  protected  11o  bedrock, boulders shell, sand, mud  protected  26o  bedrock  semiprotected  24  bedrock  semiexposed  sand beach, scattered boulders  semiexposed  2-XII-75  ,  Substrate  17-IV-76 Scott's Cove, S.W. of Aguilar Point, Barkley Sound, B.C. 48°50.07'N,125°08.7 W  U. fenestrata  North side of Kirby Point, Barkley Sound, B.C. 48°50.99'N,125° 11.97'W  U. fenestrata  21-VTI-75 2-XII-75  ,  ll-VTI-75  L  2-XII-75 16-X-76 16-IV-76  Brady's Beach, Barkley Sound, B.C. 48°49.74'N,125°09 W ,  U. taeniata  16-IX-74 31-XI-74 23- 11-75 ll-V-76 13-V-76 16-VI-76 27-VTI-76  •e-  35 To measure the yearly accumulation and loss of sand around a bed of Ulva taeniata on Brady's Beach, Barkley Sound, horizontal and vertical transects were surveyed periodically over a two year period relative to a permanent base point (Fig. 3,4d; Table 5). The vertical ranges of U. taeniata and other dominant algae were noted, and collections of U. taeniata were made every 5 meters along a 30-meter vertical transect.  As with U.  fenestrata these specimens were measured and sectioned. 3.  Hydrographic Data  Water temperature and water samples were taken from the surface and a depth of 3 meters during the daytime low and high tides every week or two weeks at two stations for a period of a year.  The stations were located at  the mouth of Bamfield Inlet and toward the head of Grappler Inlet (Fig. 3). The salinity of the water samples was measured with either a conductivity meter or a refractometer.  The purpose of these stations was to determine  i f differences i n salinity and temperature could account for some of the differences i n morphology and thickness between plants i n Grappler Inlet and plants from other areas.  36 B.  HYDROGRAPHY OF STUDY AREA During the summer months surface water temperatures and salinities  along the west coast of North America are influenced by the south flowing California Current and upwelling.  The California Current carries cold sub-  artic water from the Aleutian Current to as far south as 23° N where i t converges with the Equatorial Current (Sverdrup et a l , 1942). As they flow south the surface waters gradually increase i n temperature.  However, i n the  spring and early summer upwelling i s a. common phenomenon along the coast of California and in areas of Baja California, Mexico, resulting i n relatively cold coastal water.  This summer upwelling may be due in part to the north-  west winds prevalent i n the early summer or due to entrainment of water by the California Current (Emery, 1960). At Point Conception, California, the California Current encounters a northward flowing water mass and turns away from the coast to flow southwest (Emery, 1960). This results in an abrupt change of summer surface temperatures that is reflected by a change i n the marine flora i n southern California (Abbott and Hollenberg, 1976).  In the  f a l l and winter upwelling diminishes and a countercurrent, the Davidson Current, carries southern waters along the coast as far north as 48° N (Sverdrup et a l . , 1942). These two currents and upwelling provide the coast north of Point Conception with relatively cold surface temperatures. temperatures  The mean surface  from the Aleutian Islands to Point Conception range from 2° to  11.5° C in February and 9.5° to 15° C in August (U.S. Dept. of Commerce, 1956).  South.of Point Conception the surface temperatures range from 10° C  in January to 25.5° C in August with means of ca. 13.5° and 19.5° C (U.S. Dept. of Commerce, 1956). However, i n Baja California pockets of cold upwelled water provide surface temperatures comparable to temperatures north of Point Conception (McEwen, 1916). The flora of these areas of upwelling  37 include species more typical of northern waters (Dawson, 1946a, 1950, 1951). In the Strait of Georgia and in many of the inlets along the mainland coast of British Columbia, salinities and to a smaller degree temperatures are influenced by freshwater runoff with salinities varying from zero to that of open ocean waters (Pickard, 1961).  Salinities vary seasonally with the  lowest salinities occurring i n the winter during peak coastal precipitation and in the summer following snowmelt (Tully and Dodimead, 1957).  In the  central part of the Strait of Georgia the discharge of the Fraser River has a major influence on surface salinities.  At the mouth of Burrard Inlet  (Vancouver) the surface salinities vary from 10%. to 26%. (Tully and Dodimead, 1957).  Surface water temperatures i n the Strait of Georgia near the  mouth of the Fraswer River range from 5  to 16  C (Waldichuk, 1957).  Along the west coast of Vancouver Island river runoff also has a significant influence on the surface salinities of some inlets (Pickard, 1963). However, the salinities i n these inlets are generally greater than that i n the mainland inlets due to the relatively small river runoff on Vancouver Island. 1.  Salinity and Temperature Measurements i n Barkley Sound  Figure 5 shows the seasonal variation in salinities and temperatures from the two stations monitored i n Barkley Sound.  Salinities fluctuated dra-  matically, particularly at the surface between the months of September through April.  In Grappler Inlet salinities at the surface dropped on several occa-  sions to less than 5%« . However, these dramatic drops always followed heavy rainfalls.  At a depth of 3 meters salinities were less affected by rainfall  and were similar for both stations.  These data show that Grappler Inlet i s  not normally brackish except at the surface following heavy rainfalls.  Water  temperatures varied seasonally with a maximum temperature around 17°C i n summer and minimum temperature around 7°C i n winter and early spring.  38  Figure 5.  S a l i n i t y (a,b) and temperature (c,d) at the surface and a depth of 3 meters at two stations i n Barkley Sound between May, 1975, and May, 1976. a,c. In front of the Bamfield Marine Station. b,d. Grappler I n l e t . Dots and open c i r c l e s represent the averages between readings taken during the daytime hightides and lowtides on a given day at the surface (dot) and at a depth of 3 meters (open c i r c l e s ) .  40 C.  RESULTS Maximum, minimum and mean values of thallus thickness, c e l l dimensions  and pyrenoid number for specimens' of Ulva and Chloropelta caespitosa from the northeast Pacific are given i n Table 6. Although U. expansa, U. lobata ' and U. rigida are reported i n the literature (Table 3) for British Columbia, these species could not be distinguished from the different morphological types of U. fenestrata. The herbarium specimens of U. expansa and U. lobata from California also resembled U. fenestrata, but were kept separate for comparative reasons.  Herbarium specimens from the northeast Pacific identified  as U. lactuca were closer to other Pacific species of Ulva than to the European concept of this species (Bliding, 1968).  In almost a l l instances  these specimens were grouped and studied with other species. The study of herbarium specimens and f i e l d collections revealed a large degree of morphological and anatomical variation for distromatic ulvaceous algae i n the northeast Pacific.  A few species, such as U. stenophylla, U.  taeniata and Chloropelta caespitosa, were morphologically distinct, though in some instances they showed some variation with environmental factors. Other species showed similarities to each other and could not be easily distinguished.  Throughout this thesis species that appear to be related  w i l l be discussed together. 1. Ulva californica, Ulva scagelii, Ulva angusta Specimens f i t t i n g the description of Ulva californica were collected at several localities i n southern California.  These plants formed dense tufted  mats on top of rocks i n the mid to upper intertidal zones.  Individual plants  were small, less than 2 cm t a l l , and cuneate, but were often attached together by a common base giving a characteristic tufted appearance (Fig. 6). Ulva scagelii i n British Columbia was also found primarily i n the mid to upper  Table 6.  Blade thickness, cell dimensions i n transverse section and the number of pyrenoids per c e l l i n herbarium specimens of Ulva and Chloropelta (thickness and cell dimensions i n ym). Means are not given for fewer than 10 measurements. CENTER OF BLADE  U. angusta  1  MARGIN OF BLADE  Thickness  Cell Height  Cell Width  Thickness  Cell Height  Cell Width  Pyrenoid:  range  range  range  range  range  range  range  X  X  13-19  39-51  X  X  x  X  5-14(33)  32-45  (3)12-16  4-13  l(-2)  25-40  10-16  3-15  1("2)  20-60  10-22  4-13  l(-2)  U. californica (California)  25-70  42  10-22  14  5-21  U. scagelii (British Columbia)  27-63  42  7-23  17  5-25  Brockton Pt.  30-81  46  11-32  18  Grappler Inlet  29-90 48  8-39  16  4-25  15  23-58  32  7-27  12  5-20  10  1-3(4)  Bamfield Inlet  36-100 70  15-40  25  6-26  13  36-69  50  15-24  19  6-25  14  1-3(4)  Scott's Cove  31-87  55  10-37  21  5-24  12  Kirby Pt.  34-100 59  13-43  24  4-28  11  U. expansa (California)  . 46-105 71  16-41  28  U. lobata (California)  51-106 77  23-53  U. r i g i d a  48-105 74  19-32  10  U. fenestrata  2  20  1-2(3,4)  23-60 41  1-3(4) 44-69  54  6-21  30-69  44  5-24  35-81  8-28  3  15  43-78  56  1-3(4) 12-14(30)  6-15  1-2(3)  14-40  4-24  1-3  18-24  5-28  1-3  Table 6. Continued.  MARGIN OF BLADE  CENTER OF BLADE Thickness  Cell Height  Cell Width  Thickness  Cell Height  Cell Width  range  range  range  range  range  range  x  U. conglobata  53-97  15-40  U. stenophylla  38-136 67 (180)  17-35  x  x  5-22 26  7-34  14  x  x  x  4-24  Pyrenoids range  40-64  13-19  1-3(4)  28-47 42  12-24  17  7-34  13,  1-3(4)  34-52  9-19  16  7-24  13  1-4(5-7)  33-64 43  14-24  19  6-22  12  1-3(4-6)  39-78 53  11-35  21  7-30  13  1-3(4-7)  U. taeniata British Columbia Oregon and Calif, north of Pt. Conception South of Pt. Conception U. fasciata Chloropelta caespitosa  40-90  57  14-35  24  6-26  15-38  27  6-25  14  41-214 122  13-78  43  . 5-30  16  82-100  37-43  10-15  85-88  32-43  7.5-12  several  23-60  6-17  6-25  17-35  6-19  6-19  1-2(3)  Dentate specimens. Many of these specimens had eroded margins.  3  14  37-116 76  *Type material. 2  42  43  Figure 6.  Herbarium specimens of Ulva califomica and specimens morphologically intermediate between U. califomica and U. scagelii a. From Botany Beach, Port Renfrew, Vancouver IsT., B.C. (U308; ll-VTI-76). b. From San Gregorio Beach, Calif. (U266.5; 31-XII-75). -c. From Point Joe, Calif. (U303; ll-VII-76). d. From Maiibu, Calif. (AHFH 63053; 17-XI-56). E. From Point Mugu, Calif. (AHFH 66940; 26-X-57). f. From La Jolla, Calif. (NY; Lectotype of U. califomica; no date of c o l l . ) . a-c,e. Scale bar = 50 mm. d,f. Scale bar = 5 mm.  44 a  (  f V  5  CM  V  45  Figure 7.  Herbarium specimens of Ulva scagelii from British Columbia and Washington, a. From Kitsilano Beach, Vancouver (Isotype; UBC 34570; 29-VII-68). b. Victoria breakwater, Vancouver I s l . (UBC 18431; 23-V-63). c. West side of Whidbey I s l . , Puget Sound, Wash. (U336; 23-VII-77).  47  intertidal zones, often forming mats with up to 100% cover.. However, individual plants were solitary rather than tufted, cuneate to narrowly oblanceolate and up to 20 cm or more i n length (Fig. 7). Transitional specimens were encountered on the west of Vancouver Island (Fig. 6a) and i n central and southern California (Fig. 6b-e).  These transitional specimens could  not be identified with certainty with one or the other species. Thallus thickness and c e l l dimensions were similar for both species (Table 6) and could not be used to separate morphologically transitional forms.  In both species the cells i n transverse section were isodiametric  to slightly taller than wide in both the center and margins of the blade (Fig. 8f~h).  In many specimens the blade tapered to a short stipe-like  base that was e l l i p t i c a l in transverse section due to the presence of r h i zoidal protuberances between the c e l l layers.  In other specimens rhizoidal  cells originated at the base of the flattened blade (Fig. 8b,e).  In surface  view the cells of both species were 4~6 sided, rectangular, angular or with rounded corners (Fig. 8a,c). The cells often formed short longitudinal rows. Most cells had 1 pyrenoid per c e l l , though 2 pyrenoids were observed in some cells of several specimens. No specimens were encountered while collecting or in herbaria that could with confidence be identified as U. angusta Setchell et Gardner, other than the type material.  Most herbarium specimens labeled as such were found  on examination to be U. taeniata (e.g. AHFH69365, US39015) or U. stenophylla (GMS8018). The type specimens are narrowly oblanceolate with ruffled margins (Fig. 9) and are similar i n thickness, c e l l dimensions and pyrenoid number to specimens of U. californica and U. scagelii (Table 6; Fig. 8d,i). Figure 10 shows the relationships between blade length and width, and blade length and geographic distribution for a l l three species.  48  Figure 8.  Surface and sectional micrographs of Ulva californica from southern California, U. scagelii from British Columbia and U. angusta (Isotype material). a. Surface view of U. californica. b,c. Base and central surface view of~U. scagelii! d. Central surface view of U. angusta. e,g. Transverse sections through the basal rhizoidal region and above the rhizoidal region in U. californica. g,h. Central and margin transverse sections of U. scagelii. i . Marginal transverse section of U. angusta. a. Scale bar = 50 um. f. Scale bar = 100 um- b-e,g-i. Same scale bar as (a). P = pyrenoid. R = rhizoidal region.  t b  f  50  Figure 9.  a,b. Isotype material of Ulva angusta. a. US 57109 b. AHFH 60478. c. SpecimerToF U. californica (U266.5) grown in culture.  52  Figure 10. a. Relationship between blade length (cm) and blade width (cm) in herbarium specimens of Ulva californica, U. scagelii and U. angusta. b. Relationship between blade length (cm) and l a t i tude m herbarium specimens of U. californica and U. scagelii. Each dot or circle represents measurements from a single ~ specimen. Open circles indicate type material. Uc = U. californica. Us = U. scagelii. Ua = U. angusta.  54 2.  Ulva fenestrata, Ulva expansa, Ulva lobata  Numerous specimens, from Alaska to southern California were encountered that were orbicular, lobed or expanded. These specimens varied considerably in morphology, blade thickness, c e l l dimensions and pyrenoid number, and formed a continuum that could not be clearly broken down into species (Figs. 12-14). Herbarium specimens from California had generally been identified as U. expansa, U. lobata, U. lactuca and U. rigida.  In Oregon, Washington,  British Columbia and Alaska most of these had been identified as U. fenestrata, U. lactuca and U. rigida.  As shown in Figure 1 these species were  separated by thickness, blade morphology and the presence or absence of perforations.  Figure 11 shows the type specimens of some of these species.  I n i t i a l field collections indicated that the variation of these specimens reflected environmental differences. Large expanded plants, that reached lengths of up to 1.5 meters, were encountered primarily in relatively protected shallow bays and inlets.  Thick, lobed plants usually occurred in the  mid to lower intertidal zones in areas of moderate wave exposure (Fig. 12c,d). In these same areas plants in the upper intertidal zone were orbicular and relatively thin.  Along open coast beaches t h a l l i in the mid to upper inter-  tidal zones were small, thick and densely tufted (Fig. 12b).  Many plants  were observed to have numerous perforations, a feature considered diagnostic for U. fenestrata (Fig. 13).  Perforations were more common in specimens in  the northern part of the study area; however, many specimens from California were also perforate.  These perforations appeared to be cause by grazing or  abrasion in most instances.  Specimens that were attached to floats or  Nereocystis stipes always lacked perforations (Fig. 12a). To determine i f environmental factors related to vertical position and wave exposure could be responsible for part of the observed variation, several transects were established in Barkley Sound and one at Brockton Point  55  Figure 11. Type material of lobed and expanded species.of Ulva. a. U, fenestrata (Holotype; LE; photograph i n UBC). b. U. fasciata f. expansa (Holotype; UC 98481). c. U. fasciata f T lobata (Holotype; UC 98491). d. Phycpseris Tobata Lectotype; L4114-3; Specimen illustrated by Kiitzing (1857)).  57  Figure 12. Lobed and expanded specimens of Ulva from the northeast-Pacific, a.. Specimen attached to a Nereocystis stipe, Barkley Sound, Vancouver I s i . (UBC 58337 (U283); 13-V-76). b. High intertidal specimen from an exposed beach, Moss Landing, California (U194; 27-IV-76). c,d. Low intertidal specimens, c. Aguilar Point, Barkley S., Vancouver I s i . (UBC 58101 (U60); 27-VI-73). d. Scott's Cove, Barkley S., Vancouver I s i . (UBC 58338 (U138b); 15-IX-74). a,c,d. Scale bar = 100 mm. b. Scale bar = 50 mm.  58  59  Figure 13.  Lobed and expanded specimens of Ulva from the northeast Pacific several of.which show varying degrees of perforations., a-^-c, U. fenestrata.. d. Expanded perforate specimen of U. scagelii identified by its^developmental pattern i n culture, a. Grappler Inlet, Barkley S., Vancouver I s i . (UBC 58305; 23-11-75);. b. Yaquina Bay, Oregon (OSU 21; 9-IX-65).. c. Yaquina Bay, Oregon (OSU 1000). d. Grappler Inlet, Barkley S., Vancouver I s i . (UBC 58304; 23-11-75). a-d. Scale bar = 100 mm.  61  Figure 14.  Surface and sectional micrographs of Ulva fenestrata and related species from the northeast Pacific, a-c. Surface views of the central area of the t h a l l i . d. Marginal surface view. e. Surface view of "U. conglobata.',' f-h. Central transverse sections of herbarium specimens identified as U. fenestrata (f) U. expansa (g) and U. lobata (h). i . Transverse section.near margin i n U. fenestrata. j,k. .Central and marginal transverse sections oT "U. conglobata." a. Scale bar = 50 um. b-k. Same scale as (a).  6 2  •it. 3  C ^»  —  »  63  in Burrard Inlet.  Table 5 gives the sampling dates, slope, substrate and  exposure of each transect.  I n i t i a l l y i t was hoped that seasonal data could  be collected from the transects, but the patchy distribution and general sparseness of Ulva in the winter months made i t impossible to collect quantitative data year round. Although a large amount of variation was encountered in each quadrat along the transects, there was in most instances a significant increase in size (Table 7; Fig.,15) and thickness (Table 8; Fig. 16) of t h a l l i the lower the quadrats were located in the intertidal zone.  Comparisons of the three  Barkley Sound transects showed that the upper limit of Ulva was depressed in sites less exposed to wave action, and that the thickness of t h a l l i decreased at a given vertical level in the less exposed sites (Table 8; Fig. 16).  Figure 17a shows these three transects graphed against percent time  exposed to a i r calculated from the tide level predictions for Bamfield Inlet for the 4 week period prior to sampling along the transects. A change of shape and in some instances coloration was also observed along the transects.  In those exposed to surf or swells (Kirby Point, Scott's  Cove) t h a l l i in the mid to upper intertidal zones tended to be small, and orbicular or ovate, often with ruffled margins (Fig. 18a).  Thalli in the  mid to lower intertidal zones became increasingly more lobed and expanded (Fig. 18b-d).  Lobes appeared to result from uneven growth along the margins,  often initiated by tears in the blade.  In some instances s l i t s in the middle  of a blade resulted in a lobe overlapping the blade.  In the two sheltered  transects (Grappler Narrows, Brockton Point) t h a l l i in the upper intertidal zone were often pale in coloration, soft in texture, tattered and heavily epiphytized.  Plants toward the lower end of the transects were increasingly  darker green, firmer, less epiphytized and more lobed in appearance.  No  correlation could be made between perforations and vertical position or wave  64  Table 7. .Comparison of thallus length (cm) in transect samples showing the number of measurements.(n), the means (x),. standard deviations (SD), and the value.of "student t."_ Significant (t) values indicate that the ..null hypothesis ( x ^ x„) .is false. The vertical position.of the samples i n meters above chart datum i s also given (H). Upper most sample = (U); lower most sample = (L). H  n  X  SD  t  significance  Kirby Point (ll-vTI-75) 2.13  36  5.35  2.23  1.7  46  7.79  2.90  1.27  82  10.01  4.54  0.74  25  15.88  10.15  0.38  32  21.25  13.30  4.20  highly sign P<.01  4.95  II  I I  11  4.84  II  I I  11  1.68  not sign '.-  P:>.05  0.09  not sign  P>.05  Scott's Cove (21-VII-75) 2.49  22  6.00  2.54  1.39  4  6.12  1.93  0.84  10  7.35  4.02  0.61  22  9.45  6.30  0.28  12  15.33  8.85  (U)  2.49  2.54  (L)  0.28  8.85  0.85  11  11  0.96  11  Tl  2.25 4.66  sign  P<.05  highly sign P<.01  Grappler Inlet (22-VII-75) 1.74  „8  6.47  3.45  1.44  7  6.43  3.78  1.20  8  7.50  3.69  19  7.96  5.95  0.30  8  9.71  4.04  0.06  8  19.62  0.44  —  not sign  P>.05  sign  P<.02  not sign  P>.05  13.44  (U)  1.74  3.45  (L)  0.06  13.44  2.68  Brockton Point (5-V-77) 3.23  9  4.04  1.94  2.74  5  7.14  4.35 •  2.41  .9  4.00  1.03  2.00  .7 '  7.07  3.35  7.25  2.72  1.49  4  11  tl  II  11  11  11  65  Table 7. Continued. H  n  x  SD  1.49  4  7.25  2.72  1.03  12  ;7.52  0.68  15  7.26  4.92  0.60  10  10.93  9.74  "  t  3.95  (U)  3.23  1.94  (L)  0.60  9.74  "  significance  n  o  t  s i g n  P >  -  0 5  ~ '  2  '  0 8  p<  -- 10  Brady's Beach (16-VT-76)  (U) (L)  1.22 1.0  7 5  3.52 4.34  1.14 3.15  0.91.  12  15.57  5.81  0.73  7  24.60  8.50  0.05  6  23.00  10.82  1.22 0.73  1.14 10.82  "  not sign  "  "  6.02  P>.05  highly sign P<.01  66 Table 8. Comparison of thallus thickness (um) i n transect samples showing the number of measurements.(n), the means (x), standard deviations (SD), and the value of "student t."_ Significant (t) values indicate that the null hypothesis (x,= x„) i s false. The vertical position of the samples in meters above chart datum i s also given (H). Upper most sample = (U); lower most sample = (L) H Kirby Point  n  X  SD  t  significance  (ll-VTI-75)  2.13  34  53.5 .  5.6  1.7  45  59.0  7.7  1.27  29  64.0  10.4  0.74  24  71.2  9.5  0.38  31  79.6  11.9  8.8  3.51  sign  F<-v01  2.39  sign  P<.05  2.62  sign  P<.02  2.82  sign  P<.01  2.38  sign  P<.05  0.39  not sign  P>.05  1.22  not sign  P>.05  2.87  sign  P<.01  0.59  not sign  P>.05  1.59  not sign  P>.05  2.88  sign  P<.01  Scott's Cove (21-VTI-75) 2.49  18  40.2  1.39  4  51.2  0.84  10  53.4  10.12  0.61  17  59.0  12.26  0.28  12  71.2  9.63  6.18  Grappler Inlet (22-VTI-75) 1.74  8  32.6  3.7 .  1.44  7  31.6  2.9  1.20  8  39.2  10.7  0.30  21  53.0  11.7  0.06  8  73.0  9.15  4.32  highly sign P<.01  1.18  not sign  P>.05  1.00  not sign  P>.05  2.73  sign  P<.02  Brockton Point (5-V-77) 3.23  9  '38.0  6.6  2.74  5  42.6  7.61  2.41  9  39.8  2.98  2.00  7  35.3  3.63  1.49  4  37.0  1.82  0.86  not sign  P>.05  1.03  12  42.4  10.22  1.03  not sign  P>.05  0.68  15  56.5  11.64  3.29  sign  P<.01  0.60  10  62.2  12.74  1.15  not sign  P>.05  4.74  highly sign P<.01  (U)  3.23  6.6  (L)  0.60  12.74  67  Figure 15. Relationships of blade length (cm; dots) and.blade width (cm; open circles) with vertical position (m) above chart datum i n Ulva fenestrata along three intertidal transects i n Barkley Sound (a-c) and one in Burrard Inlet (d). a. Kirby Point; ll-VII-75, 16-IV-76. b. Scott's Cove; 21-VII-75. c. Grappler . Inlet; 22-VTI-75. d. Brockton Point; .5-V-77. Each dot or circle represents the mean of 4~82 measurements of specimens collected in % m quadrats. Refer to Table 7. 2  oo  69  Figure 16. Relationship between blade thickness (pm) and vertical position (m) above chart datum in Ulva fenestrata along three intertidal transects in Barkley Sound (a-c) and one in Burrard Inlet (d). a. Kirby Point; ll-VTI-75, 16-IV-76. b. Scott's Cove; 21-VTI75. c. Grappler Inlet; 22-VII-75. d. Brockton Point; 5-V-77. Each dot represents the mean of 4~45 measurements of specimens collected i n % m quadrats. Horizontal bars represent standard deviations of the means. Refer to Table 8. 2  71  Figure 17.  a. Relationship between blade thickness (um) of Ulva fenestrata along three intertidal transects perpendicular to the shoreline and time exposed to a i r calculated from the predicted tide level (Canadian Hydrographic Service, 1974). Kirby Point, ll-VTI-75; Scott's Cove, 21-VTI-75; Grappler Inlet, 22-VTI-75. b. Percentage of specimens of U. fenestrata with one pyrenoid per c e l l and percentage'with 2-4 pyrenoids per c e l l at .different vertical positions above chart datum along an intertidal transect (Kirby Point; ll-VII-75). Refer to Table 8.  72  73  Figure 18.  Changes i n morphology.of Ulva fenestrata along a vertical transect.(Kirby Point). a. 1.7 meters above chart datum, b. 1.2 m. c. 0.75 m. d. 0.3 m.  74  75 action. Changes in thickness were reflected by changes of c e l l height in sectional view; however, other c e l l dimensions showed no observable relationships to vertical position or wave exposure.  The pyrenoid number tended  to increase slightly with a decrease of vertical position in the intertidal zone (Fig. 17b). 3.  Ulva rigida  Specimens from southern California and Baja California were encountered that f i t the description of U. rigida sensu Bliding (1968). These plants formed tufts or turfs in the mid to upper intertidal zones, sometimes mixed with Chloropelta or occasionally Ulva califomica.  However, thallus shape,  size, thickness, c e l l dimensions and marginal microscopic dentation made these specimens easy to separate from Chloropelta and U. califomica (Table 6; Fig. 19).  Specimens of U. rigida from southern California were usually  irregularly lobed and up to several cm t a l l (Fig. 19a).  North of Point  Conception only one broadly lobed specimen was observed that had dentation along the margins (Fig. 19d).  Several collections were made i n northern  California, Oregon and British Columbia of nondentate densely tufted t h a l l i growing in exposed locations in the upper intertidal zone (Fig. 12b).  These  plants f i t the description of U. conglobata form densa Kjellman which Yendo (1916) and Setchell and Gardner (1920b, p. 270) considered to be a form of U. rigida.  Specimens of U. rigida from southern California and U. conglobata  from north of Point Conception both occasionally showed a difference in c e l l height in,the two c e l l layers when collected from the upper intertidal zone in exposed areas (Fig. 14j). However, this differentiation of c e l l layer was also found i n specimens more typical of U. fenestrata.  76  Figure 19.  Morphology and anatomy of Ulva rigida from the northeast Pacific. a. Herbarium specimens from Pacific Beach, Calif. (U293; 26-V-76). b-d. Central (b) and marginal surface views. e,f. Central transverse sections. g,h. Marginal transverse sections, a. Scale bar = 50 mm. b. Scale bar = 50 um. e-h. Same scale as (b). c. Scale bar = 50 um. d. Same scale as (c).  77  .78 4. Ulva stenophylla Ulva stenophylla was found to be one of the most' distinctive species of Ulva in the northeast Pacific.  Specimens were relatively uncommon and were  found from Barkley Sound, B.C.,to Santa Barbara, California.  Thalli were  simple or occasionally lobed, linear, lanceolate, narrowly e l l i p t i c a l or rarely oblanceolate (Fig. 20).  Young t h a l l i were planular throughout but later  usually developed ruffled margins, leaving a planular central axis 0^5 to 3.5 cm wide, as well as becoming spirally twisted.  The blade tapered abrupt-  ly to a short flattened cuneate base, occasionally with a short cylindrical stipe in young plants.  Thalli reached lengths of nearly two meters and were  usually 2 to 26 times longer than wide (Fig. 22a). As can be seen from Table 6 and Figure 21f-l the central axis of most specimens was relatively thick compared to the margin.  In the thicker speci-  mens cells of the central axis were characteristically bullet-shaped, tapering toward the blade surface (Fig. 21f).  In surface view cells along the central  axis were rectangular to polygonal, or occasionally hemispherical with rounded corners, and in no observable order (Fig. 21b,d).  Cells along the margins  and i n the central area of young t h a l l i were rectangular or polygonal, often in curved rows (Fig. 21c).  Although Setchell and Gardner (1920a) reported  that U. stenophylla lacked pyrenoids, specimens, examined usually had 2-3 or more pyrenoids in each c e l l .  Examination of the type specimen (UC 98512)  revealed the presence of pyrenoids(Fig. 21d). In Barkley Sound U. stenophylla formed pure populations or was mixed with Enteromorpha linza, U. fenestrata or U. taeniata.  In the winter and  early spring only young plants were found attached to the stipes of Nereocystis luetkeana.  In the spring and summer U. stenophylla colonized the mid  intertidal to subtidal zones in moderately exposed (Brady's Beach) and protected areas (Grappler Inlet).  In the late f a l l this species was generally  79  Figure 20. Herbarium specimens of Ulva stenophylla. a. Epiphytic on Nereocystis, Scott's Cove, Barkley S., Vancouver I s l . (U324; 3-IV-77). b. From Cable Beach, Barkley S. (U132; 13-IX-74). From Bolinas, Calif. (UC 393944; V-03). d. From Monterey, Calif. (Isotype; UC 98511; 10-VT-Ol). a-d. Scale bar = 100 mm.  81  Figure 21.  Surface and sectional micrographs of Ulva.stenophylla. a-c. Surface views of the base (a), central axis (b) and margin (c). d. Surface view of the Holotype. Note the presence of pyrenoids (P). e - i . Transverse sections through the base (e), central axis (f,g) and margin (h,i). a. Scale bar = 50 ym. b - i . Same scale as (a).  82  • v.  .-i * ~ 4 ^  u  83  Figure 22. a. Relationship between blade length (cm) and blade width (cm) in Ulva stenophylla from Barkley Sound, b. Relationship between blade length (cm) and time of year in herbarium specimens of U. stenophylla from Barkley Sound. Each dot or circle represents measurements of a single specimen. Open circles indicate type material from Monterey, Calif. (UC).  LENGTH  LENGTH ro co o o 1 1  -i o J  A o 1  o  ui 1  o  o> s oo (O o o o 1—!__J___j  c cyJ  O _L_  M O _J_  o _L_  •IO _L_  (CM) cn O  co -si co co o o o o o o _L_  ro O  4O  o o  CO  o  •• •  •  © o  >-  •0  © © •© «  •  N  2 -  • 9  •  ©•  ©•• • •  •  • •  © •  ©  w  ©  •  ©  m  •»  ©&r«©  • ©9 •  •  • • © 6»  ••  © © © 0 •  >  ©•  ©••©•  %  w.  o O o O  °  <r 0  •  •  ©  o H  O  ••© © © © ©9©°  ro  zo-i  cr  CO  CO rs.  85 absent from Barkley Sound during the period of the study (Fig. 22b).  Like  U. fenestrata the length and thickness of the t h a l l i tended to increase with a decrease in vertical position; however, the patchy distribution of U. stenophylla made i t d i f f i c u l t to determine the degree of variation along a transect. 5-  No variation could be correlated with geographic distribution.  Ulva taeniata, Ulva costata, Ulva dactylifera, Ulva fasciata  Ulva taeniata, U. costata and U. dactylifera were found to be similar in morphology and anatomy.  Thalli of a l l three were linear to lanceolate,  simple, lobed or branched from the base into several narrow lacinae (Fig. 23, 29).  The blades were almost always spirally twisted and often had thickened  planular midribs or costae and thin ruffled margins. As can be seen i n Figure 30a for specimens of U. taeniata from Barkley Sound, specimens reached lengths of over 1.5 meters with length to width ratios of 2:1 to over 80:1. These morphologically and anatomically similar species were separated in the literature primarily by the presence of marginal teeth in U. taeniata (Setchell and Gardner, 1920b; Smith, 1944) and the presence of distinct "costae" in U. costata (Hollenberg, 1971; Abbott and Hollenberg, 1976).  Ulva  taeniata was usually reported to be distributed from southern British Columbia to just south of Point Conception (Abbott and Hollenberg, 1976).  South  df Point Conception U. taeniata was generally reported to be replaced by the nondentate species, U. costata and U. dactylifera.  However, herbarium stud-  ies, of a l l three species revealed dentation in most specimens with a decrease in the size of dentation south of Point Conception (Fig. 26a).  The decrease  in the length of teeth appeared td be related td an increase df surface water temperatures (Fig. 26a,c). 50 ym to over 1.5 mm.  Ndrth df Point Conception teeth ranged from about  In southern Califdrnia between Pdint Cdnceptidn and  the Mexican border, the teeth were much reduced or absent.  Blade thickness  86  Figure 23. Herbarium specimens of Ulva taeniata (a-c) and U. fasciata (d) from California, a. From Monterey (Isotype; US 57112; 11-VT01). b. From Loon Point, Santa Barbara Co. (AHFH 67481; 19-XII-57). Note pale and dark costae. c. Arroyo Sequit _ (AHFH 62940; 18-X-56). Note pale costae. d. Ulva fasciata from San Diego Bay (RS; 4-V-74). a,b,d. Scale bar = 100 mm. c. Scale bar = 50 mm.  88  v Figure 24. Surface and s e c t i o n a l micrographs o f Ulva t a e n i a t a and r e l a t e d species, a. Surface view o f a dark costa. b. Surface view o f a pale costa. c,d. Marginal surface views, e. C e n t r a l t r a n s verse s e c t i o n . f,d. Transverse sections through l a c i n a e showing the t r a n s i t i o n from the thickened midrib o r costa to the t h i n margin. Note r h i z o i d s between the c e l l l a y e r s i n ( f ) . h. Margin a l transverse s e c t i o n showing a tooth, i . Microscopic dentation i n the Holotype o f U. d a c t y l i f e r a (UC 205622). a. Scale bar = 50 um. b-c,e-j.h'. Same s c a l e as (a) d. Scale bar = 50 um. f. Scale bar = 100 um. g. Same s c a l e as ( f ) . i . Same s c a l e as (d). P = pyrenoid. R = r h i z o i d a l l a y e r .  89  90  Figure 25.  Morphology and anatomy of the type material of.Ulva fasciata f. costata. a,b. Lectotype (NY), c. Surface view of lacinae showing costae. d. Transverse section of transition area between costa and margin, e-g. Surface views of the costa (e), margin (f) and transitional area (g). c. Scale bar = 10 mm. d,e,g. Scale bar = 50 um. f. Same scale as (e).  92 of these species also varied with geographic distribution and appeared to be related to water temperature (Fig. 26b,d). The thickest specimens occurred in southern California and areas of Baja California that lacked upwelling. Cell width did not vary appreciably with geographic distribuiton. Many specimens, particularly those from southern California, had thick central costae that differed i n color from the margin.  In some the costae  were paler than the margin; i n others they were darker (Fig. 23a-c). In plants with pale costae the central cells contained large vacuoles (Fig. 24b). The pale coloration was due to the larger size of the cells and the greater distance between cells i n the costae relative to the margin (Fig. 24g). In most plants with dark costae the central cells were packed with starch granules (Fig. 24a).  In other plants a distinct dark costa was caused by a layer  of rhizoids between the c e l l layers that i n some instances extended to the tip of the lacinae (Fig. 24f). The type specimens of U. fasciata f. costata Howe (1914) from Peru had pale costae caused primarily by a change i n the dimensions of the cells (Fig. 25).  These specimens also had a dark band along  the margin caused by a shift in position of the chloroplast.  Specimens from  California previously identified as U. costata had costae that were darker than the margins (see Hollenberg, 1971, Fig. 1). Many specimens of U. taeniata and U. dactylifera from California and Baja California had either pale or dark costae to varying degrees. —  This included an isotype of U.  taeniata (US 57112; Fig. 23a) that had a pale costa. No correlation between morphology and the type of costae could be made. Two specimens from southern California (P.B.A. 221b at UBC; unnumbered specimen i n the Setzer Herbarium, Fig. 23d) were encountered that were closer to U. fasciata Delile than the three species discussed above. Both specimens were branched from the base into narrow planular lacinae that were approximately the same thickness along the margins as they were i n the  93  Figure 26. a. Relationship between length (0.1 mm units) of .marginal teeth and latitude i n herbarium specimens of Ulva taeniata. b. Relationship between blade thickness (um) and latitude in herbarium specimens of U. taeniata. a,b. Each circle represents the measurement of one specimen. c, d. Maximum (dots; average for August) and minimum (open circles; average for January) yearly surface water temperatures along the west coast of North America (McEwen, 1916; U.S. Dept. of Commerce, 1956).  LENGTH OF T E E T H  w  T o°0° o  o  •  o  V  1% O 0  (0.1 MM UNITS)  •  eaSw»S  o  •  oo  o  o  o  o  o  « o  41  u »  o  o  •  o  • o o  OO  o  Si  O  O O  O O O O O  o  fi>  T H I C K N E S S (UM)  I  8  O O  o o  o o Co cPoP o  o o  .  I  & o  •  oo  <98  oo ^  CO oo 0 o0 o N  o  • • coo o  o cooccoo o  o  76  o o  o<Pb 8  cPQoo O 1  0  «  o o  o  -  O^  O  o  95  Figure 27.  Photographs of Brady's Beach transect in.the late summer (a; 15-IX-74) and i n the winter (b; 22-11-75).  97  Figure 28.  a. Seasonal variation.in the height (m) of Brady's Beach relative to chart datum caused by the movement of .sand. Each point represents the average of six measurements along a a 30 m transect.. b. Relationship between blade length (cm) in Ulva taeniata and vertical position (m) above chart datum along a transect perpendicular to the waterline (Brady's Beach; 16-VI-76). Refer to Table 7.  98  0  5  10 BLADE  15 L E N G T H (CM)  20  25  99  Figure 29.  Winter (a,b) and summer (c,d) specimens of Ulva taeniata from Barkley Sound, a-c. From Brady's Beach. a7~UT53; 22-11-75. b. U268; 15-11-76- c. U124; l-IX-74. .d. From Second Beach (UBC 57975 (U246); 10-VII-75). a,b. Scale bar = 50 mm. C j d . Scale bar = 100 mm.  101  Figure 30.  a. Relationship between blade.length (cm) and blade width (cm) in herbarium specimens of Ulva taeniata from the northeast Pacific, b. Relationship between blade length (cm) and time of year i n U. taeniata from Barkley Sound. Each point represents the measurement of a single specimen.  LENGTH (CM)  LENGTH  (CM)  O o  NO  103 center (Table 6). Seasonal studies were made of U. taeniata in Barkley Sound. This relatively uncommon species was generally found attached to boulders or bedrock partially buried in sand along exposed and semi-exposed beaches. In areas U. taeniata formed dense beds mixed with Gracilaria verrucosa during the spring, summer and f a l l .  However, i n late f a l l and winter these beds  appeared to completely disappear, not to reappear again until spring (Fig. 27).  Surveyed transect lines demonstrated that over 30 cm of sand was de-  posited on Brady's Beach during f a l l and winter of 1974-5 covering rocks to which an extensive bed of U. taeniata was attached (Fig. 28a).  In the late  f a l l i t was not uncommon to find t h a l l i buried with as much as 15 to 30 cm of sand with just their tips protruding. However, in January and February even these plants disappeared.  On February 23, 1975 several boulders were  dug out of the sand, but no indications of attached t h a l l i or holdfasts could be found.  A search of the neighboring rocky headland revealed a much  reduced form of U. taeniata. These t h a l l i , though mature as indicated by their f e r t i l i t y , were only 3 to 5 cm long and irregularly lobed (Fig. 29a,b) but were easy to recognize by their distinct dentation. In spring as the sand receded, swarmers from these winter plants were probably responsible for recolonizing newly exposed rock surfaces. As can be seen in Figure 30b the length of U. taeniata t h a l l i from Barkley Sound increased over the summer reaching a peak i n early f a l l . Length also increased significantly with a decrease i n vertical position i n the intertidal zone along Brady's Beach (Table 7; Fig. 28b). 6. Chloropelta caespitosa Chloropelta caespitosa was f i r s t encountered while collecting IT. c a l i fornica and U. rigida in southern California.  This diminutive alga-was  104 distromatic and closely resembled Ulva morphologically and anatomically (Table 6; Fig. 31). However, i t s peltate blade and distinctly different ontogeny (Section IVB-2) set this alga apart from Ulva and other ulvaceous algae. Chloropelta caespitosa grew i n the upper intertidal region of exposed beaches attached to bedrock, boulders, cement blocks and kelp stipes (Fig. 31a,b). On sandy beaches the plants formed low densely tufted mats on emergent rocks; on rock benches plants attained a larger size and were loosely tufted.  Chloropelta caespitosa often grew mixed with U. califomica  and U. rigida, but i t was usually easily distinguished by i t s peltate blade (Fig. 31d-f).  Large specimens that had blades split to the base were more  d i f f i c u l t to separate from species of Ulva but could be identified by the circular rhizoidal zone at the center of the blade and the lack of marginal dentation (Fig. 31f,g).  Also the rhizoidal cells i n the blade appeared more  loosely organized i n Chloropelta (Fig. 31i). In addition to the collections made i n southern California, specimens of C. caespitosa were found i n collections of E. Yale Dawson deposited i n the Allan Hancock Foundation Herbarium (AHFH) at the University of Southern California (Section VTC-8). These specimens, previously identified as U. califomica by Dawson, were from southern California, between Los Angeles and San Diego.  105  Figure 31. Habit, morphology and anatomy of f i e l d specimens of Chloropelta caespitosa. a. Type locality (Point Fermin, San Pedro, Calif.), b. Habit, of plants from type locality (scale bar = 50 mm), c-g. Herbarium specimens, c. Type material (U286;.26-V-76; scale bar = 2.5 mm)., d. From La Jolla Cove, Calif. (U292;. 27-V-76; scale bar = 1 mm), e-g. From Laguna Beach, Calif, e. AHFH 64566; 14-1-57; Scale bar = 1 mm). f,g. UBC 57968, 57967; 26-V-76; Scale bar = 10 mm. h , i . Surface views of the center of the blade (h) and near the base ( i ) . j,k. Central and marginal transverse sections, h-k. Scale bar = 50 um.  106  107 D.  DISCUSSION As discussed in Section IIIB the ulvaceous algae are known to vary  considerably in their morphological and anatomical characteristics (Setchell and Gardner, 1903; Klugh, 1922; Bliding, 1938; Arasaki and Chihara,  1959;  van den Hoek, 1964; Chapman, 1964; Bliding, 1968; Kapraun, 1970; Steffensen, 1976a). This is also true for species of Ulva from the northeast Pacific (Table 6), though some of the variation can be related to environmental factors and is predictable. Variation with various environmental factors and the use of morphological and anatomical characteristics as taxonomic criteria are discussed below. 1.  Geographic Variation in Morphology and Anatomy  Morphological and anatomical changes with geographic location were particularly apparent in U. taeniata. The length of marginal teeth decreased and blade thickness increased the further south plants were collected.  Water  temperature appears to be a primary factor influencing these changes as other hydrographic factors are relatively constant, and the area of greatest temperature change (Point Conception; see Section IIIB) coincides with the largest shift in tooth length and thickness (Fig. 26).  A similar change in  tooth length for other species of Ulva has not been reported by other authors. Rhyne (personal communication) grew isolates of U. rigida from the northwest Atlantic on a temperature gradient table, but did not observe any change with temperature.  A change of blade thickness with temperature has been  reported for other species of Ulva.  Titlyanov, et a l . , (1975) suggested  that a seasonal change in blade thickness of U. fenestrata from three localities in the Sea of Japan was related to seasonal changes in water temperature.  In their studies blade thickness increased with a decrease of  temperature.  They suggested that this was caused by the retardation of c e l l  108 division and increase in c e l l elongation at cold temperatures.  Data present-  ed in Figure 26b for U. taeniata and general observations of U. fenestrata and U. stenophylla suggest an opposite trend in the northeast Pacific. Specimens of U- fenestrata from Alaska and northern British Columbia tended to be thinner than specimens from Oregon and California (data not presented). However, these observations were made primarily of herbarium specimens that lacked complete collection data.  As indicated by Table 8 and Figure 17a,  thickness in U. fenestrata varies with intertidal position and wave exposure. Vinogradova (1974) reported that c e l l dimensions i n surface view for specimens of U. fenestrata from the northwest Pacific increased from north to south and during the summer months. However, she did not mention whether this change was accompanied with a change in thickness.  In U. taeniata the  increase of thickness with an increase in temperature is accompanied with an increase of c e l l height i n transverse section but not in c e l l width (Table 6). Water temperature may also be responsible for the morphological d i f f e r ences between U. californica and U. scagelii.  These species are similar in  c e l l dimensions, pyrenoid number, thallus shape and habitat.  The primary  difference is the blade length and the habit of the thallus.  The gradual  decrease in blade length and the increase of tufted t h a l l i the further south they are collected may be due to the increase in water temperature or, because both species grow in the upper intertidal zone, may be related in part to an increase in a i r temperature.  The tufted habit of specimens from  southern California allows the t h a l l i to retain large quantities of water while exposed to the a i r . Hence, the tufted habit may reduce the rate of dehydration of the thallus while exposed to air.  Other upper intertidal  ulvaceous algae from southern California (U. rigida, Chloropelta caespitosa) also show a tufted habit.  109 2.  Wave Exposure and Intertidal Position  A l l species studied i n the f i e l d showed some variation with intertidal position and wave exposure.  Species of Ulva from Barkley Sound reached a  maximum size when subtidal or attached to floating objects and decreased in size and often i n thickness with an increase in vertical position i n the intertidal zone.  This was particularly true for U. fenestrata. The decrease  in length and thickness may be related to a reduced photosynthetic capacity when exposed to a i r as is reported for U. expansa (Johnson et a l . , 1974) and U. pertusa (Ogata and Matsui, 1965). Another possible hypothesis i s that the plants i n the upper intertidal zone are more frequently shocked into becoming fertile by exposure to air. cells are capable of becoming f e r t i l e .  In U. fenestrata a l l but the rhizoidal After release of swarmers the fer-  t i l e margin erodes away leaving a much smaller blade that continues to grow. This would result i n smaller, thinner blades i n the upper intertidal zone. Though the release of swarmers in Ulva is cyclic and often occurs during periods of spring tides (Smith, 1947), the formation and release of reproductive cells have been shown i n some species to be independent of desiccation (Smith, 1947; Chihara, 1969). Also i n some areas the formation and release of swarmers occurs during neap tides (Sawada, 1972; Sawada and Watanabe, 1974; Okuda, 1975).  In Barkley Sound plants i n the intertidal  zone, subtidal zone and high intertidal tide pools a l l release swarmers at the same time during the month, so that i t is apparent that some factor other than desiccation initiates reproductive c e l l formation. If desiccation is a major factor affecting growth rate, then wave exposure, a i r temperature, tidal amplitude and tidal periodicity should i n fluence the morphology and perhaps the thickness of t h a l l i growing at a given level i n the intertidal zone. In Barkley Sound plants collected at a specific level in the intertidal zone increased i n thickness with an increase of wave  110  exposure (Fig. 16). This difference was less pronounced i n the lower intertidal and subtidal zones (Fig. 17a). Vinogradova (1974) reported.a decrease of blade thickness for U. fenestrata from, areas of increasing wave exposure; however, she did not mention whether the plants were a l l collected at the same vertical position or not. Desiccation may determine the upper limit of Ulva, though other factors such as competition and grazing may also be important (Chapman, 1973).  Townsend and Lawson (1972) showed that with a tide  simulating apparatus the percent time exposed to air, influenced by the frequency of immersion and the salinity of the water, determined the upper limits of Enteromorpha.  In subtropical and tropical areas wave action and  desiccation appear to be important i n establishing algal zones and upper limits (Lawson, 1957).  May et 31,(1970) found that removal of herbivores  from a vertical transect in New South Wales increased the density of Ulva but not the vertical limits, suggesting physical limitations on its distribution. Thalli also changed in shape and appearance with vertical position. This was particularly true in protected coves and inlets.  Plants growing i n  the upper intertidal zone in Grappler Inlet were often heavily epiphytized, irregular in shape, bullate and pale in coloration.  Continuously submerged,  attached plants were lobed, grass green in color and healthy i n appearance. Unattached plants grew into extensive expanded blades up to a meter or more across.  Similar variation was observed by Steffensen (1976a) for a single  species i n an estuary in New Zealand. However, in Grappler Inlet this variation was unrelated to differences in salinity (Fig. 5a,b). 3.  Seasonal Variation  In British Columbia most species showed a maximum abundance during the spring and summer. This was particularly true for U. stenophylla and U. taeniata which a l l but disappeared i n the late f a l l .  Thallus dimensions also  Ill  varied seasonally.  Specimens of U. stenophylla reached a maximum length in  later summer and early f a l l (Fig. 22b), whereas specimens of U. taeniata reached a maximum length during June through August (Figs. 29b, 30b). Winter forms in both of these species were considerably smaller than summer forms and in the instance of U. taeniata lacked distinct linear lacinae. Similar trends were not as easy to observe in U. fenestrata due to the considerable variation i n specimens from different vertical positions, and seasonal patchiness along the transects in Barkley Sound.  In the winter specimens a-  long the transects were sparse and smaller than summer specimens. Titlyanov, et a l . , (1974) also observed a reduction in the size of specimens during the winter months in the northwest Pacific.  In a similar expanded species in  New Zealand Steffensen (1976a) observed rapid growth of specimens in spring and early summer (October through December).  In the late summer t h a l l i  fragmented and broke away from the substrate. 4.  Morphological and Anatomical Characteristics as Taxonomic Criteria  In the northeast Pacific some species can be identified with some confidence on morphological and anatomical characteristics.  These specimens are  more or less linear and vary in a predictable fashion. North of Point Conception U. taeniata can be separated from other linear species by the presence of marginal teeth.  Ulva stenophylla can be confused with U. scagelii,  particularly when immature.  However, these two species differ in pyrenoid  number and thallus shape. Blades of U. stenophylla are almost always lanceolate, tapering towards the apex. The larger specimens of U. scagelii are oblanceolate, tapering towards the base. Kapraun (1970) graphically separated two species of Ulva using the relationship between length and width.  However, because of the large number of  species in the northeast Pacific and the variation encountered in some species  112 this method cannot be used.  Taxonomic characteristics of the expanded  species of Ulva from the northeast Pacific vary significantly according to their habitat, location in the intertidal or subtidal zones, wave exposure and time of year.  At a given site specimens can f i t the species descriptions  of U. expansa, U. fenestrata, U. lactuca, U. lobata and U. conglobata. Special characteristics such as teeth i n U. rigida appear to be valid taxonomic criteria whereas others such as perforations in U. fenestrata are not (Vinogradova, 1974). A l l of the species from the northeast Pacific vary greatly in c e l l dimensions and blade thickness (Table 6).  These characteristics should not  be used alone for identifying species. Pyrenoid number i s relatively consistent for U. californica and U. scagelii.  However, other species with  several pyrenoids in each c e l l show much variation from c e l l to c e l l and plant to plant. In U. fenestrata pyrenoid number changed with a change i n intertidal position (Fig. 17b). To summarize, morphological characteristics can be used to identify the less variable species such as U. californica (U. scagelii), U. stenophylla, U. taeniata and Chloropelta caespitosa. Expanded species, except for U. rigida, cannot be separated on morphology. Anatomical characteristics are extremely variable and must be used with caution.  113 IV. A.  GROWTH, DEVELOPMENT AND LIFE HISTORIES CULTURE METHODS 1.  Media and Apparatus  Several different culture media were tried including an a r t i f i c i a l seawater mix (Utility Seven-seas Marine Mix, U t i l i t y Chemical Company, 145 Pell St., Paterson, New Jersey), an Erdschreiber seawater enrichment medium (Fjeld, 1970), Suto's enrichment medium (Chihara, 1968) and a modified Provasoli's seawater enrichment medium (Provasoli, 1958).  The best growth  occurred in a modification of the last medium (Table 9) and was used for a l l reported studies.  In a l l culture experiments seawater was taken from the  Bamfield Marine Station seawater system.  This water i s pumped from the  Bamfield Inlet at a depth of approximately 25 meters below the surface and has a salinity of 30-33%.. Seawater was either f i l t e r - s t e r i l i z e d using 0.45 um membrane f i l t e r s or steamed for 1 hour and then filtered.  In some instances  germanium dioxide was added to the culture medium with a final concentration of 0.5 mg/1 to control diatom contamination (Lewin, 1966).  Although cultures  were kept unialgal, no attempt was made to make them axenic.  Different s a l i -  nity media were made by diluting steam and f i l t e r - s t e r i l i z e d seawater with glass d i s t i l l e d water and then adding the stock enrichment solution.  For  salinities above 32%., seawater was boiled to concentrate the salts, filtered and then diluted with d i s t i l l e d water to the appropriate salinities. For most of the studies four large walk-in environment chambers set at 7 , 10 , 15 , and 20 were used. w  For short term experiments a front open-  ing Per cival (Percival Manufacturing Corp., Box 249, Boone, Iowa, U.S.A.) or less dependable Psycrotherm incubators (New Brunswick Scientific Co., New Brunswick, N.J., U.S.A.) were used. A l l three types of chambers were illuminated with Sylvania F48T12 cool white 40 W fluorescent tubes". To produce  Table 9. Seawater enrichment culture medium. Solution A  g/400 ml  NaN0  5.0  3  Na HP0 2  1.0  4  Solution B  mg/100 ml  vitamin B12 thiamine  1.0 50.0  biotin  0.5  Solution C  g/1000 ml  H B0 3  1.0  3  FeCl .6H 0  0.05  MnCl .4H 0  0.16  ZnS0 .7H 0  0.08  CoS0 -7H 0  0.0048  Na EDTA  1.0  3  2  4  4  2  2  2  2  0  Stock Solution:  320 ml soln. A, 8 ml soln. B, 200 ml soln. C and  d i s t i l l e d water to 1000 ml total volume.  Filtered  sterilized.  Culture Medium: 20 ml of stock solution to 1 l i t e r of sterilized seawater.  115 a temperature gradient an aluminium gradient table modified from the design used by Edwards and van Baalen (1970) was constructed (Fig. 32a).  One end  of the plate was cooled by placing the entire apparatus i n the 7° C chamber and pumping cold water from a 20 gallon holding tank through a copper pipe soldered to the bottom side at one end of the plate.  The other end was  heated with a 10", 60 watt strip heater controlled by a rheostat.  For most  experiments the gradient table was placed on top of a shaker table to reduce temperature stratification i n the medium. For the culture of large t h a l l i a seawater flow table was constructed (Fig. 32b). fishing line.  Thalli were tied to a tilted plexiglass table with monofilament Seawater from a holding tank flowed by gravity onto the table  through pores i n a plastic pipe at the top end of the table.  The table was  always used in conjunction with the open seawater system at the Bamfield Marine Station, though i t could easily be modified to be used with a closed system.  Clogging of the pores by diatoms was prevented by placing a few  crystals of Ge02 in the header tank. 2.  Establishment and Examination of Cultures  Thalli collected in the field were wrapped i n damp paper towels and placed in plastic bags or polypropylene jars i n a refrigerator or cooler (2-10° C). Thalli stored i n this manner remained viable for up to a week or more and usually released swarmers within 1 hour to 5 days after placing them in fresh seawater, and exposing them to light. Many attempts were made at controlling the time of release of swarmers of both field-collected and cultured plants.  Desiccation, aeration, frag-  mentation, antibiotic solutions, vitamin solutions (Thaidens and Zeuthens, 1967), fresh enrichment medium and changes of temperature, photoperiod and light intensity were a l l used in attempts to "shock" the t h a l l i into pro-  116  Figure 32.  a. Temperature gradient table. C = copper cooling pipe; H = 60 watt s t r i p heater; R = rheostat; F = fuse, b. Flow table for c u l t u r i n g large specimens. T = holding tank; P = p l a s t i c pipe.  117  118 ducing reproductive cells.  The most dependable method was similar to that  used by Nordby and Hoxmark (1972) and involved a change of medium, temperature, photoperiod and illumination. Small t h a l l i or pieces of t h a l l i grown in culture at 7°, 10°, or 15° C or f i e l d material stored i n dishpans at 10° C under a photoperiod of 12:12 LD and an illumination of 550-3250 HK were rinsed and placed in fresh medium i n a "sporulating chamber" set at 18° C with a 17:7 LD photoperiod and an illumination of 4000 to 6500 £x. Most t h a l l i released within 3 to 5 days at the start of the light period. Thalli that prematurely developed gametangia were kept from releasing gametes for 1 to 2 days by placing them i n the dark at 7° C.  Transfer of these  t h a l l i into the light and fresh culture medium brought about spontaneous release.  Using this method the release of gametes from several different  plants could be synchronized. To establish uniform cultures several drops of swarmers, concentrated by their phototactic response to laterally oriented light, were placed i n a 250 ml beaker stirred by an electromagnetic  stirrer.  One or 2 ml allotments  were transferred into 50 ml petri dishes, and the swarmers were allowed to settle on coverslips i n a dark box. After 24 hours the coverslips were rinsed and placed i n fresh petri dishes and medium. To observe sexual fusion gametes from different plants were placed i n a drop of seawater on a microscope slide oriented laterally to a high intensity light.  Gametes are  positively phototactic and collect on the side toward the light, whereas quadriflagellated zygotes are negatively phototactic and collect on the side away from the light.  If the slide i s mounted on a compound microscope  gametes and zygotes can be easily observed and picked up with a micropipette. Cultures from zygotes were established either i n this manner or by using a mating apparatus similar to that of Nordby (1976). For development and l i f e history studies germlings were grown i n petri  119 dishes until they were 1-2 mm high and then transferred to 250 ml jars. Culture medium was renewed every 1 to 2 weeks for actively growing cultures and every month for cultures in storage at low temperatures and low light intensities.  To determine optimal culture conditions and possible effects  of physical parameters on development and morphology, isolates were grown under a variety of culture conditions.  Most species were grown at three  different temperatures (7°, 10°, 15° C), four different salinities, 5, 15, 25, 35%») or seven different salinities (5, 10, 15, 20, 25, 30, 35%„), and three different illuminations (ca. 550, 1600 and 3250 &x) under a 12:12 photoperiod.  LD  In addition several species were grown on the temperature  gradient table under seven or eight different temperatures (i.e. 9°, 11°, 12°, 14°, 16°, 18°, 20°, ± 1° C).  Culture conditions (temperature and  salinity) were chosen to reflect the range of conditions found in the field (see Section IIIB). Cultures were examined weekly and the germlings photographed and/or measured using an ocular micrometer and a 50x water immersible objective lens or by temporarily mounting the coverslips on sterile slides.  In i n -  stances where the number of cultures in an experiment made i t impossible to examine them a l l in one day, coverslips were mounted in 30% clear corn syrup dissolved in 5% Formalin.  Such preparations, i f checked occasionally to  prevent the formation of air bubbles or i f sealed around the outer edge, are good for several months when unstained and much longer when stained.  In one  experiment 1 cm disks were cut from t h a l l i collected in the f i e l d , weighed and placed in agitated jars under different temperatures and salinities. Rate of growth was measured by changes in diameter, and wet and dry weights of the disks. rate.  Unfortunately the disks tended to become f e r t i l e and degene-  In a l l other studies the rate of growth of germlings was determined  by c e l l number or change in germling length.  120 Throughout this section isolates are identified by collection numbers beginning with the letter (U). Collection numbers represent one or more specimens collected at the same time from a given population (Tables 11-14). B.  LIFE HISTORIES, REPRODUCTIVE DETAILS AND DEVELOPMENTAL PATTERNS 1.  Ulva  A l l species of Ulva from the northeast Pacific studied in culture demonstrated l i f e histories typical of the genus (Foyn, 1929; Bliding, 1968). For each species three types of morphologically similar t h a l l i were encountered.  One type of thallus produced pear-shaped quadriflagellated zoospores  that on release were usually positively phototactic but within a short period of time became negatively phototactic.  However, in one instance quadri-  flagellated swarmers remained positively phototactic (U. scagelii, no. U315). Zoospores generally settled shortly after coming in contact with a solid substrate, dropping or absorbing their flagella and rounding up.  The other two  types of t h a l l i produced biflagellated swarmers that could act either as gametes or spores when compatible gametes of the opposite mating strain were not present. Gametes of opposite mating strains were anisogamous except in U. taeniata where they were isogamous, and were produced by different t h a l l i (unisexual).  The female gametes were larger both i n length and width, and  darker in color than the male gametes. Both types of gametes were positively phototactic and remained motile i n the absence of a compatible mating strain for several hours or longer i f placed i n the dark.  Compatible gametes of  opposite mating strains formed clumps of a few to 100 or more when mixed together.  Fusion was lateral and the resulting quadriflagellated zygotes be-  came negatively phototactic, quickly dropping or absorbing their flagella and rounding up after coming in contact with a solid substrate. In culture zoospores always germinated into gametophytes capable of  121 producing female or male gametes.  Zygotes germinated into sporophytes.  Gametes that germinated parthenogenetically usually produced gametophytes of the same mating strain; however, female and male gametes occasionally produced t h a l l i that released quadriflagellated zoospores. Occasionally t h a l l i released swarmers i n the laboratory that had 6, 8, 10 or more flagella.  These swarmers were generally irregular i n shape,  had more than one eyespot and were considered to be prematurely released swarmers that had not completely separated from one another (Fig. 36f). Release of zoospores and gametes was preceded by a change in color of the fertile areas of the t h a l l i .  In sporophytes and female gametophytes the  f e r t i l e areas were a dark olive green.  In male gametophytes of most species  the fertile area was a pale yellowish or brownish green.  In U. taeniata the  color of fertile areas in both mating strains was the same. In a l l species swarmers escaped from sporangia and gametangia through papillae in the outer wall with a circular or e l l i p t i c a l pore at the apex. Morphogenesis in Ulva from the northeast Pacific followed a complex series of events that could be divided into four stages: 1) germination of reproductive cells; 2) differentiation into an upright filament and a prostrate basal system; 3) development of the upright system into a monostromatic tubular germling; 4) collapse of the tubular germling to form a distromatic blade. The general patterns of development observed are discussed below. Under the microscope flagellated reproductive cells went through rapid spinning movements, always i n a counter-clockwise direction, before attaching.  Settled zoospores, zygotes and parthenogenetic gametes quickly rounded  up, dropped or absorbed their flagella, and secreted a c e l l wall. remained visible for a short period after settling.  Eyespots  In most species of Ulva  settled reproductive cells germinated directly by dividing into two similar  122  Figure 33.  Different early developmental patterns i n Ulva. a . Germination by a germination tube and development of the basal system p r i o r to the upright system ( i . e . U. c a l i f o m i c a , U. s c a g e l i i ) . b. Germination by a germination tube and development of the upright system p r i o r to the basal system ( i . e . U. c a l i f o m i c a , U. scagelii). c . Direct germination and development of the upright system p r i o r to the basal system ( i . e . U. fenestrata, U. stenophylla, U. taeniata). g = germination tube; p = pyrenoid.  123  50 um  124 cells, a basal i n i t i a l and an upright i n i t i a l (Fig. 33c).  When a lateral  light source was used the f i r s t division was perpendicular to the direction 1  of the light with the basal i n i t i a l away from i t .  In U. californica and U.  scagelii reproductive cells either germinated directly or germinated i n directly by means of a germination tube (Fig. 33,34).  In the latter type of  germination the protoplast migrated to the distal end of a long thin-walled protuberance.  The formation of a transverse wall cut off the distal end of  the tube with the protoplast from the empty spore or zygote wall and proximal tube.  This secondary c e l l then divided as before into an upright i n i t i a l  and one or more basal i n i t i a l s , usually with the basal i n i t i a l s distal to the germination tube (Fig. 33a). The empty spore or zygote wall and proximal tube eventually disintegrated over a period of about a week. The upright i n i t i a l s generally divided before the basal i n i t i a l s i n a transverse plane, initiating the development of uniseriate filaments attached by single basal i n i t i a l s .  The basal i n i t i a l s either remained short and round,  or elongated into primary rhizoidal cells before dividing. Longitudinal and transverse divisions of the basal i n i t i a l s and resulting progeny cells followed by c e l l elongation eventually gave rise to multicellular rhizoidal attachment disks.  Under some culture conditions the basal i n i t i a l s of U.  californica and U. scagelii developed into extensive prostrate disks before the initiation of upright filaments (Fig. 33a), The upright uniseriate filaments continued to grow by transverse d i v i sions until lengths were reached that were specific to each species but i n fluenced by culture conditions.  At this point longitudinal divisions occur-  red perpendicular to the surface of each filament to produce multiseriate germlings, though i n some species a single apical c e l l was retained until later on i n the development. Further longitudinal divisions always at right In this thesis a perpendicular, longitudinal or transverse division refers to the orientation of the new c e l l wall.  1  125 angles to the surface resulted in rod-shaped or lanceolate germlings.  In  transverse section cells were arranged i n a ring around a central lumen f i l l ed with an amorphous matrix (Fig. 50c).  As the diameter of the ring of cells  increased the matrix separated except at the base to produce monostromatic saccate germlings (Fig. 50c).  In the lower part of the germling the cells  produced rhizoidal extensions from their inner walls that grew downward and became part of the basal attaching disk. When the upright germlings reached lengths of a few mm to a cm or more, the lumens of the hollow upright portions collapsed with the monostromatic c e l l layers fusing with one another to form distromatic blades (Fig. 50c). Further growth of the blade resulted from c e l l divisions perpendicular to the blade surface (Fig. 50a).  In the species examined divisions i n a plane  parallel to the surface of the blade only occurred during the formation of marginal teeth (Fig. 50b).  Cells in one c e l l layer never divided parallel  to the surface to add cells to the other layer.  Under some culture conditions  the collapse of the hollow germlings was incomplete or absent resulting in hollow Enteromorpha-1ike  plants.  Reproductive and developmental details for species studied i n culture are presented below and i n Table 10. a.  Ulva califomica, Ulva scagelii  Isolates from British Columbia, Washington and California of these two species and intermediate forms released quadriflagellated zoospores and b i flagellated gametes (Table 11; Fig. 34a-c).  Zoospores developed into uni-  sexual gametophytes that eventually released gametes. Female and male gametes were both capable of germinating parthenogenetically into either the same gametophyte strain from which the gametes were released or into sporophytes. Zygotes developed into mature t h a l l i in culture, but the release of swarmers  Table 10. Reproductive and developmental details observed in isolates of Ulva and Chloropelta caespitosa. ileal i f ornica spores/sporangium Spore dimensions length/width (um) gametes/ gametangium  1  4-8  U. fenestrata 8-16  8-12.5/  7-15/  4-6.5  4-7  >16  U. stenophylla  >16  8 11-15/ 4T7.5  8-32  Chi oropelta caespitosa  taeniata 4-8  8-16  8-12/  7-12 long  4.7 8-16  gamete dimensions length/width (um) o_ gametes <? gametes  5-8/ 3-4.5 4-7/ 2-3.5  6-10/ 3-5 4-7.4/ 2-4  9.5-12 long 5-7 long  3-8(11)  10-30  0.1-1.5  5-20  3.5-11/ 2-6.5  2  germination tube no. of cells i n filament when f i r s t longitudinal division length of germling when apical c e l l is lost (mm) other characteristics  9-16 (occ. more)  0.5-1.0  conspicuous basal develop.  n-ris includes isolates from both B.C. and California Isogamous gametes  lr 2  7-15  5-25  1.0-10  marginal dentation  see Section IVB-2  127 from these was not observed. I n these two species a l l but the c e l l s near the base were capable of r e l e a s i n g reproductive c e l l s .  Each sporangium released 4~8 zoospores,  8-12.5 um long and 4-6.5 um wide ( F i g . 34a,b). more gametes.  Each gametangium h e l d 16 or  The gametes were d i s t i n c t l y anisogamous w i t h the female  gametes 5-8 um long and 3 4.5 um wide and the male gametes 4-7 um long and -  2-3.5 urn wide ( F i g . -34c).  Reproductive  c e l l s from t h a l l i c o l l e c t e d from  B r i t i s h Columbia were i n d i s t i n g u i s h a b l e from those c o l l e c t e d i n southern California. Zoospores and zygotes u s u a l l y germinated a few hours a f t e r s e t t l i n g by means of a germination tube ( F i g . 34d,c). nate, often taking several days.  Gametes were much slower to germi-  Parthenogenetic germination of gametes was  u s u a l l y d i r e c t , without a germination  tube.  E a r l y development i n these two species v a r i e d w i t h the d i f f e r e n t c u l t u r e conditions used (see Section I V C - l a ) .  I n c u l t u r e a t r e l a t i v e l y high tempera-  tures an extensive p r o s t r a t e basal system developed before the upright f i l a ment ( F i g . 42). I n t h i s type of development the secondary c e l l a t the d i s t a l end of the germination tube d i v i d e d i n t o a proximal upright i n i t i a l and a d i s t a l basal i n i t i a l or i n i t i a l s ( F i g . 33). By a s e r i e s of mostly transverse d i v i s i o n s and the formation of l a t e r a l r h i z o i d a l branches that were o f t e n l a t e r cut o f f by c e l l d i v i s i o n s , the basal i n i t i a l s developed i n t o a filamentous p r o s t r a t e system ( F i g . 34f,h).  Eventually the upright i n i t i a l d i v i d e d  to i n i t i a t e the formation of the upright system.  A t lower temperatures the  i n i t i a t i o n of the upright system preceded the development of a basal system that was much l e s s extensive ( F i g . 42). I n these species the upright u n i s e r i a t e filament was formed by d i f f u s e transverse d i v i s i o n s as was i n d i c a t e d by the presence of the germination tube at varying p o s i t i o n s along the filament ( F i g . 3 4 i ) . The f i r s t l o n g i t u d i n a l  128 Table 11  Coll. No. U315  U334 U335.5  Isolates of Ulva californica and Ulva scagelii studied in culture.  Collection Location Brockton Point, Vancouver, British Columbia n II  Date  Phase of Field Material  Cultures Started From  S, G  K  Go*  o*  l-VII-77  S, Go.  ^, 9  24-XI-76  3-VI-77  U326  Kitsilano Beach, Vancouver, British Columbia  23-IV-77  Go, Go*  9,  U301  Departure Bay, Nanaimo, British Columbia  17-VI-76  S  If  U308  Botany Beach, Port Renfrew, British Columbia  ll-VII-76  S, G  K  134  Cattle Point, San Juan Island, Washington  19-X-72  S. G.  W  U336  West side of Whidbey Island, Washington  23-VII-77  S. G.  U266.5  San Gregorio Beach, California  31-XII-75  S. G.  U303  Point Joe, California  ll-VII-76  S, G  U290  Wood's Cove, Laguna Beach, California  26-V-76  S. G.  U292  La Jolla Cove, La J o l l a , California  27-V-76  K  ? ,  cf  cf,  c/  9,  cf,  f  9,  cf,  c?  W> 9 ?  S = sporophyte phase; G = gametophyte phase; 0^= zoospore $ = female gamete; o" = male gamete; o* = zygote.  129  Figure 34.  Reproduction and development of Ulva californica and U. scagelii. a. Transverse section through marginal sporangia (scaTe bar = 10 um). Note escape papillae, b. Zoospores, c. Fusing anisogametes. b. Scale bar = 10 um. e. Same scale as (b). d,e. Formation of germination tubes (isolates from B.C.; scale bar = 10 um). f. Development of basal system (U315). g. Development of the upright system prior to the basal system at 7° C (isolate from California (U266.5)). h. Development of the basal system at 10° C (U266.5). i-Jl. Development of the upright germling. m. Incomplete fusion of the two c e l l layers, f - i . Scale bar = 20 um. j . Same scale as ( i ) . k-m. Scale bar = 50 um.  131 division usually occurred toward the base of the filament when i t was 9-16 . or more cells long (Fig. 34j) and quickly spread along the filament.  A single  apical c e l l was retained until the germlings reached a length of between 0.5 and 1.0 mm.  The germlings quickly passed through the multiseriate stage to  form flattened strap-like blades (Fig. 34&) that were distromatic in transverse section (Fig. 34m).  In culture the germlings grew into long, spirally-  twisted, linear blades up to 15 cm long and only a few mm wide (Fig. 9c). Blades often proliferated from the cells of the basal system, particularly under relatively high temperatures (Fig.  44).  b. Ulva fasciata During this study no living specimens of Ulva fasciata were encountered in the northeast Pacific.  However, in order to compare the development of  this species to other linear species from the northeast Pacific (U. stenophyl l a , U. taeniata) specimens from Waimea Beach, Hawaii (21°38.8'N, 159°04.1'W), collected by Dr. P. A. Lebednik, were studied in culture. Specimens from Hawaii released biflagellated swarmers from cells along the margins of the narrow lacinae. The swarmers were positively phototactic and ranged from 6 9 um long and 3~4 um wide. Though several plants released _  swarmers, no differences in size could be discerned between the swarmers from different plants and no sexual fusion occurred. In addition to biflagellated gametes some plants demonstrated an unusual form of reproduction and a vegetative stage unlike the foliose thallus typical of Ulva.  In these plants marginal cells rounded up and were released by  erosion of the margin.  Each released c e l l was surrounded by a thick layer  of wall matrix material (Fig. 35a).  By divisions within the matrix a free  floating globose stage with a monostromatic c e l l layer surrounding a central lumen formed (Fig. 35b-f).  These were irregular in shape, though often  132  Figure 35.  Reproduction and development of Ulva fasciata from Hawaii. a. Release of nonmotile cells from thallus margin (aplanospores). a-f. Formation of globose stage, g. Release of biflagellated swarmers from globose stage. h , i . Development of normal t h a l l i from biflagellated swarmers. a. Scale bar = 50 um. b-d. Same scale as (a). e,g,h. Scale bar = 100 um. f i . Scale bar =1 mm. }  133  134 angular with sharply pointed corners.  Over a period of about a month the  globose stage grew to a size of a few mm, gametangia (Fig. 35g).  and then a l l of the cells formed  Gametes were released that were similar in appearance  and size to those released .by the foliose stage.  These gametes developed  into biflagellated swarmers, germinated directly and followed the "Ulva lactuca-type" pattern of development (Chihara, 1968) in which the upright filament developed before the basal system (Fig. 33c). was typical for the genus.  Later development  Cultured blades were similar in morphology to  the t h a l l i collected in nature and reached lengths of several cm (Fig. 35h,i). Germlings did not develop marginal dentation in culture. c.  Ulva fenestrata  Isolates tentatively identified as U. fenestrata from British Columbia, Washington and California released quadriflagellated zoospores and anisogamous biflagellated gametes (Table 12).  In culture zoospores, zygotes, female  gametes and male gametes germinated and grew into foliose blades similar to specimens collected in the field (Fig. 36,37). However, these blades always lacked perforations.  In only a few instances were t h a l l i grown in cultures  observed to release swarmers. One plant (U264), grown from a gamete, released both quadriflagellated and biflagellated swarmers. Swarmers were usually produced along the margins of the t h a l l i , though at times a l l but the basal rhizoidal cells formed sporangia or gametangia. Each sporangium released 8~16 zoospores that were 7-15 um long and 4 7 -  wide (Fig. 36d).  um  Each gametangium held 16 or more gametes. Female gametes  were 6-10 um long and 3~5 um wide; male gametes were 4~7 um long and 2-4 um wide (Fig. 36e). Zoospores and zygotes settled shortly after inoculation into culture dishes, but motile gametes were occasionally observed 2-3 days later.  Upon  135 Table 12. Coll. No. U139B  Isolates of Ulva fenestrata and related forms studied i n culture. Collection Location Brockton Point Vancouver, B.C.  Date 3-XI-74  U140B  3-XI-74  U316  24-XI-76  Cultures Started From tf  U83  Ross Islets Barkley Sound, B.C.  1-VIII-73  U141  S.E. side of Diani I. Barkley Sound, B.C.  14-XI-74  t  14-XI-74  t  29-111-75  cT  U142 U168  Grappler Inlet, Barkley Sound, B.C.  2-XII-75  U266 U64  Bamfield Inlet, Barkley Sound, B.C.  29-VI-73  f  U79  28-VII-73  U82  l-VIII-73  U86  16-VIII-73  t f  U147  26-1-75  ?, <?, f( ^ w i t h U146)  U149  26-1-75  9>  U239  26-VI-75  If  U267  15- 11-76  f  U19  Aguilar Point Barkley Sound, B.C.  25-V-75  U60  27-VI-73  U63  29-VI-73  U146  S. end of Scott's Cove, Barkley Sound, B.C.  U169 U85 U165  Brady's Beach, Barkley Sound, B.C.  <?, f  25-1-75  cf ( o* with U147)  28-111-75  a* ( cf with U165)  10-VIII-73 28-111-75  %  °, & ( of with U169 & U171)  136 Table 12.  Coll. No.  Continued  C o l l e c t i o n Location  Date  Cultures Started From  U323  Cable Beach, Barkley Sound, B.C.  2-IV-77  0*, 9,  U171  Sooke Harbor, S. end of Vancouver I., B.C.  21-111-75  K  U337  N. side of Smith I., W. side of Whidbey I., Washington  23-VII-77  1£ o, cf, of  U194  Moss Landing, C a l i f .  27-IV-76  U264  Pebble Beach, Carmel, C a l i f o r n i a  7-XI-75  $, cf  U313  Pescadero Point, Carmel, C a l i f o r n i a  12-VII-76  W  U307  Mission Point, Carmel, C a l i f o r n i a  13-VII-76  cT, of  o, cf, cf ( cfwith U165 & U169) 1  %  9  zoospore; K = gamete; 9 = female gamete; cf = male gamete; <j? = zygote.  137  Figure 36.  Reproduction and development of Ulva fenestrata and related species. a,b. Surface and sectional views of sporangia (scale bar = 10 um). c. Transverse section through marginal gametangia (scale bar = 20 um). d. Zoospores, e. Fusing anisogametes. d. Scale bar = 5 um. e. Same scale as (d). f. Incompletely separated gametes (scale bar = 10 um). Note escape pores, g-r. Development of upright germling. g-m, p-r. Isolates from B.C. n,o. Isolates from California. g, j,k. Scale bar = 10 um- h , i . Same scale as (g). Z-o. Scale bar = 20 um. p,q. Scale bar = 50 um. r. Scale bar = 500 um.  139  Figure 37.  Culture of Ulva fenestrata. a,b. Transverse sections through a hollow germling (a) and a distromatic germling (scale bar = 50 um). c-f. Field collected plants (c, U316; e, U139) and resulting progeny grown in culture (d,f). Note lack of perforations in cultured t h a l l i . c. Scale bar = 100 mm. e-f. Scale bar = 50 mm.  141 settling swarmers rounded up and secreted a c e l l wall.  Settled zoospores  and zygotes were noticeably smaller than gametes. Zoospores and zygotes usually took 3~7 days to germinate, whereas parthenogenetic  gametes usually  took 7-14 days. During germination sporelings either divided directly into an upright i n i t i a l and a basal i n i t i a l or produced prior to division a short rhizoidal protuberance directed away from the source of light (Fig. 36g-i). The upright i n i t i a l usually divided f i r s t to form an upright uniseriate f i l a ment (Fig. 36j), though in several germlings the basal i n i t i a l divided longitudinally to form a basal pad of two cells previous to divisions in the upright system.  The f i r s t longitudinal divisions in the upright filaments  occurred towards the base when the filaments reached lengths of 3-8 (11) c e l l s . Single apical cells disappeared at lengths of 100 um to 1.5 mm,  and the mul-  tiseriate germlings quickly became cylindrical with rounded apices (Fig. 36q). During the development of the upright systems into uniseriate andpluriseriate filaments, the basal i n i t i a l s usually divided a few times longitudinally to form small disks of 4 or more rounded cells (Fig. 26&).  Further  divisions and formation of short rhizoidal protuberances produced attachment disks much smaller than that of U. californica (Fig. 36p). Collapse of the cylindrical germlings and adhesion of the c e l l layers produced short strap-like blades.  By further growth of the blades, germlings  developed into curved spatulate or ovate t h a l l i (Fig. 36r,37f).  A few t h a l l i  grown i n culture formed tufts similar i n morphology to U. conglobata (Fig. 37d).  No discernable differences were observed between isolates from d i f -  ferent areas.  Figure 37 shows fertile field-collected plants and their  cultured progeny.  142 d.  Ulva stenophylla  Isolates of U. stenophylla from British Columbia released quadriflagellated zoospores and anisogamous gametes (Table 13).  In culture zoospores,  zygotes and female gametes grew into long linear blades up to 22 cm or more in length that closely resembled t h a l l i collected in the f i e l d .  No attempts  were made at growing male gametes i n culture. Plants grown i n culture could not be induced to release swarmers. Swarmers were produced in cells along the margins of mature t h a l l i . Each sporangium usually held 8 zoospores that were 11-15 um long and 4-7 um wide (Fig. 38a).  The number of gametes in each gametangium varied from 8~32.  Female gametes were 9.5-12 um long and male gametes 5-7 um long (Fig. 38b,c). Zoospores and zygotes germinated between 2 and 5 days after settling, whereas female gametes were slightly slower to germinate, taking 5 or more days.  Cell division was preceded by the development of a rhizoidal protuber-  ance on one side of the sporeling. When clumped zoospores were grown under overhead lights, the rhizoidal protuberances were oriented toward the center of the clump.  By a series of transverse divisions the sporelings developed  into uniseriate filaments (Fig. 38f-h).  The basal i n i t i a l s divided longi-  tudinally to produce several rounded attaching cells after the upright f i l a ments reached lengths of 6-40 or more cells (Fig. 38h).  Later these cells  produced rhizoidal protuberances, but rhizoidal attaching disks never became as extensive as in U. califomica. The f i r s t longitudinal divisions i n the upright filaments occurred at the center or toward the base when the filaments reached lengths of 10-30 cells, though usually around 20 (Fig. 38i). The longitudinal divisions resulted i n long, narrow, cylindrical germlings tapering to single apical cells (Fig. 382.). That these apical cells were important i n controlling longitudinal growth was indicated by the tendency of some germlings to fork subdichot-  Table 13. Isolates of Ulva stenophylla studied i n culture Coll. No.  Collection Location  Date  U224  Grappler Inlet, Barkley Sound, B.C.  9-VI-75  U318  Bamfield Inlet, Barkley Sound, B.C.  22-1-77  U52  Scott's Bay, Barkley . Sound, B.C.  19-VI-73  Cultures Started From ?  U57  II  27-VI-73  U58  •i  27-VT-73  U59  ii  27-VI-73  U62  11  28-VI-73  nr  U226  ti  9-VI-75  if  l  U310  Brady's Beach, Barkley Sound, B.C.  27-VTI-76  V  U230  Cable Beach, Barkley Sound, B.C.  10-VT-75  1  W= zoospore;  b = gamete; 7  <j> = female gamete ; 4 = zygote  144  Figure 38.  Reproduction and development of Ulva stenophylla. a. Sporangia. b. Gametangia. c. Fusing anisogametesT d. Incompletely separated gametes. e-S,. Development of the upright germling. k. Abnormal forked germling. m,n. Transverse sections through a hollow (m) and a partially distromatic (n) germling. '. a-c. Scale bar = 10 um. d. Same scale as (c). e,f. Scale bar = 10 um. g. Scale bar = 10 um. h , i . Same scale as (g). j,n. Scale bar = 50 um. k,i. Scale bar = 200 um. m. Scale bar = 50 um.  145  146 omously at the tip (Fig. 38k). Single apical cells were retained until the germlings had reached lengths of 5 mm to 2 cm. In culture germlings remained hollow until they were a few mm to a few cm i n length.  In many the collapse of the cylinder was incomplete resulting  in blades with hollow areas (Fig. 38n). When grown on the flow table (Fig. 32b), t h a l l i grew quickly to lengths of more than 20 cm.  Plants grown i n  jars usually degenerated after reaching lengths of 1-5 cm.  The basal cells  of these t h a l l i often produced new upright filaments. e.  Ulva taeniata  Isolates of Ulva taeniata from British Columbia released quadriflagellated zoospores and isogamous gametes from different t h a l l i (Table 14). Under some culture conditions, zygotes and gametes grew into linear, dentate t h a l l i that closely resembled plants collected i n the f i e l d .  Thalli (U126)  grown from gametes produced gametes. Swarmers were produced i n cells along the margins and at the tips of mature t h a l l i .  Each sporangium held 4 8 zoospores that were 8-12 um long _  and 4-7 um wide (Fig. 39a,b).  Each gametangium held 8~16 gametes (Fig. 39d).  Gametes varied greatly i n size, and, though fusing pairs were often of d i f f e r ent dimensions, gametes from different t h a l l i could not be distinguished (Fig. 39c). Gametes varied from 3.5-11 ym i n length and from 2-6.5 ym i n width. Zoospores and zygotes germinated a few days after settling, whereas gametes germinated 4 or more days after settling.  Rhizoidal protuberances  developed on the side of the sporelings distal to the light source. Several transverse divisions produced upright filaments attached by single rhizoidal basal cells (Fig. 39f,g).  The basal system developed further when the f i l a -  ments were 100 ym or longer by the production of secondary rhizoids from cells  Table 14. Isolate of Ulva taeniata studied i n culture Coll. No.  Collection  Location  Date  U243  Islet west of Helby I., Barkley Sound, B.C.  9-VII-75  U153  Brady's Beach, Barkley Sound, B.C.  22-11-75  U229  10-VT-75  U280  13-V-76  U309  27-VTI-76  U317  22-1-77  U321  2-IV-77  U126  Cable Beach, Barkley Sound, B.C. zoospore ;  K = gamete;  Cultures Started From  13-IX-74  ' = zygote from isogamous gametes,  148  Figure 39.  Reproduction and development of Ulva taeniata. a. Zoospore. b. Marginal sporangia (scale bar = 25 ym). c. Fusing isogametes. d. Marginal gametangia. a,d. Scale bar = 5 ym. c. Same scale as (a), e. Clumping of gametes.from compatible mating strains (scale bar = 100 ym). f-m. Development of upright germling. f. Scale bar = 100 ym. g. Scale bar = 10 ym. h. Same scale as (g). i , j . Scale bar = 50 mm. k. Germling grown i n 10%« culture medium. k,&. Scale bar = 100 ym. m. Scale bar = 200 ym. n,o. Transverse sections through a hollow germling (n, scale bar = 25 ym) and a distromatic germling (o, scale bar = 50 ym).  150  in the lower part of the upright filaments. The f i r s t longitudinal divisions occurred i n the lower half when the filaments reached lengths of 7-15 cells (Fig. 39h,i).  Continued longitudi-  nal divisions produced cylindrical germlings tapering to single apical cells as in U. stenophylla (Fig. 39j,&).  The cylindrical germlings collapsed and  developed into distromatic blades when 1-2 mm in length.  The blades were  attached by colorless unbranched rhizoidal cells, occasionally interrupted by series of small rectangular cells, resembling cells of the blade.  At this  stage under some culture conditions (see Section IVC-ld) scattered cells along the margin divided parallel to the surface to initiate the development • of marginal teeth (Fig. 39m). Most teeth were determinate reaching a maximum size of a few mm.  Other teeth showed indeterminate growth, developing into  lobes or lacinae.  Single apical cells were retained until the germlings  reached lengths of 2 mm to over a cm. Marginal teeth and branches retained single apical cells up to lengths of a few mm.  Thalli grown in jars reached  lengths up to 28 cm. 2.  Chloropelta caespitosa  Isolates of Chloropelta caespitosa, collected at Point Fermin, California, on May 26, 1976 and August 24, 1977, were cultured through several generations. .Each generation was similar in development and morphology to the previous one.  However, due to d i f f i c u l t i e s in controlling the time of re-  lease of swarmers in Chloropelta, a l l of the reproductive details were not clarified.  Mostly quadriflagellated swarmers were observed, though on two  occasions, once from field-collected plants and once from plants grown i n culture, biflagellated swarmers were observed, but i t was not possible to determine whether these came from different plants from those releasing quadriflagellated swarmers.  Sexual fusion between biflagellated or quadriflagel-  lated swarmers was not observed.  151  Figure 40.  Reproduction and development i n Chloropelta caespitosa. a. Escape pores for zoospores. b. Sporangia. c. Quadriflagellated zoospores, b. Scale bar = 10 um. a c. Same scale as (b). d. Clumps of settled zoospores (scale bar = 100 um). e,f. I n i t i a l development of filamentous germling. e. Scale bar = 20 um. f. Same scale as (e). g-k. Development of upright multiseriate germling. g-i,k. Scale bar = 50 um. j . Germling grown at 35 % . Same scale as ( i ) . l,m. Monostromatic saccate germlings (scale bar = 250 ym). n. Proliferation of germlings from basal rhizoids (scale bar = 100 um). o. Dendroid basal system (scale bar = 100 ym). p. Germling grown at 5 %« (scale bar = 25 um). q. Distromatic saccate germling. r. Degeneration of cells at the apex. s. Germling releasing zoospores from apex (scale bar = 250 ym). t u . Campanulate germlings. q r , t . Scale bar = 1 mm. u. Scale bar = 2 mm. 3  0  3  5  152  153  Figure 41.  Development of Chloropelta caespitosa.. a-c. Transverse sections through multiseriate (a) and monostromatic hollow (b,c) germlings (scale bar = 5 um). d. Transverse section through transition zone showing monostromatic and distromatic areas (scale bar = 100 um). e. Transverse section through distromatic germling (scale bar = 100 um). f,g. Transverse section through rhizoidal base (scale bar = 5 um). j-m. Longitudinal sections, j . Distromatic saccate germling with a monostromatic apex (scale bar = 250 um). Arrow indicates transition area. n,o. Outer and inner surfaces of campanulate germling. n. Scale bar = 10 um. h , i , k-m, o. Same scale as (n).  154  mm A J  mm-  155 Zoospores were pear-shaped, 7-12 ym long, with four flagella inserted at the narrow end (Fig. 40c).  Each zoospore contained a single cup-shaped  chloroplast with an orange eyespot.  Eight to sixteen zoospores were produced  in each sporangium along the margins of mature t h a l l i and at the apex of saccate germlings in culture (Fig. 40b,s).  Zoospores escaped from the spor-  angia through papillae with circular or e l l i p t i c a l pores at the apex from 5-9 ym in diameter (Fig. 40a).  Zoospores were at f i r s t positively phototac-  t i c but quickly became negatively phototactic and tended to settle in clumps of a few to many cells (Fig. 40d). Settled spores germinated directly without the formation of germination tubes into a basal attaching c e l l and an apical c e l l .  Transverse divisions  of the apical c e l l and resulting daughter cells gave rise to an upright uniseriate filament that reached lengths of 5-25 cells before the f i r s t longitudinal division occurred (Fig. 40a-h). at f i r s t a primary rhizoidal c e l l .  Elongation of the basal c e l l formed  Later divisions of this c e l l and result-  ing daughter cells, followed by c e l l elongation, gave rise to a loosely organized rhizoidal attaching system.  Longitudinal divisions of the cells  in the upright filament perpendicular to the surface produced a rod-shaped multiseriate germling (Fig. 40i-Jl,50d).  In transverse section the cells of  the multiseriate filament were arranged in a ring, the lumen of which was at f i r s t f i l l e d with an amorphous matrix (Fig. 41a,b). As the diameter of the ring of cells increased the matrix separated in the upper two thirds or more of the germling to produce a monostromatic saccate germling (Figs. 40m,41c). In the lower part the cells produced rhizoidal extensions from their inner walls that grew downward and became part of the attaching system (Fig. 41f,g). In some cultures the attaching system consisted of prostrate multiseriate filaments.  These filaments were strand-like and branched in a dendroid  fashion (Fig. 40o).  The cells of narrow branches were elongate, but the cells  156  in the thicker strands lacked rhizoidal protuberances and resembled the cells of the upright system.  New germlings often proliferated from these basal  filaments producing clumps of germlings. When the germlings were one to a few mm t a l l , each c e l l of the monostromatic c e l l layer divided once longitudinally i n a plane parallel to the surface of the germling to form a distromatic c e l l layer around the enclosed lumen (Fig. 41d,e,i,j,&,m).  The f i r s t of these divisions occurred above the  solid rhizoidal base and proceeded toward the apex.  In some germlings the  apical end remained monostromatic, but degeneration of the apex resulted i n a completely distromatic germling (Fig. 41r). The distromatic saccate germlings eventually ruptured at the apex by one of two methods.  In the f i r s t the cells of the monostromatic or distro-  matic apex degenerated and caused the apex to r i p open (Fig. 40r).  In the  second method cells in an irregular disk at the apex developed into sporangia (Fig. 40s).  A clear degenerative area developed between the f e r t i l e  disk and surrounding vegetative cells and eventually, after release of the swarmers, caused the fertile disk to f a l l out of the germling.  The opening  was at f i r s t tattered and irregular, but continued growth of the distromatic blade resulted i n a campanulate thallus 5-15 mm t a l l (Fig. 40t,u). At this stage a l l divisions i n the blade were perpendicular to the surface so that each of the two layers of cells was independent of the.other, and a distinct line of demarcation developed between c e l l wall material of each layer (Fig. 41i).  Further growth led to a flattened orbicular or oblong blade up to a  few centimeters in diameter attached in the center by a cone-shaped rhizoidal base.  157 C.  RESPONSES TO VARIATION IN TEMPERATURE AND SALINITY  To study the effects of temperature and salinity on development and morphology, isolates of Ulva and Chloropelta were grown under a variety of culture conditions.  These culture conditions are listed on Table 15. Re-  sults of the studies are given below. 1.  Ulva californica, Ulva scagelii  Isolates from British Columbia (U315, U335.5, U301, U308) and southern California (U290) responded i n a similar fashion to different salinities and temperatures, though some variation was observed between isolates.  Only  slight changes in germling morphology occurred between 10%„ and 35% . At 0  5%  germlings were irregular in morphology and slow i n growth.  The prostrate  basal system increased slightly i n diameter with an increase of salinity along with the proportion of cells i n the upright system producing rhizoidal protuberances. and  35%c  L i t t l e difference was observed i n growth rate between 10%  o  (Fig. 46a).  Ulva californica and U. scagelii demonstrated a marked amount of variation in development when grown at different temperatures. When grown at 10° or less the upright filament developed before the basal system (Fig. 42). The extent of development of the basal system increased rapidly with an i n crease of temperature (Figs. 42-45).  Figure 45 shows that the increase i n  the basal system was not due simply to an increase i n the growth rate.  Maxi-  mum growth of the upright system occurred at 15° C i n cultures of U335.5 and at 15° and 17° i n U290 (Figs. 44,45).  The degree of proliferation of new  blades from the basal system also increased at higher temperatures (Figs. 43,44).  Table 15. Conditions under which isolates of Ulva and Chlorpelta caespitosa were cultured to study the effects of temperature and salinity on development and morphology. Isolates U. californica  z  U301, U308, U315 U290 U290, U335.5  U. fenestrata  U. taeniata  1  t  Y t  U267  t  U316  9.  U323, U337 U. stenophylla  Cultures Started From  r  U310  Temperatures (C)  Salinities (S %, )  10°,15°  5,10,15,20,25,30,35  10°,15°  5,15,25,35  9.5°,11°,13°,15°,17° 19°  30  10°  5,10,15,20,25,30,35  10° 15°  5,10,15,20,25,30,35  3  9°, 11°,12°,14°,16° 18°,20°  30 5,10,15,20,25,30,35  •10°,15°  U318  7°,10°,12°,14°,16° 20°,22°  U280  10°  5,10,15,20,25,30,35  9°,11°,12°,14°,16° 18°,20°  30  9°,11 12 14 16° 18°,20°,22°  30  7°,10°,12°,14°,16° 18°', 20° ,22°  30  U317  t  U321  1  U280  0  0  5  0  5  5  30  Table 15. Continued.  Isolates Chloropelta  U288  Cultures Started From  Temperatures (C)  t  10°,15°  Salinities (S %„) 5,10,15.20,25.30,35  caespitosa 1  ( f = zoospores; $ = gametes; £ = female gametes;  2  This includes isolates from British Columbia identified as JJ. scagelii (U301, U308, U315, U335.5) and isolates from California more typical of U. californica (U290).  /  = zygotes.  160  Figure 42. Development of Ulva scagelii (U335.5) at different temperatures over a 3 week period after inoculation. At low temperatures (9.5°, 11° C) development of the upright filament preceded development of the basal system. At higher temperatures (13°, 15°, 17 , 19° C) basal development preceded initiation of upright filament. One Week: 9.5°, scale bar = 50 um; 11°-19° scale bar (11°) = 50 um. Two Weeks: .9.5°, scale bar = 50 um; 11-13°, scale bar (11°) = 5g um; 15-19°, scale bar =• 100 um. Three Weeks: 9.5 , scale bar = 50 um; 11°, scale bar = 100 um; 13-19°, scale bar (13°) = 200 um.  161  1 wk  9.5°  9 •  2wk •  3 wk  I  /  11°  2 1  13°  -I 0  (  is-  1  J  162  Figure 43. Morphology of 4-week-old germlings of Ulva scagelii (U335.5) grown at different temperatures. Note increasing size of basal disc with an increase of temperature.  164  Figure 44. Morphology of 8 week-old germlings of Ulva californica (U290) grown at different temperatures. Note the proliferation of new germlings from the base at higher temperatures. Part of the rhizoidal basal discs were lost when the germlings were removed from coverslips and mounted for examination.  166  Figure 45. a. Growth in diameter of basal discs of Ulva scagelii (U335.5) at different temperatures. b. Growth in length of blades of U. scagelii (U335.5) at different temperatures. • . . Each point represents the average of 10-20 measurements.  167  14  21 AGE (DAYS)  28  168 2.  Ulva fenestrata  Germlings grown at low salinities (5, 10% ) tended to be either irrego  ular in shape or relatively short and wide. Otherwise, U. fenestrata showed very l i t t l e variation in morphology when grown at different salinities and temperatures. factors.  However, the rate of growth was affected by both of these  The fastest growth occurred between 20% and 30%„ (Fig. 46b) and o  at 16° and 18° C. 3.  Ulva stenophylla  Development of germlings was normal between 15%. and 35%„.  At 5% few 0  spores germinated and those that did grew into irregular clumps of cells. At 10%* germlings were often forked and had irregular outlines. The maximum rate of growth occurred at 25%o and 30% (Fig. 47). o  After a week of growth at different temperatures, normal development occurred between 10° and 16° with a maximum rate at 12° and 14° C. At 7° C most of the germlings were forked.  Between 18° and 22° C the germlings were  irregular and unhealthy in appearance. 4. Ulva taeniata Development and morphology in U. taeniata were affected by both s a l i nity and temperature in culture. A l l of the germlings died at 5% , and only 0  a few survived at 10% . o  d).  Maximum growth in length occurred at 25% (Fig. 46c,. D  Determinate teeth developed on 3 week old plants grown at 20% , 25%* o  and 30%« with a maximum development at 25% . At 10% and 15%o teeth were 0  o  few and indeterminate, developing into forks or branches. served in 3-week-old plants grown at 35% . D  No teeth were ob-  The length and density of basal  rhizoids increased with an increase of salinity. At different temperatures maximum growth occurred between 14° and 18° C.  169  Figure 46. Growth of Ulva i n culture at different salinities at 10° C.. - U. scagelii (301; 1 week-old germlings). b. U. fenestrata (U267); 1 week-old germlings). c,d. U. taeniata (U280). ' c. Two week-old germlings. _d.. Three week-old germlings. a-c. Relative growth was measured by the number of cells i n the upright filament, d. Relative growth was measured by germling length. Each point represents the mean of 22-83 measurements. Vertical bars represent the standard deviation of the means. a  170  171  Figure 47. Growth of Ulva stenophylla (U310) at different salinities at 10° C (a,b; 2 and .3 weeks) and 15° C (c,d; 2 and 3 weeks). Relative growth was determined by.germling length. Each point represents the mean of 21-40 measurements. .Vertical bars represent the standard deviation of the mean.  172  173  Figure 48. Morphology of 7 week-old germlings of Ulva taeniata (U321) grown at different temperatures. Note the marginal dentation of germlings grown at low temperatures (9 , 11°, 12°, 14° C).  175 At 22° C and above a l l of the germlings died.  The number and length of  teeth and branches increased with a decrease of temperature (Fig. 48). bove 16° C germlings lacked teeth and branches. short round teeth and no branches.  A-  At 16° C germlings had  Below this germlings became progressively-  more dentate and branched (Fig. 48). 5.  Chloropelta caespitosa  Germlings grown i n salinities of 15%, or less became irregularly globose and produced less developed rhizoidal systems than at higher salinities„ (Fig. 40).  None of these germlings developed beyond the monostromatic sac-  cate stage. Germlings grown in salinities of 20%  o  or greater a l l went  through the developmental pattern described for Chloropelta.  In cultures  grown i n salinities greater than 2 0 % r h i z o i d a l cells extended further up the upright germling than in lower salinities (Fig. 40i,j). D.  HYBRIDIZATION EXPERIMENTS Strict intersterility barriers between species of Ulva have been demon-  strated by Foyn (1955), Bliding (1968) and Kapraun (1970).  In their studies  gametes of different species fused but the zygotes failed to develop more than a few cells.  According to Bliding (1963, 1968) delayed fusion or lack  of viable zygotes from fusion can be used to delimit species.  During the  study of northeast Pacific species of Ulva, hybridization experiments were used to confirm conclusions from f i e l d and culture studies.  Figure 49 gives  the results from crossing intraspecific and interspecific gametes. 1.  Ulva califomica, Ulva scagelii  Gametes from t h a l l i collected i n British Columbia and morphologically similar to type specimens of U_. scagelii (U315; see Table 11) fused immediate-  176 ly after mixing with gametes from t h a l l i collected in California (U303) and morphologically similar to type specimens of U. californica (Fig. 6c). This cross resulted in germlings similar to ones grown from zoospores.  Isolates  from California (U266.5, U303) also fused with an isolate from the west coast of Vancouver Island (U308; Fig. 6a) resulting in viable zygotes. 2.  Ulva fenestrata  Thalli from different localities i n British Columbia identified with U. fenestrata successfully crossed and produced viable zygotes (Fig. 49; Table 12),  In some instances these t h a l l i differed morphologically. For example  small lobed plants (U167) crossed with large, orbicular, perforate plants (U169, U171). Gametes of a tufted high intertidal plant from California (U307) resembling U. conglobata did not clump or fuse with gametes of U. fenestrata from British Columbia (U323). 3-  Ulva fenestrata with Ulva californica and Ulva scagelii  Gametes did not clump or fuse i n attempted crosses of U. fenestrata (U316, U323, U335, U337) with U. californica and U. scagelii (U266.5, U303,  U308, U315, U334, U336).  The attempted cross between 'U. conglobata' (U307)  from California and U. californica was also unsuccessful. 4.  Ulva lactuca  Living specimens of U. lactuca from Helgoland (U333) were obtained from Dr. J. W. Markham. Thalli were induced to release female and male gametes, and attempts were made to cross these with gametes of U. californica (U303) and U. fenestrata (U335).' Gametes from U333 and U303 did not clump or fuse. Gametes from U333 and U335 did not clump but a few laterally fused gametes were observed several minutes after the gametes were mixed together.  177  Figure 49. Results of crossing experiments. A plus (+) indicates a positive clumping and fusing response. A minus (-) indicates no mating response. U ca = U. califomica. U sc = . U. scagelii. U .fen = U. fenestrata. U c = U. conglobata. U I = U. lactuca_(from Helgoland). U st = U..stenophylla. U t = U. taeniata. U ca and U sc are distinguished on the basis of geographic location. Isolates of U ca are from California. Isolates of U. sc are from British Columbia. Gametes of U t are isogamous and, therefore, cannot be separated into male and female strains.  6  U ca  Use  U 2 6 6 5 303 308 315 326 334 9 6 ^11303  +  U st  1 4 6 1 4 7 1 4 9 1 6 9 171 3 2 3 3 3 5 3 3 7 3 0 7 3 3 3 5 7  + +  —  —  58  U t 1 2 6 2 8 0 321  —  +-  326 336  -  —  •  +  96  +  147  + +  148  +  165  + +  169  c -  U I  + +  308 «  Uc  U fen  —  316 323  —  335  — • —  —  —  — —  337  S  307  3  333  '  57  =>  58 126  ~  280 321  — —  + + + +  179 The delay i n fusion and small number of fused gametes observed were interpreted as a negative mating response (see Bliding, 1963). E. DISCUSSION 1.  Life Histories and Reproductive Details  Life histories i n Ulva from the northeast Pacific a l l follow the same pattern and can not be used to separate species.  The only deviation observed  in culture was i n U. fasciata from Hawaii in which cells (aplanospores) from the margin of blades developed into minute but multicellular, floating globose t h a l l i .  Growth i n this stage was determinate and cells eventually re-  leased normal-appearing biflagellated swarmers. Foyn (1934) observed a similar stage in a culture of U. lactuca.  However, in his study the globose  stage developed from germlings that broke away from the substrate, and eventually released abnormal swarmers. Bonneau (1978) observed the formation of polymorphic globose t h a l l i from isolated cells in degenerate germlings of U. lactuca. germlings.  These occasionally produced swarmers that developed into normal The ability of the globose t h a l l i of U. fasciata to float with  water currents and produce swarmers suggests that they would be advantageous for the dispersal of the species.  To my knowledge similar stages have not  been observed i n the f i e l d , possibly because of their diminutive size and floating habit.  Unfortunately, U. fasciata from the northeast Pacific (west  coast of North America) has not been studied in culture, and i t i s not known whether specimens from this area exhibit reproduction and development similar to specimens from Hawaii or other areas.  Specimens from Morocco (Cauro, 1958)  and the Gulf of Mexico (Kapraun, 1970) showed an alternation of unisexual gametophytes with sporophytes as i s typical for the genus. These isolates were also anisogamous, a characteristic that can be used to separate U. fasciata from these areas from the morphologically similar U. taeniata. It  180 w i l l be of interest to compare these two species in culture i f living specimens of U. fasciata can be found in the northeast Pacific. The complete l i f e history of Chloropelta caespitosa has not been observed, though the presence of both quadriflagellated and biflagellated swarmers, the absence of a cyst-like stage and evidence for t h a l l i with two different ploidy levels (see Section V) suggest an alternation of isomorphic sporophyte and gametophyte generations similar to that of Ulva. The type and size of reproductive cells have been suggested as possible taxonomic criteria for separating ulvaceous species (van den Hoek, 1964; Bliding, 1964; Kapraun, 1970).  In the northeast Pacific only one species  differs i n the type of reproductive cells.  Ulva taeniata has isogametes,  whereas a l l other species have anisogametes.  The dimensions of swarmers  could not be used to separate species as these varied considerably (Table 10), even from individual t h a l l i . 2>  Developmental Patterns  a.  Ulva  Development and morphogenesis in Ulva has been studied in detail (Yamada and Saito, 1938; Cauro, 1958; Foyn, 1959; Baudrimont, 1961; Ltfvlie, 1964; Yoshida, 1965; Bliding, 1968; Ltfvlie, 1968; Chihara, 1968, 1969; Kapraun, 1970; Rhyne, 1973; Bryhni, 1974).  Though germlings show considerable varia-  tion when grown in axenic culture (Provasoli, 1958, 1961; Kapraun, 1970; Bonneau, 1977), isolates grown i n unialgal nonaxenic culture often produce t h a l l i similar to specimens collected in the field (Bliding, 1968; Chihara, 1968, 1969; Kapraun, 1970).  In several instances development has proven  valuable in describing or separating species (Cauro, 1958; Bliding, 1968; Chihara, 1968, 1969). In the northeast Pacific developmental patterns were useful for sepa-  181 rating species and for understanding how environmental factors such as temperature and salinity modify morphology.. Differences between species were observed in germination of reproductive cells, development of the basal attaching system, and development of the upright germling.  In the latter  length of uniseriate filaments when the f i r s t longitudinal divisions occurred and the persistence of apical cells were important (Table 10).  Ulva steno-  phylla and U. taeniata can be separated from other species on the above c r i teria.  Specimens tentatively assigned to U. califomica and U. scagelii re-  spectively from California and British Columbia demonstrated similar developmental patterns.  Chihara (1968) designated the germination pattern of U.  scagelii as the "Ulva-scagelii-type" to differentiate i t from "Ulva-lactucatype" germination found in most species.  Orbicular, lobed and expanded  specimens, identified as U'.! fenestrata, U. expansa and U. lobata, also showed similar developmental patterns to each other.  Development in this group re-  sembled that reported for U. conglobata (Yamada and Saito, 1938). This lends support to Vinogradova's (1974) placement of U. pertusa as a synonym of U. fenestrata and Hommersand's (1972) suggestion that U. conglobata might be a small form of U. pertusa. In some species temperature modified developmental patterns and morphology of the resulting t h a l l i .  In U. califomica and U. scagelii the diameter  of the basal disk increased with an increase of temperature.  Associated with  this was an increasing proliferation of blades from the basal disk.  The modi-  fication of development of these species can be related to the tufted appearance of U. califomica in southern California and the solitary habit of U. scagelii in British Columbia.  Dentation in U. taeniata was also modified by  temperature in culture. The number and length of teeth decreased with an i n crease of temperature.  This relates well to the reduction in the length of  teeth of plants in the f i e l d the further south that they were collected (see  182 Section IIID-1).  Normally blades develop by diffuse divisions perpendicular  to the blade surface (Bryhni, 1974). Teeth, on the other hand, are initiated by divisions parallel to the margin surface which is equivalent to the blade surface (Fig. 50a,b).  Bryhni (1974) suggested that the orientation of c e l -  lulose f i b r i l s i n the c e l l wall may be important in determining the orientation of division planes.  If this is true then temperature might be expected  to affect wall deposition around cells along the blade margin. Culture studies indicate that U. stenophylla grows normally in a relatively narrow range of temperatures (10-16° C).. This corresponds well with herbarium and field studies.  Though i t has been collected as far south as  Santa Barbara, U. stenophylla is rare south of Monterey. is Vancouver Island.  Its northern limit  The mean coastal surface temperatures i n this area  (Vancouver I. to Monterey) range from 9°-14.5° C (Naval Oceanographic Office, 1969).  In Barkley Sound rapid growth occurred in this species when water  temperatures were between 9° and 16° C (Figs. 5c,d,22b). When temperatures were below 8° C plants were scarce and small.  Unlike U. stenophylla, U.  fenestrata showed a wide tolerance to temperatures in culture. Though growth rate was influenced by culture temperature, germling morphology was not. Culture studies suggest that the distribution of U. fenestrata along the west coast of North America is not limited by temperature.  Biebl (1972) has shown  that U. pertusa i s tolerant of extremely high and low water temperatures. Species of Ulva also differed i n their tolerance to different salinities in culture. Ulva stenophylla and U. taeniata had narrow tolerances, whereas U. californica and U. fenestrata had wide salinity tolerances.  Again these  differences reflect the distribution of the species i n the f i e l d .  Ulva  taeniata and U. stenophylla are restricted to the open coast or bays with high salinities.  U. californica (U. scagelii) and U. fenestrata have been  collected both on the open coast and in brackish inlets along the British  183 Columbia coast.  Kjeldsen and Phinney (1973) reported that U. taeniata grew  at the mouth of Yaquina Bay, Oregon, and that U. lobata, U. rigida, U. fenestrata and U. expansa occurred increasingly further back i n the estuary. I suspect that the last four species represent morphological variations of a single species.  Kapraun (1970) reported a gradation of morphological forms  of Enteromorpha depending on salinity.  Druehl (1967) suggested that i n  estuaries salinity and temperature stratifications affected the upper limits of Ulva and other algae.  Although the studies i n this thesis indicate that  some species are more tolerant than others, caution must be used in applying salinity tolerances in culture to field plants.  Ogata and Matsui (1965)  found that tolerance differed when different culture media were used, and Zavodnik (1975) reported that tolerances differed when spring water was used instead of d i s t i l l e d water to dilute sea water. b.  Chloropelta  Although the i n i t i a l stages of development in Chloropelta resemble that of Ulva and other members of the "natural family", Ulvaceae (Bliding, 1968), the formation of the distromatic blade by divisions parallel to the blade surface is a clear departure from these genera or other ulvaceous algae. When the uniseriate filaments of the Ulvaceae and Chloropelta reach specific lengths influenced by environmental factors, longitudinal divisions perpendicular to the surface of the germling at f i r s t produce multiseriate germlings.  This i s followed by the formation of monostromatic cylindrical  germlings.  Most other members of the Ulvales sensu Bliding (1963, 1968),  with the exception of Percursaria (Kornmann, 1956) and a few species of Monostroma (Kornmann and Sahling, 1962; Tatewaki, 1972), also pass through a hollow stage.  However, in most members of the Monostromataceae the hollow  stage develops from horizontal divisions i n the center of the prostrate disk  184  Figure 50..  a b. Planes of d i v i s i o n along nondentate (a) and dentate (b) margins i n transverse section. Divisions are normally perpendicular to the surface except during the formation of teeth. c. Developmental patterns i n various genera belonging to the Ulvaceae. Transverse sections s t a r t i n g with a u n i seriate filament. . d. Development of Chloropelta i n longitudinal section. }  185  Chlorogejta  186 followed by an upheaval of the upper monostromatic layer of cells.  In Mono-  stroma undulatum Wittrock a uniseriate filament develops directly into a monostromatic blade without passing through a hollow stage (Kornmann and Sahling, 1962). It i s at the hollow stage that Chloropelta departs from the type of development characteristic of the Ulvaceae.  Contrary to what i s stated i n  several books on the algae and lower plants (Fritsch, 1935; Scagel et a l . , 1965; Morris, 1967; Chapman and Chapman, 1973; Bold and Wynne, 1978; Trainor, 1978) divisions never occur in a plane parallel to the surface of the germling i n the Ulvaceae to produce a distromatic blade.  Instead the distromatic  blade of Ulva forms by the collapse of the hollow germling and the adhesion of the c e l l layers (L^vlie; 1964; Fig. 50c). independent.  The two layers, however, remain  In Chloropelta the distromatic blade forms by a single division  of each c e l l in a plane parallel to the surface of the blade (Fig. 50c,d). Subsequent development in Chloropelta closely resembles that of Monostroma fuscum (Dube, 1967). 3.  Hybridization Experiments  Results of hybridization experiments were consistent with studies from other areas (Bliding, 1968; Kapraun, 1970) and helped to test observations made during f i e l d and culture studies.  Isolates typical of U. scagelii from  British Columbia and isolates typical of U. californica from California crossed and produced viable zygotes.  Likewise, lobed and expanded specimens of U.  fenestrata crossed and produced viable zygotes.  These crosses provide support-  ive evidence for the placement of U. scagelii as a synonym of U. californica and U. fasciata f. lobata as a synonym of IJ. fenestrata (see Section VIA). Attempted crosses between species that are morphologically and developmentally distinct failed, indicating the presence of interspecific s t e r i l i t y barriers.  187 V.  CYTOLOGICAL STUDIES Several cytological studies have been reported on for species of Ulva  and other ulvaceous algae, yielding haploid numbers that varied from 8 to 13 (Table 16).  These earlier studies were concerned primarily with confirming  the alternation of a diploid sporophyte with a haploid gametophyte and did not attempt to assess the potential of using chromosome numbers for delimiting species.  Few species of Ulva were studied, and the resulting counts were  often conflicting (Table 16). During this study chromosome counts were made for five species of Ulva from the northeast Pacific and for Chloropelta caespitosa to determine i f chromosome numbers could be used to delimit species. A.  METHODS For chromosome counts t h a l l i were fixed in either 3:1 ethanol: acetic  acid or in Buffaloe's fixative (Buffaloe, 1958) and stained with either acetocarmine (Godward, 1966) or aceto-iron-haematoxylin-chloral hydrate (Wittmann, 1965). The best combination was Buffaloe's fixative with haematoxylin stain. Buffaloe's fixative tended to stain the chloroplast, decreasing the overall contrast, but the fixed material was not as b r i t t l e as i t was in ethanol : acetic acid and demonstrated superior staining qualities. Mostly gametophytes grown in culture from zoospores and parthenogenet i c gametes, or gametophytes collected from the field undergoing gametogenesis were used for this study as the primary purpose was to determine haploid numbers. Thalli were fixed in the f i e l d and in culture over 24 hour periods to determine when cells were most actively dividing.  As reported by several  other investigators (Ramanathan, 1939; Yabu and Tokida, 1960; Linskens and Vennegoor, 1967; Kapraun, 1970; Lc^vlie and Braten, 1970; Sarma and Chaudbury, 1975) the maximum number of vegetative divisions occurred during the dark  188 Table 16.  Chromosome numbers i n the Ulvaceae.  Taxon  Chromosome No.  Reference  Ulva curvata  n = 10-12  Rhyne (1973)  U. fasciata  n = 10  Kapraun (1970)  n = 10  Sarma & Chaudhary (1975)  n = 10  Carter (1926)  n = 13  Foyn (1929)  U. lactuca  2n = 25  U. mutabilis U. mutabilis v. slender U. pertusa  Levan & Levring (1942)  n = 10  Sarma (1958a, 1964)  n  Kapraun (1970)  -  10  n - 13  Foyn (1934, 1959)  n = 8-9  Nordby (1974)  n  13  Linskens & Vennegoor (1967)  8  Hoxmark & Nordby (1974)  13  Yabu & Tokida (1960)  n n  : —  n = 9  Yabu & Park (1968)  Enteromorpha clathrata  n - 10  Kapraun (1970)  E. compressa  n = 9-10  Sarma (1958a)  E. compressa v. iingulata  n  10  Ramanthan (1939)  E. flexuosa  ? =  10  Kapraun (1970)  E. intermedia  n - 16  Sarma (1958b)  E. Iingulata  n = 10  Kapraun (1970)  E. linza  ?  =  Levan & Levring (1942)  ?  - 20  24-25  n  Comps (1961) Kapraun & Flynn (1973)  E. prolifera  !0 n = 10  E. ramulosa  n - 12  Sarma (1958b)  ? =  20  Kapraun (1970)  E. salina  n = 10  Kapraun (1970)  Monostroma fuscum  n = 9  Dube (1967)  Kapraun (1970)  189 period.  Thereafter, germlings were grown under a long day photoperiod i n  which the dark period ran from 12:00 noon to 7:00 pm.  Germlings were fixed  at h hour intervals between 12:00 noon and 4:00 pm. B. RESULTS Mitotic events i n species of Ulva and Chloropelta from the northeast Pacific generally agreed with reports by researchers for other ulvaceous algae.  Vegetative cells were usually uninucleate, though some, but by no  means a l l , rhizoidal cells were multinucleate.  In two isolates of U. fene-  strata started from parthenogenetic gametes, large round multinucleate cells about 25 um i n diameter were scattered among uninucleate cells i n the blade of germlings (Fig. 51f).  In these isolates and others started from gametes,  haploid and diploid sets of chromosomes were observed i n different cells i n the same germlings.  Other cells i n the same germlings were observed to con-  tain two sets of chromosomes undergoing division, each with i t s own spindle apparatus (Fig. 51e). These were either i n the same stage of mitosis or i n different stages. Mitotic divisions were generally observed a half hour to four hours after the end of the light period. mitosis.  Nuclear membranes persisted throughout  Nucleoli disappeared during gametogenesis but persisted through  early prophase during vegetative mitosis. The diminutive size of the chromosomes (0.5-2 um) and the persistent nucleolus and nuclear membrane made counting chromosomes d i f f i c u l t .  For each  species the number of chromosomes observed varied, even i n different cells from the same plant.  However, i n a l l species studied the chromosome numbers  were i n the same range.  Counts of haploid chromosomes ranged from 5 to 11  for U. californica, U. fenestrata, U. rigida, U. stenophylla, U. taeniata and Chloropelta caespitosa (Fig. 51). In most cells of these species 8 or 9  190  Figure 51.  Chromosome studies of Ulva and Chloropelta. a,b. Haploid sets of chromosomes i n Ulva C a l i f o r n i a . c,d. Haploid sets of chromosomes i n U. fenestrata. e f . A d i k a r y o t i c c e l l ( e i n metaphase) and a multinucleate c e l l ( f , i n prophase) i n parthenogenetic germlings of U. fenestrata. g,h. Haploid set (g) and d i p l o i d set (h) of chromosomes m U. stenophylla. i , j . Haploid sets of chromosomes i n U. taeniata" k , l . Haploid set (k) and d i p l o i d set (1, some chromosomes out of focus) i n Chloropelta caespitosa. a. Scale bar = 10 um. b - l . Same scale as (a). P = persistent nucleolus. 5  }  191  192 chromosomes were observed.  Germlings of U. fenestrata, U. stenophylla and C.  caespitosa started from parthenogenetic gametes gave haploid counts of 5 to 9 chromosomes and diploid counts of 12 to 18 chromosomes. C. DISCUSSION Mitotic events and chromosome numbers i n species of Ulva from the northeast Pacific were similar to those observed for other ulvaceous algae (Table 16).  However, the difficulty i n counting chromosomes and the similarities i n  chromosome number made chromosome studies an unlikely method for delimiting species. Of interest i s the variable nuclear state observed i n parthenogenetic germlings.  Parthenogenetic gametes either develop into gametophytes of the  same mating strain, diploid sporophytes, haploid sporophytes or t h a l l i that are both haploid and diploid and can produce both zoospores and gametes (Foyn, 1958, 1959; Hoxmark and Nordby, 1974; Hoxmark, 1975; Ltfvlie and Bryhni, 1978). Gametes of plus or + mating strains are more likely to produce diploid sporophytes than minus or -* mating strains (Hoxmark and Nordby, 1974).  Foyn (1962) also observed the formation of diploid sporophytes from  diploid gametes. The presence of parthenogenetic germlings with ln, 2n and n+n cells i n species from the northeast Pacific suggest that the doubling of the chromosome number i s progressive and does not occur i n the f i r s t or second nuclear divisions'of the settled gamete. This i s supported by Foyn's (1958) and Hoxmark's (1975) observations of parthenogenetic plants with both haploid and diploid cells.  Doubling of the chromosome number, referred to  as "diploidization" by Hoxmark and Nordby (1974), may occur through karyogamy following nuclear division without cytokinesis.  I f inhibition of cytokinesis  continued, then multinucleate cells such as were observed i n parthenogenetic germlings of U. fenestrata would form.  Factors responsible for initiating  193 and controlling "diploidization" are not clear (Hoxmark and Nordby, 1974).  194 VI. A.  GENERAL DISCUSSION SPECIES AFFINITIES The distromatic ulvaceous species from the northeast Pacific can be  divided into four groups based on similarities i n habitat, morphology, anatomy arid development. Ulva californica, Ulva scagelii, Ulva angusta The species i n this group grow i n the upper intertidal zone, are cuneate to narrowly oblanceolate, are relatively thin and generally have one pyrenoid in the single chloroplast of each c e l l .  The two species that have  been cultured, U. californica and U. scagelii, also show similar germination and developmental patterns. are  The primary differences between the three species  size and shape of the blade. The results presented in this thesis indi-  cate that these differences are related to differences i n environmental conditions . Specimens of U. californica from southern California form densely tufted turfs i n the upper intertidal zone.  Specimens of U. californica from  northern California and U. scagelii from Washington and British Columbia form mats i n the upper intertidal zone, but the t h a l l i are decumbent and solitary. In culture both species produce extensive basal disks that proliferate new upright blades to form tufts at temperatures above 15° C.  Below 15° C basal  disks are less extensive and the blades tend to be solitary.  The changes in  development at different temperatures relate well to changes in morphology and temperature in the northeast Pacific.  Along the Pacific coast of North  America the most abrupt change in surface water temperatures occurs at Point Conception, California.  North of Point Conception surface temperatures along  the open coast rarely exceed 15° C, whereas surface temperatures south of Point Conception are usually above 15° C (U.S. Dept. of Commerce, 1956). It  195  i s south of Point Conception that U. c a l i f o r n i c a usually forms densely ed t u r f s .  tuft-  The differences i n morphology and habit appear to r e f l e c t the  adaptation of t h a l l i to d i f f e r e n t c l i m a t i c conditions. Abbott and Hollenberg  As pointed out by  (1976, p. 6) f o r red algae, i n t e r t i d a l seaweeds i n  southern C a l i f o r n i a are predominately short, densely branched and often i n turfs.  North of Point Conception large f o l i o s e forms are more common.  turfs.are able to hold water among the branched or tufted t h a l l i and probably less susceptable tides.  The  are  to drying out or burning-off during summer low  These factors are less important north of Point Conception because  of the cooler summer temperatures and coastal fogs. of t h a l l i grown at r e l a t i v e l y high temperatures may the c l i m a t i c conditions i n southern C a l i f o r n i a .  The extensive basal disks also show adaptation to  In culture c e l l s of the disk  often produce new upright t h a l l i , p a r t i c u l a r l y at r e l a t i v e l y high temperatures. As has been suggested for a.similar turf species of Ulva from Morocco (Cauro, 1958), the basal disks are probably perennial and r e s i s t a n t to desiccation, providing a means of vegetative propagation  following summer burn-offs.  In culture both U. c a l i f o r n i c a and U. s c a g e l i i grow into long strapl i k e t h a l l i that reach lengths up to 15 cm.  Again, c l i m a t i c conditions prob-  ably account for the decrease i n blade length with a decrease i n l a t i t u d e (Fig.  10b).  Another factor that possibly a f f e c t s size and morphology i s  wave exposure.  Specimens of U. s c a g e l i i from protected shores i n the S t r a i t  of Georgia and Burrard I n l e t reach lengths of 15 cm or more.  Specimens from  exposed beaches on the west coast of Vancouver Island and from northern fornia are almost a l l under 3  Cali-  cm.  As discussed above, the morphological  differences between U. c a l i f o r n i c a  and U. s c a g e l i i can be r e l a t e d to environmental differences.  Because these  species also show s i m i l a r developmental patterns and are capable of hybridizing, i t i s proposed here that U. s c a g e l i i i s a synonym of the  196 older species, U. c a l i f o m i c a . I t i s also suggested here that U, angusta i s a synonym of U. c a l i f o m i ca.  Most of the specimens i d e n t i f i e d as U. angusta i n various herbaria (AHFH,  GMS,  UC, US) were found to be either U. stenophylla, U. taeniata or species  of Enteromorpha.  Doty (1947) examined one of the isotypes of U. angusta and  stated that the margins were sometimes hollow. to Enteromorpha.  He transferred this species  However, I examined holotype and isotype material and found  them to belong i n Ulva.  Occasionally the c e l l layers separated at the mar-;  gins a f t e r rehydration, but this also occurred i n other species more t y p i c a l of Ulva.  The type specimens of U. angusta show s i m i l a r i t i e s to U. c a l i f o m i -  ca and, as noted by Chihara (1968), to U. s c a g e l i i i n t h e i r thickness, c e l l dimensions and pyrenoid number.  Furthermore, they are almost i d e n t i c a l  morphologically to specimens of U. c a l i f o m i c a grown i n culture.  Setchell  and Gardner (1920b) gave the type habitat of U. angusta as shallow pools i n the upper i n t e r t i d a l zone.  Continued submergence of these plants could ex-  p l a i n why these specimens developed into long oblanceolate blades. Plants similar to U. c a l i f o m i c a i n habit, structure and development have been reported from other areas of the world.  Dangeard (1958b) tenta-:  t i v e l y assigned a diminutive tufted alga from near Dakar, Senegal, to U. califomica.  Chapman (1956) suggested that U. parva Chapman from New  Zealand  was c l o s e l y related to U. c a l i f o m i c a , d i f f e r i n g primarily i n thickness. Dangeard (1958a) and Chihara (1968) noted s i m i l a r i t i e s between U. l i n e a r i s Dangeard from Rabat, Morocco, and U. c a l i f o m i c a (U. s c a g e l i i i n Chihara, 1968).  Cauro (1958) described developmental patterns f o r U. l i n e a r i s and U.  gayral i i Cauro that were similar to that of U. c a l i f o m i c a .  Germination i n  these two species was usually d i r e c t , though germination by means of a germination tube d i d occasionally occur i n U. l i n e a r i s .  Cauro suggested that the  germination tubes only formed under unfavorable culture conditions (Chihara,  197 1968). However, Cauro reported that the cultures for both species were started from biflagellated swarmers. As reported i n Section IVB-la, parthenogenetic gametes from U. californica rarely formed.germination tubes.  The  same may apply to both U. linearis and U. gayralii. 2.  Ulva stenophylla, Ulva taeniata, Ulva costata, Ulva dactylifera, Ulva fasciata  These species show similarities in habit, morphology, anatomy and development. A l l are usually found on exposed beaches in the lower intertidal and subtidal zones, though they are sometimes found in the upper intertidal zone or in protected waters with high salinities.  The t h a l l i are composed  of simple or branched lacinae. With the exception of some specimens of U. fasciata, the lacinae have a thickened central midrib or costa and relatively thin margins and apex. Vegetative cells contain a single chloroplast, each with 2, 3 or more pyrenoids.  Ulva stenophylla, U. taeniata and U. fasciata  (from Hawaii) germinate directly, and in the f i r s t two species from the northeast Pacific single apical cells are retained until the germlings are 2 mm to a few cm in length. The morphology and anatomy of these species appear well adapted to survival on surf-swept beaches.  Linear lacinae present l i t t l e resistance to  moving water and shifting sand.  The thickened central axis adds strength to  theiacina, allowing i t in the instance of 'U. stenophylla to reach lengths of nearly 2 meters.  Occasionally, the midrib of these species i s reinforced by  the growth of rhizoidal protuberances from the axial cells between the c e l l layers .. 1  The morphological adaptability of these species is probably best  exemplified by U. taeniata. This species i s generally restricted to exposed sandy beaches.  The long lacinae remain intact even when buried with up to  The presence of a rhizoidal layer throughout the length of the lacinae of some specimens supports .Papenfuss' (1960) .conclusion that the taxon described as Letterstedtia belongs with Ulva.  1  198 10 cm or more of sand. The s i m i l a r i t i e s i n s t r u c t u r e and h a b i t i n d i c a t e that these species are closely related.  Three of the species, U, t a e n i a t a , U. costata and U. dacty-  l i f e r a , represent morphological v a r i a n t s of the same species. a.  Ulva stenophylla  I t s l i n e a r form, r u f f l e d margins, p l a n u l a r l o n g i t u d i n a l a x i s and l a c k of dentation are enough Lo make U. stenophylla one of the e a s i e r species of Ulva to i d e n t i f y on t h i s coast.  Some specimens c l o s e l y resemble U. t a e n i a t a ,  but examination of the base f o r dentation i s u s u a l l y s u f f i c i e n t to separate the two.  Unfortunately, an inaccurate species d e s c r i p t i o n and an a t y p i c a l  holotype has caused considerable confusion regarding the i d e n t i t y of t h i s species. pyrenoids.  S e t c h e l l and Gardner (1920a) described U. stenophylla as l a c k i n g However, subsequent examinations of the type (Chihara, 1969;  personal observations, F i g . 21d) and other specimens (Smith, 1947) have r e vealed the presence of pyrenoids.  Smith (1947) suggested that S e t c h e l l and  Gardner overlooked pyrenoids because t h e i r d e s c r i p t i o n was based e n t i r e l y on herbarium specimens.  The holotype of U. stenophylla (UC 98512) i s a broadly  lanceolate specimen s i m i l a r to specimens found i n quiet waters i n Barkley Sound. The isotype (UC 98511; F i g . 20d) and other specimens c o l l e c t e d by Gardner (UC 98477, 393944) are more t y p i c a l of the species.  The confusion  over the i d e n t i t y of t h i s species l e d Smith (1944) and Abbott and Hollenberg (1976) to consider t h i s species r a r e , "known only from the type specimens" (Smith, 1944).  However, t h e i r i l l u s t r a t i o n s and d e s c r i p t i o n s of U. angusta  as w e l l as specimens i n the GMS Herbarium l a b e l l e d as U. angusta represent U. stenophylla.  Doty (1947) i n t e r p r e t e d U, stenophylla as a broadly lanceo-  l a t e or e l l i p t i c a l species w i t h margins about the same thickness as the center.  A specimen (UC 307228) from Chetco Cove, Oregon, i d e n t i f i e d by Doty as  199  U. stenophylla, is actually a specimen of U. fenestrata. A species that bears a strong resemblance to U. stenophylla is U. arasakii Chihara (1969) from Japan.  Chihara compared the two but concluded  that they differed primarily because U. arasaki had 1-4 pyrenoids in the chloroplast of each c e l l whereas, according to his examination of the type, U. stenophylla had only 1 pyrenoid.  However, my studies of the type speci-  mens and numerous other herbarium and living specimens show that U. stenophylla usually has 2-3 pyrenoids in the chloroplast of each c e l l and less commonly 1 or 4 pyrenoids.  Chihara also noted that according to dimensions  given by Smith (.1947) gametes of U. stenophylla were smaller than gametes of U. arasaki. My measurements of gametes for Ulva species are consistently larger than Smith's, and for U. stenophylla are closer to the dimensions given by Chihara for U. arasaki. The primary difference between these two species is the type of germination.  Ulva stenophylla germinates directly,  whereas U. arasaki germinates by means of a germination tube. development in the two species is very similar.  Subsequent  The affinities of these  two species need to be studied further through culture and hybridization experiments.  Unfortunately, during the course of my research, live specimens  of U. arasaki could not be obtained. Two species from New Zealand also bear strong similarities to U. stenophylla.  Several specimens including the types of these two species, U.  geminoidea v. crispa (Chapman, 1956) and U. phyllosa (Chapman) Papenfuss (1960), were examined. as "L. phyllosaV.  Chapman (1952) based his genus Lobata on U. phyllosa  He justified the separation by claiming that reproductive  bodies were produced in the cells along the central axis. Papenfuss (1960) noted that Chapman's drawings of reproductive bodies resembled storage granules i n rhizoidal cells, and placed Lobata with Ulva. the holotype of Lobata phyllosa, which i s the type species  I found that  200 of the genus, possessed reproductive structures along the margins typical of the genus Ulva.  Reproductive bodies in the central cells were not observed.  At present information is lacking about the l i f e histories and development of U. geminoidea v. crispa and U. phyllosa. b.  Ulva taeniata  Ulva taeniata collected north of Point Conception is easy to recognize because of i t s linear spirally-twisted form and dentate margins.  Some speci-  mens develop planular midribs and ruffled margins similar to U. stenophylla, but close examination of the base and margins are usually sufficient to separate them. South of Point Conception the specimens are usually smaller and either lack or have reduced dentation.  In the past, most of these specimens  were placed in U. angusta or U. dactylifera.  Careful observation with a dis-  secting microscope or compound microscope usually reveals microscopic dentation along the margins.  It is important to distinguish between teeth formed  by divisions of marginal cells and teeth caused by erosion of the margins. Doty (1947) stated that dentation was visible in a photograph of the type of U. dactylifera (Setchell and Gardner, 1920a, Plate 26, Fig. 1).  Although the  type does have microscopic teeth (up to 70 um long), the macroscopic "teeth" visible in the photograph were caused by erosion. Setchell and Gardner (1920a) separated U. dactylifera from U. taeniata for the following reasons: 1) the absence of dentation; 2) an expanded basal portion with lacinae growing out from the margin; 3) a thicker midrib along the lacinae; 4) c e l l dimensions i n the midrib.  Examination of the type and  isotypes has revealed the presence of microscopic dentation similar to the dentation in morphologically more typical specimens of U. taeniata at a similar latitude. Herbarium studies indicate that the thicker midrib and d i f f e r ent c e l l dimensions in transverse section are related to an increase of tern-  201 perature south of Point Conception.  The majority of specimens, including  the isotypes of U. dactylifera, from southern California and Baja California lack the expanded base displayed by the type of U. dactylifera.  This morph-  ology appears to be atypical and i s not a sufficient reason for separating M* dactylifera from U. taeniata. Howe (1914) described specimens from Peru as U. fasciata f. costata based on the presence of pale thickened midribs or costae along the central axes of lacinae.  He noted that when costae were less distinct, "the resemb-  lance of the plants to the California U. fasciata f. taeniata Setchell, as exhibited in Phycotheca Boreali-Americana 862, i s marked, though they are less dentate-margined than that."  Hollenberg (1971), after examination of  a few costate specimens from southern California, designated this form as a species.  However, the plants he examined had costae that were darker than  the surrounding tissue (Hollenberg, 1971, Fig. 1).' In the AHF Herbarium there are a number of specimens from southern California and Baja California with either pale costae, dark costae or both to various degrees.  Most of  these plants have microscopic or macroscopic dentation and in no other way differ from other plants identifiable as U. taeniata.  The. costae i n these  specimens are caused either by the accumulation of starch or the lack of starch, and the development of large vacuoles i n the enlarged cells of the midrib. cells.  These conditions appear to reflect the physiological state of the For example i n cultures of Ulva where conditions inhibit rapid  growth, cells accumulate large quantities of starch.  Further support for  identifying U. costata with U. taeniata comes from the presence of pale costae i n ah isotype of the latter (US 57112; Fig. 23a).  However, of the speci-  mens of U. costata examined from Southern America (Peru, Chile) only the type material and a few specimens from Peru can be identified with U. taeniata. Other specimens more closely f i t U. fasciata Delile or U. nematoidea Bory  202 (see Levring, 1941). Chapman (1956) reported specimens of U. taeniata from New Zealand. Several specimens were examined from New Zealand during my study, and, a l though teeth were less distinct in these specimens, they were found to agree closely with U. taeniata from California.  The type specimen of U. brevisti-  pita Chapman (1956; CANTY, Laing H. 5421) was also examined and found to agree closely with U. taeniata. tains several inaccuracies.  Chapman's description of this species con-  He described this species as being 60 um thick,  with a c e l l length to width ratio in transverse section of 1.25.  He also re-  ported that U. brevistipita had "scarcely thickened" walls and adhered well to paper.  Examination of the type specimen revealed a lanceolate blade that  had microscopic teeth, was 75 um thick in the center and had a c e l l length to width ratio of 1.3 to 2.5.  Also, the c e l l walls in this specimen were  extremely thickened and the blade did not adhere to the herbarium paper. c.  Ulva fasciata  Ulva fasciata and U. taeniata show marked similarities, particularly in southern California where both species occur.  Ulva fasciata is a warm  water species occurring in tropical and subtropical waters around the world. U. taeniata is primarily a cold water species, but can grow at temperatures as high as 20° C.  Ulva taeniata is characterized by dentate margins, but  Delile (1813) also described U. fasciata as "briefly dentate".  Though the  teeth of U. fasciata, when present, are never as large or numerous as the teeth of U. taeniata growing north of Point Conception, in southern California this characteristic cannot be used to separate the two species. Howe (1914) noted that Montagne found in his studies of U. fasciata from Algeria that the margins of the lacinae were thickened. the margins are always much thinner than the central axis.  In U. taeniata The two specimens  203 of U. fasciata examined from southern California have thickened margins that differ only slightly from the central axis.  However, specimens from Cuba  (AHFH 58331) and Hawaii (UBC 58036) were found to have margins about half the  thickness of the central axis.  Setchell and Gardner (1920a) separated  U. taeniata from U. fasciata because the former was usually crisply ruffled or spirally twisted, whereas U. fasciata from other areas was almost always planular. My observations of the two species suggest that U. fasciata can be separated from U. taeniata by i t s planular lacinae with margins about the same thickness as the central axis.  U. fasciata also tends to be highly  branched from the base into long linear lacinae of similar lengths.  With  few exceptions, U. taeniata tends to be sparsely and irregularly branched. 3.  Ulva fenestrata, Ulva expansa, Ulva lobata, Ulva rigida, Ulva conglobata  These species are orbicular, ovate, irregularly lobed or expanded. They vary greatly in their c e l l dimensions and usually have 1, 2, 3 or more pyrenoids in the single chloroplast of each c e l l . a.  Ulva fenestrata  Setchell and Gardner (1920a, 1920b) noted similarities between U. fenestrata, U. expansa and U. lobata.  They separated U. lobata from U.  expansa because of i t s smaller size, i t s thicker blade and because i t was less ruffled.  Both species were distinguished from U. fenestrata because  they lacked regular perforations.  Vinogradova (1974) stated that perfora-  tions i n U. fenestrata from the northwest Pacific were caused by grazing molluscs such as Littorina and were not a valid taxonomic characteristic. Her observations are supported by my own and by the lack of perforations in  cultured plants and plants growing epiphytically on Nereocystis pneumatocysts or stipes.  The separation of U. lobata from U. expansa or U. fenestra-  ta on the basis of size, thickness or presence of lobes no longer appears valid because of the large amount of variation noted for plants grown under different environmental conditions. I have not observed any specimens of U. expansa or U. lobata from the northeast Pacific that did not f i t into the morphological and anatomical range of U. fenestrata. It is d i f f i c u l t to determine the distribution of U. fenestrata. In most coastal areas there are species that closely resemble U. fenestrata. Chapman (1956) reported U. lobata from New Zealand, and Saifallah and Nizamuddin (1977) reported U. fenestrata from Pakistan.  The type locality of U.  lobata is reported to be Chile (Setchell and Gardner, 1920a); however, the specimen illustrated by Kiitzing (1849) as Phycoseris lobata (L 4114-3; Fig. lid) has written on i t : "C.B. Spei".  According to a personal communication  from Dr. G. M. Lokhorst to Dr. R. F. Scagel, this means: "Cape the Good Hope, South Africa".  Obviously, extensive culture and hybridization studies are  required to determine the relationships of expanded t h a l l i from various geographic localities. b.  Ulva rigida  Ulva rigida is a ubiquitous species found primarily in tropical and subtropical waters. Although the concept of U. rigida has varied greatly, i t is now considered by most phycologists to be characterized by lobed or expanded blades with dentate margins (Bliding, 1968).  In the northeast  Pacific this name has been used for thick, ovate or deeply divided plants, ranging in distribution from Alaska to Mexico (Setchell and Gardner, 1920b; Smith, 1944; Scagel, 1966; Abbott and Hollenberg, 1976).  In not one of  these floras have teeth been listed as a species characteristic, ;:.  205 though Abbott and Hollenberg illustrated a dentate specimen (1976, Fig. 41). Yendo (1916) noted that "the plant which passes as U. lactuca var. rigida among American botanists appears to me certainly different from U. rigida Ag."  Although this appears true for most specimens identified with this  species, dentate specimens from southern California closely resemble U. r i g i da from other areas and most certainly belong with this species. c.  Ulva conglobata  Ulva conglobata was described by Kjellman (1897) for a tufted plant growing in the upper intertidal zone i n Japan (see Okamura, 1918). (1916) considered this species to be a synonym of U. rigida.  Yendo  He noted that  U. fasciata f. caespitosa Setchell from California closely resembled U. conglobata f. densa Kjellman and suggested that this taxon should also be combined with U. rigida.  Setchell and Gardner (1920b) also noted the similari-  ties between U. fasciata f. caespitosa and U. conglobata; however, they referred these species to U. lactuca. Specimens of U. conglobata from the northeast Pacific show similarities to both U. fenestrata and U. rigida.  They differ from the latter by the lack  of marginal dentation. Unlike U. taeniata, the teeth in U. rigida do not appear to be influenced by temperature (Rhyne, personal communication), at least for specimens from the northwest Atlantic. bly be a high intertidal form of U. fenestrata.  U. conglobata could possiThis i s supported by the  occasional formation of tufted plants similar to U. conglobata i n culture from isolates of U. fenestrata.  However, as noted i n Section IVD-2 gametes  of U. conglobata failed to mate with gametes of U. fenestrata.  The results  from this experiment were inconclusive but suggest that U. conglobata may be genetically distinct from U. fenestrata.  206 4.  Chloropelta caespitosa  Chloropelta caespitosa superficially resembles tufted species of Ulva from southern California such as U. califomica and U. rigida.  However, C.  caespitosa differs from species of Ulva i n i t s peltate blade and distinctly different development. From the discussion in Section IVE-2 i t is clear that although Chloropelta i s a different taxon from Ulva, i t has close affinities with members of the Ulvaceae. At present, development, l i f e histories and the method of release of swarmers are the primary criteria for separating families within the Ulvales (Bliding, 1968; Gayral, 1971; Tatewaki, 1972; Vinogradova, 1974). By these criteria Chloropelta is closest to the Ulvaceae.  The strong similarities in development between Cloropelta and  Ulvaria (Dube, 1967) suggest to me that Chloropelta may have evolved from an Ulvaria-like ancestor.  Ulvaria is restricted to cold water regions, whereas  Chloropelta has only been found in warm-temperate waters.  The ability of  cells to divide longitudinally to form a distromatic blade may have developed in response to climatic pressures.  The distromatic campanulate blade and  tufted habit of Chloropelta no doubt increases.its resistance to desiccation as has been suggested for U. califomica in Section IVA-1.  It is unlikely  that a monostromatic ulvaceous alga such as Ulvaria could survive in the upper intertidal zone of subtropical or tropical regions.  207 B.  KEY TO THE DISTROMATIC ULVACEOUS ALGAE FROM THE NORTHEAST PACIFIC Species of Ulva and Chloropelta are morphologically plastic and often  overlap i n taxonomic characteristics.  When collecting Ulva or Chloropelta  several mature specimens from each population should be collected, and environmental factors such as water temperature, salinity, exposure to surf and tidal position should be noted.  Identifications using the following key  should be confirmed by comparing specimens to species descriptions and f i g ures.  For studies requiring positive identifications isolates should be  cultured and their developmental patterns checked against those described for the different species (Section IV). 1. Thallus either a distromatic vesicle a few mm i n diameter or a peltate, distromatic blade, occasionally torn to the base Chloropelta caespitosa 1. Thallus a distromatic blade with a basal holdfast, though often with new blades proliferating from the base  2  2. Thallus cuneate, oblanceolate, linear or lanceolate; ± branched...3 2. Thallus orbicular, ovate, irregularly lobed or expanded  6  3. Thallus spirally twisted, often branched and marginally dentate, in water of temperatures above 18° C the teeth microscopic or occasionally absent  Ulva taeniata  3. Thallus generally not spirally twisted, though often with densely ruffled margins; marginal dentation absent  4  4. Thallus with several long, linear lacinae originating from near the base; planular throughout; south of Point Conception, California .. Ulva fasciata 4. Thallus usually not branched at base, though occasionally with a single fork; planular or with ruffled margins  5  208 5.  Thallus cuneate to oblanceolate, always expanding in width towards the apex; planular or slightly ruffled; mature thallus less than 1 cm to 25 cm long; chloroplasts usually with one pyrenoid.... Ulva califomica  5.  Thallus linear to lancolate, almost always tapering at the apex; often with a thickened planular midrib and densely ruffled margins; mature thallus 20 to 180 cm long; chloroplasts usually with 2-3 pyrenoids  ....  Ulva stenophylla 6.  Thallus with microscopic marginal dentation; often lobed and densely tufted; growing in the mid to upper intertidal zone .. Ulva rigida  6.  1  Thallus without marginal dentation; orbicular, ovate,irregularly lobed or expanded, often with numerous perforations Ulva. fenestrata  ^ l s o see discussion of Ulva conglobata Kjellman in Section VTA-3c.  1  209 C.  TAXONOMIC CONCEPTS ULVALES Blackman and Tansely (1902) 1  This order classically includes biseriate or parenchymatous t h a l l i one to two cells thick attached by rhizoids or a basal disk. Cells of the thallus are primarily uninucleate with single parietal chloroplasts usually containing one or more pyrenoids.  Sexual reproduction i s by biflagellated iso-  gamous or anisogamous gametes, and asexual reproduction i s usually by quadriflagellated or occasionally biflagellated zoospores.  Germination of the re-  productive cells is either direct or by germination tubes.  Life histories  can be isomorphic or hetermomorphic, and developmental patterns are variable. ULVACEAE Lamouroux orth. mut. Dumortier (1822) This family includes biseriate and parenchymatous t h a l l i one to two cells thick.  Life histories consist of an alternation of isomorphic unisex-  ual gametophyte and sporophyte stages, though one or the other stage i s occasionally lost.  Reproductive swarmers are released from sporangia and gamet-  angia through circular or e l l i p t i c a l pores.  Reproductive cells germinate  directly or by means of a germination tube into an upright uniseriate filament and a prostrate ± rhizoidal attaching system.  Through longitudinal divisions  at right angles to the surface the germling develops into a biseriate (e.g. Percursaria) or a multiseriate filament. In most genera continued longitudinal divisions lead to a tubular saccate germling one c e l l thick.  The mono-  stromatic tubular germling either remains saccate (e.g. Blidingia, Enteromorpha) , tears open to form a flattened monostromatic blade (e.g. Ulvaria) or decent, but as yet incomplete work, suggests that this order should be modified to include filamentous and_parenchymatous algae that divide vegetatively by means of a precocious furrow and differ from other green algae i n the structure of the reproductive cells (Stewart and Mattox, 1975a, 1978).  210 collapses to form a distromatic blade (e.g. Ulva).  In Chloropelta cells of  the monostromatic tubular germling undergo a single longitudinal division i n a plane parallel to the surface to produce a distromatic tubular germling that eventually tears to become a peltate blade.  ULVA Linnaeus (1753) The thallus is a flattened, foliose, distromatic blade that is usually attached at the base by rhizoidal cells.  Vegetative cells are uninucleate,  though rhizoidal cells are occasionally multinucleate, and have single parietal chloroplasts with one or more pyrenoids.  Sporangia and gametangia  form either throughout the blade or are restricted to the margin. zygotes and parthenogenetic  Zoospores,  gametes germinate directly or by a germination  tube and develop into a monostromatic tubular germling. tubular germling produces a flattened distromatic blade.  Collapse of the The c e l l layers  remain separated by a mucilaginous matrix, and the blade expands by diffuse transverse divisions within each c e l l layer.  211  1. Ulva califomica Wille i n Collins, Holden and Setchell, 1899. TYPE LOCALITY: On rocks near high water mark, Pacific Beach, south of La Jolla, California. TYPE MATERIAL: Lectotype: NY; no date of collection.  Isotypes:  distributed as P.B.- A. no. 611. REFERENCES: Wille, i n Collins, Holden and Setchell, 1899, Fasc. 13, no. 611. Collins, 1903, p. 9. Collins, 1909, p. 215-216. Setchell and Gardner, 1920b, p. 264. Dawson, 1945, p. 23. Dawson, 1947, p. 8. Doty, 1947, p. 11, Plate 2, Figs. 6-10. Dangeard, 1958a, p. 166-167. Dawson, 1959a, p. 186-188, 190. Dawson, 1960, p. 31. Dawson, 1961, p. 374. Sparling, 1971, p. 236. Abbott and Hollenberg, 1976, p. 78, 80, Fig. 35. Phinney, 1978, p. 102. SYNONYM: Ulva scagelii Chihara, 1968. TYPE LOCALITY: Kitsilano Beach, Vancouver, British Columbia. TYPE MATERIAL: Holotype: TNS-AL 10011, collected June 29, 1968. Isotypes: UBC 34568, 34569, 34570; UC M110589.  REFERENCES: Chihara, 1968, p. 87-102, Figs. 3-8'.  212  PROBABLE SYNONYMS: Ulva angusta Setchell et Gardner, 1920a. TYPE LOCALITY:  Published as Moss Beach, San Mateo Co., California,  but the holotype i s labeled as being from Sausalito, Marin Co. The isotype labels agree with the published locality. TYPE MATERIAL: Holotype:  UC 205623, collected April, 1919.  Isotypes:  AHFH 58854, 60478, UW 64242, US 57109. REFERENCES: Setchell and Gardner, 1920a, p. 283, Plate 27, Plate 31, Fig. 1. Setchell and Gardner, 1920b, p. 264-5, Plate 22, Plate 26, Fig. 1. Ulva linearis.Dangeard, 1957. TYPE LOCALITY: Rabat, Morocco. REFERENCES: Dangeard, 1957, p. 1591-2. Dangeard, 1958a, p. 28-31, Figs. 9-10. Cauro, 1958, p. 99-101, Plates 3-4. Gayral, 1960, p. 85-95, Plate 1, Plate 3, Figs. a,b. DISTRIBUTION: N.E. Pacific: Alaska Peninsula to Isla Magdalena, Baja California. N.E. Atlantic: Morocco? REPRESENTATIVE SPECIMENS: ALASKA: Khantaak I s i . , 8-VI-60, UBC 9231, 9232. BRITISH COLUMBIA.: Brockton Point, Vancouver (49°18'N, 123°7'W), 16-V-76, UBC 58356 (U285); Ferguson Point, Vancouver (approx. 49°18'N, 123°13'w), 24-VII-68,  213 UBC 34826; English Bay, Vancouver (49°17'N, 123°14'W), 8-VTI-76, UBC 58076 (U302); Kitsilano Beach, Vancouver (48°17'N, 123°23'W), 29-VT-68, UBC 34568, 34569, 34570; Departure Bay, Vancouver I s l . (49°10'N, 123°55'W), 17-VI-76, UBC 58077 (U301); Sidney Harbor, Vancouver I s l . (approx. 48°39'N, 123°55'W), 8-X-76, UBC 58359; Botany Beach, Port Renfrew, Vancouver I s l . (approx. 48°33'N, 124°28'W), 10-VII-76, UBC 58346 (U308); Victoria Breakwater, Vancouver I s l . (approx. 48°25'N, 123°21*W), 23-V-63, UBC 18430, 18431. WASHINGTON: W. side of Whidbey I s l . (approx 48°12'N, 122°45*W), 23-VII-77, UBC 58353, 58354 (U336). CALIFORNIA: S. of San Gregorio Beach (approx. 37°20'N, 122°28'W), 31-XII-75, UBC 58347 (U266.5); Point Joe, Pacific Grove (approx. 36°37'N, 121°54'W), 25-VII-76, UBC 58349, 58350 (U303); Montana de Oro State Beach, San Luis Obispo Co. (approx. 35°15'N, 120°51'W), 11-74, Setzer 8080 (AHFH); Montecito (approx. 34°25"N, 119°34'W), 5-II-59, AHFH 70000; West Malibu (approx. 34°03'N, 118°57'W), 17^X1-56, AHFH 63053; Point Mugu (34°06'N, 114°07.5W), 26-X-57, AHFH 66940; Pitas Point (34°17.2'N, 119°23.2'W), ?, AHFH 67867; Sunset Blvd., Los Angeles (approx. 34°01'N, 118 29'W), 14-11-58, AHFH 67911, 15-XI-56, AHFH 63176; Wood's Cove, 0  Laguna Beach (33°32'N, 117°46'W), 26-V-76, UBC 58075 (U290); N. of Scripts Pier, La Jolla (approx. 32°51'N, 117°16'W), 27-V-76, UBC 58344 (U295); Pacific Beach, La Jolla (approx. 32°50'N, 117°17'W), ?, NY (Lectotype), P.B-A. 611 (isotypes), UC 77858.  214  2. Ulva conglobata Kjellman, 1897. TYPE LOCALITY: Yokohama, Goto and Amaska, Japan. TYPE MATERIAL: The type material could not be located. REFERENCES: Kjellman, 1897, p. 11-14, Plate 2, Figs. 1-11, Plate 3, Figs. 15-18. Yendo, 1916, p. 243~4. Okamura, 1921, p. 58-9, Plate 165, Figs. 1-10. Fujiyama, 1950, p. 222-3. Yoshida, 1965, p. 8-14. SYNONYMS: Ulva fasciata f. caespitosa Setchell TYPE LOCALITY:  1  "Forming a close covering on sandy rocks, midway of  the l i t t o r a l zone," Pacific Grove, California. TYPE MATERIAL: P.B. - A. no. 809, collected May, 1900. REFERENCES: Setchell, i n Collins, Holden and Setchell, 1901, Fasc. 17, no. 809. Setchell and Gardner, 1920b, p. 270. DISTRIBUTION: N.E. Pacific: Vancouver Island, B.C. to Monterey, California? N.W. Pacific:  Japan  REPRESENTATIVE SPECIMENS: BRITISH COLUMBIA: Flores I s i . , Clayoquot Sound, Vancouver I s i . (49°26.65 N, 126°14.0'W), I  13-V-75, UBC 58186 (U201); S.E.. side of Diana I s i . , Barkley S. 1  This name lacks a published diagnosis and i s therefore invalid.  Vancouver I s i . 48 50.1*N, 125°10.1*W) o  3  17-VI-75, UBC 58190 (U234).  OREGON: Yaquina Head (44°41'N, 124°05'W) 22-IIX-75, UBC 58195 (U260); S. of 5  Newport (approx. 44°39'N 124°02'W) 22-IIX-75, UBC 58187 (U258). S  CALIFORNIA: Moss  Beach (approx. 37°35'N, 122°30'W), 28-IV-75, UBC 58188, 58189  (U194);  P o i n t Joe, P a c i f i c Grove (approx. 36°37'N, 121°54'W),  5-VII-28, AHFH 78344; P a c i f i c Grove (approx. 36°37'N, 121°54'W), V-1900, GMS 8044, P.B.A. 809 (UBC).  216  3. Ulva fasciata Delile, 1813. TYPE LOCALITY: Port of Alexandria, Egypt. TYPE MATERIAL:  Could not be located.  REFERENCES: Delile, 1813, p. 297, Plate 58, Fig. 5. Chapman, 1956, p. 396. Dangeard, 1958a, p. 23-28, Figs. 5-7. Gayral, 1958, p. 150-1, Plate 4. Taylor, 1967, p. 66. Krishnamurthy and Joshi, 1969, p. 126, Figs. 3,9,15. Kapraun, 1970, p. 210, Figs. 1,2,41-43. Saifullah and Nizamuddin, 1977, p. 522, Plate l c , Fig. 6. DISTRIBUTION World-wide i n tropical waters. N.E. Pacific:  only two herbarium specimens from southern California  were observed (P.B.-A. No. 221b at UBC, unnumbered specimen i n the Setzer Herbarium).  217  4.  Ulva fenestraLa Postcls et Ruprecht, 1840. TYPE LOCALITY: Port St. Petri and Pauli, Kamtschatka. TYPE MATERIAL: Holotype:  LE; UBC 57002 (photograph and small pieces  of the type); no date of collection.  Isotype: LD 14419.  REFERENCES: Postels and Ruprecht, 1840, p. 21, Plate 37. Setchell and Gardner, 1920b, p. 267. Nagai, 1940, p. 8-9. Sandborn and Doty, 1944, p. 24. Dawson, 1947, p. 9. Doty, 1947, p. 9-10, Plate 2, Fig. 3. Scagel, 1957, p. 43. Dawson, 1961, p. 374. Dawson, 1965,  p.-8.  Scagel, 1966, p. 59, Plate 29, Figs. C-E. Chihara, 1968, p. 87-102, Figs. 1,2 and 8. Johansen, 1971, p. 66. McRoy et a l . , 1971, p. 7. Vinogradova, 1974, p. 70-4, Plate 19, Figs. 1-6, Plate 10, Figs. 1-9. Lindstrom, 1977, p. 40-41. Phinney, 1978, p. 1-2. SYNONYMS: Ulva expansa (Setchell.) Setchell et Gardner, 1920a. TYPE LOCALITY: "Floating in great abundance and apparently attached to sandy rocks, Monterey", California. TYPE MATERIAL:  Lectotype:  UC 98481; collected June 4, 1901  Isotype:  218 UC 98482. REFERENCES: Setchell, i n Collins, Holden and Setchell, 1905, Fasc. D. no. LXXVII (as Ulva fasciata f. expansa). Collins, 1909, p. 216 (as U. fasciata f. expansa). Setchell and Gardner, 1920a, p. 284-285. Setchell and Gardner, 1920b, p. 268. Sandborn and Doty, 1944, p. 24. Smith, 1944, p. 46. Dawson, 1945, p. 23. Dawson, 1946b, p. 170. Dawson, 1947, p. 9. Doty, 1947, p. 10. Dawson, 1954, p. 101. Scagel, 1966, p. 58-9, Plate 29, Figs. A,B., Norris, 1970, p. 48-49. Norris and Abbott, 1972, p. 88. Abbott and Hollenberg, 1976, p. 80-3, Fig. 38. Phinney, 1978, p. 102. Ulva fasciata f. lobata Setchell, 1901. TYPE LOCALITY: On rocks i n the lower intertidal zone, Pebble Beach, Carmel Bay, California. TYPE MATERIAL: Holotype:  UC 98491; collected June 17, 1901. Isotypes:  P.B.-A. no. 863. REFERENCES: Setchell, i n Collins, Holden and Setchell, 1901, Fasc. 18, no. 863. Collins, 1903, p. 10. Collins, 1909, p. 216.  Setchell and Gardner, 1920a, p. 284 (this and the following references as Ulva lobata (Kutzing) Setchell et. Gardner). Setchell and Gardner, 1920b, p. 268~9. Smith, 1944, p. 46-7, Plate 4, Figs. 4 - 5 . Dawson, 1945, p. 23. ?Taylor, 1945, p. 43. ?Dawson, 1946b, p. 170. Doty, 1947, p. 10. ?Dawson, 1954, p. 101. ?Chapman, 1956, p. 394-5. TDawson, 1957, p. 4. Dawson, 1959a, p. 186, 188. Dawson, 1965, p. 8. Strand, et a l . , 1966, p. 487-500. Norris, 1970, p. 50, Plate 19C. Abbott and Hollenberg, 1976, p. 85, 87, Fig. 40. Phinney, 1978, p. 102. Ulva pertusa Kjellman, 1897. TYPE LOCALITY: Hakodate, Yenoshima and Yokahama, Japan. TYPE MATERIAL:  could not be located.  REFERENCES: Kjellman, 1897, p. 4, Plate 1, Figs. 1-5, Plate 3, Figs. 1-8. Okamura, 1921, p. 79-81, Plate 169, Fig. 8, Plate 170, Figs. 1-14. Yamada and Saito, 1938, p. 36-40. Nagai, 1940, p. 8. Segawa, 1959, p. 3, Plate 2, Fig. 8. Vinogradova, 1974, p. 70.  220  DISTRIBUTION N.E. Pacific:  Alaska to southern California.  N.W. Pacific:  Kamchatka to Taiwan(?)  REPRESENTATIVE SPECIMENS: ALASKA:  1  Shapard Point, Orca Bay, Prince William Sound (approx. 60°30'N, 145° 40'W), 31-V-65, M 155339; Sitka (approx. 57°3'N, 135°18'W), 19-VII-17, UC 205680. BRITISH COLUMBIA: Hope Island (approx. 50°58'N, 127°55'W), 15-IV-75, UBC 58227 (U181); Squire Point, Call Inlet (50°35'N,  126°09'W), 17-IV-75, UBC 55226  (U183); I s i . S.E. of Grassy I s i . , at mouth of Kyuquot S., Vancouver I s i . (49°55.4'N, 127 15.0'W), 14-V-75, UBC 58212(U205); Flores I s i . , O  Clayoquot S., Vancouver I s i . (49°26.65'N, 126°14.0'W), 13-V-75, UBC 58216 (U200); Brockton Point, Vancouver (49°18'N, 123°07'W), 3-XI-74, UBC 58332 (U140); Belle Chain Islets, Strait of Georgia (49 08.42', 123°40.24'W),29-X-73, UBC 58201 (U105); S.E.of Diana O  I s i . , Barkley S., Vancouver I s i . (48°50.1'N, 125°10.1'W), 15-11-76, UBC 58113 (U267); S.E. of Aguilar Point, Barkley S., Vancouver I s i . (48°50.4'N, 125°10.9°W), 27-VT-73, UBC 58101 (U60); Scott's Cove, Barkley S., Vancouver I s i . (48°50.1'N, 125°08.72*W), 15-IX-74, UBC 58338 (U136); Sooke Harbor, Vancouver I s i . (48°21.6'N, 123°42.5'W), 31-111-71, UBC 58107, 58108. WASHINGTON: Utsalady, Camano I s i . (approx, 48°10'N, 122°31'W), VII-08, UC 132729; 1  In addition to those listed, there are numerous specimens from Alaska and B.C. in the UBC herbarium.  221  Steam Boat I s i . , Thurston Co., 9-VH-67, UW 244339; Lincoln Park, Seattle (approx. 47°30'N, 122°22'W), 14-VIII-55; Willapa Harbor (approx. 47°00'N, 124°00'W), ?, UW 249554 OREGON: Yaquina Bay (approx. 44°39'N, 124°02'W), 9-IX-65, OSU 21; Chetco Cove, Brookings (approx. 42°04'N, 124°16'W) 5-VII-44, DS 307228. 5  CALIFORNIA: Sausalito, San Franciso Bay (approx. 37°51'N, 122°29'W), V-20, UW 137763; Elkhom Slough, Moss Landing (approx. 36°48'N, 121°47'W), 3-X-69, GMS 10858; Monterey Harbor (approx. 36°48'N, 122 01'W), O  16-VTI-42,. GMS 8028; Pebble Beach, Carmel (approx. 36°33'N, 121°55.9' W), 23-V-71, GMS 11655, 7-XI-75, UBC 58229 (U264); Danna PointHarbor (approx. 33°24'N, 117°40'W), 26-V-76, UBC 58230.  222 5. Ulva rigida C. Agardh, 1822. TYPE LOCALITY:  Cadiz, southern Spain (see Papenfuss, 1960, p. 305).  TYPE MATERIAL: Lectotype: at Lund (LD). REFERENCES: Agardh, C , 1822, p. 410-11. Setchell and Gardner, 1920b, p. 269-70. Dawson, 1944, p. 202. Dangeard, 1958a, p. 22-3. Gayral, 1958, p. 148, Plate 3. Dangeard, 1959, p. 141-5, Figs. 10-11. Papenfuss, 1960, p. 305, Fig. 4, Plate 1, Fig. 11. Gayral, 1961, p. 223~8. Bliding, 1968. Krishnamurthy and Joshi, 1969, p. 124, Fig. 1,7,13. Vinogradova, 1974, p. 69~70, Plate 18, Figs. 1-8. Abbott and Hollenberg, 1976, p. 87, Fig. 41. Saifullah and Nizamuddin, 1977, p. 224, Plate 2c, Fig. 15. DISTRIBUTION: World-wide. N.E. Pacific: Southern California and Mexico. REPRESENTATIVE SPECIMENS: CALIFORNIA: Lechuza Point, 12-XI-58, AHFH 69124; Lunada Bay, 30-XI-57, AHFH 65905; Catalina I s l . (approx. 33°32'N, 118°29'W), 23-23-111-48, AHFH 26608, 5-IV-70, DS 12209; La Jolla Cove, La Jolla (approx. 32°51*N, 117°16'W), 26-V-76, UBC 58184,58185 (U291); Bird Rock, Pacific Beach (approx.  223  32 50'N, 117 17'W), 26-V-76, UBC 58183 (U294). U  BAJA CALIFORNIA: Punta San Eugenio, l-XI-51, US 41728; Punta Frailes, 13-111-49, US 41546; Isla Margarita, 9-III-49, US 38738.  Ulva stenophylla Setchell et Gardner, 1920a. TYPE LOGALITY:  Floating, Monterey, California.  TYPE SPECIMENS: type:  Holotype:  UC 98512; collected June 10, 1901. Iso-  UC 98511.  REFERENCES: Setchell and Gardner, 1920a, p. 282, Plate 26, Fig. 2, Plate 29. Setchell and Gardner, 1920b, p. 271, Plate 21, Fig. 2, Plate 24. Smith, 1944, p. 45, 47, Plate 4, Fig. 1-3 (as Ulva angusta). Dawson, 1947, p. 9. Smith, 1947, p. 80-7, Figs. 7-13. Smith, 1955, p. 62, Fig. 24. Papenfuss, 1960, p. 308. Dawson, 1961, p. 374. Lee, 1965, p. 88-9, 104. Abbott and Hollenberg, 1976, p. 87, Fig. 42, p. 78, Fig. 34 (as U. angusta). Phinney, 1978, p. 102. PROBABLE SYNONYMS: Ulva phyllosa (Chapman) Papenfuss, 1960. TYPE LOCALITY: Tauranga Bay, New Zealand. TYPE SPECIMEN:  Holotype: CANTY 38129; collected Nov. 7, 1942.  REFERENCES: Chapman, 1952, p. 49, Fig. 3 (as Lobata phyllosa). Chapman, 1956, p. 398, Fig. 41 (as L. phyllosa). Papenfuss, 1960, p. 312. Ulva arasakii Chihara, 1969.  TYPE LOCALITY:  Inuwaka, Choshi, Chiba-ken, Japan.  TYPE MATERIAL: Holotype: TNS; collected May L, 1965. REFERENCES: Chihara, 1969, p. 849-62, Figs. 1-3, Plate 1. DISTRIBUTION: N.E. Pacific: Vancouver Island, British Columbia to Santa Barbara, California. N.W. Pacific:  Choshi Peninsula, Japan (as U. arasakii)?  S.W. Pacific:  New Zealand (as U. phyllosa)?  REPRESENTATIVE SPECIMENS: BRITISH COLUMBIA: E. side of Diana I s i . , Barkley S., Vancouver I s i . (48°51'N, 125°11'W), 17-1-76, UBC 58032, 16-IV-76, UBC 58033 (U276); S.E. of Diana I s i . , Barkley S., Vancouver I s i . (48°50.1'N, 125°101'W), 13-IX-74, UBC 58080 (U133), 13-V-76, UBC 58034 (U284); Scott's Cave, Barkley S., Vancouver I s i . (48°50.1'N, 125°08.72'W), 17IX-73, UBC 58069, 18-VIV-74, UBC 58082 (U121), 3-IV-77, UBC 58041, 58042 (U324); Grappler Inlet, Bamfield, Vancouver I s i . (48°49.94*N, 125°06.94'W), 16-VT-75, UBC 58048, 22-VII-75, UBC 58027, 58028, 58029; Brady's Beach, Bamfield, Vancouver I s i . (48°49.74'N, 125°09'W), 24-VI-75, UBC 58086 (U238), 13-V-76, UBC 58022 (U282); Second Beach, Bamfield, Vancouver I s i . (48°48.85'N, 125°09.7'W), 10-VII-75, UBC 58021 (U247); Whiffen Spit, Vancouver I s i . (approx. 48°21'N, 123°43'W), 14-VII-73, UBC 55731, 55732. CALIFORNIA: Buhue Point, Humboldt Bay (approx. 40°48'N, 124°25'W), 29-VII-72, UBC 47117, 47118; Bolinas, (approx. 38°54'N, 122°42'W), ?-V-03,  UC 393944; Durbury Reef (approx. 38°54'N, 122°42'W), 29-V-03, UC 98477; Monterey (approx. 36°48'N, 122°0i'W), 10-VT-Ol, UC 98511 (Isotype); Coal OiL Point, Santa Barbara Co, (approx. 34°26'N, 119°43'W), 6-VII-70, AHFH 76120; Santa Barbara (approx. 34°26'N, 114°43'W), 26-XII-32, AHFH 78392. NEW ZEALAND: Steuart I s l . (approx. 46°50'S, 168°36'E), 6-V-45, Auckland 0100S (Lobata phyllosa); Tauranga Bay, Westport, West Coast of South Island (approx. 43°15'S, 167°00'E), 7-X-42, CHR 38129 (holotype of Lobata phyllosa).  227 7. Ulva taeniata (Setchell) Setchell et Gardner, 1920a. TYPE LOCALITY:  "On sandy rocks, i n small tideways, lower l i t t o r a l and  upper sublittoral zones, Monterey, California." TYPE SPECIMENS: types:  Holotype: UC 98493; collected June 11, 1901. Iso-  US 57112; P.B.A. no. 862.  REFERENCES: Harvey, 1858, p. 58~9 (as U. fasciata, i n part). Harvey, 1862, p. 161 (as U. fasciata). Anderson, 1891, p. 218 (as U. fasciata). Setchell, i n Collins, Holden and Setchell, 1901, Fasc. 18 no. 862 (as U. fasciata f. taeniata). Collins, 1903, p. 10 (as U. fasciata f. taeniata). Collins, 1909, p. 216 (as U. fasciata f. taeniata). Setchell and Gardner, 1920a, p. 286-7, Plate 28. Setchell and Gardner, 1920b, p. 273, Plate 23. Sanborn and Doty, 1944, p. 12,20,24. Smith, 1944, p. 48, Plate 3, Figs. 1-3. Dawson, 1946a, p. 59-64. Dawson, 1946b, p. 170. Dawson, 1947, p. 9. Doty, 1947, p. 8-9, Plate 2, Figs. 11-12, Plate 4, Figs. 3-4. Smith, 1947, p. 8-9, Figs. 26-7. Dawson, 1954, p. 101. Chapman, 1956, p. 387, ,Fig. 311. Dawson, 1959a, p. 186. Papenfuss, 1960, p. 308, Plate 5, Fig. 19. Dawson, 1961, p. 374. Widdowson, 1965, p. 1427.  228 Norris and Abbott, 1972, p. 88. Abbott and Hollenberg, 1976, p. 87, Fig. 43. Phinney, 1978, p. 102. SYNONYM: Ulva dactylifera Setchell et Gardner, 1920a. TYPE LOCALITY:  San Pedro.  TYPE SPECIMENS:  Holotype:  UC 205622; collected Sept., 1908. Isotypes:  UC 40287, AHFH 58852, 60403, US 57107, UW 64239. REFERENCES: Setchell and Gardner, 1920a, p. 285~6, Plate 26, Fig. 1. Setchell and Gardner, 1920b, p. 272-3, Plate 21, Fig. 1. ?Dawson, 1944, p. 201. Dawson, 1945, p. 23. Dawson, 1946b, p. 170. Dawson, 1947, p. 9. Doty, 1947, p. 9.. Dawson, 1954, p. 101. ?Chapman, 1956, p. 395, Fig. 391. ?Dawson, 1959b, p. 6,11. Papenfuss, 1960, p. 308. Dawson, 1961, p. 374. Abbott and Hollenberg, 1976, p. 80, Fig. 37. PROBABLE SYNONYMS Ulva brevistipita Chapman, 1956. TYPE LOCALITY: Midlittoral pool, Titahi Bay, New Zealand. TYPE SPECIMENS:  Holotype:  CANTY (Laing H. 4321); no collection date.  229 REFERENCES: Chapman, 1956, p. 387, Fig. 30d. Ulva costata (Howe) Hollenberg, TYPE LOCALITY:  Surf-washed rocks, Chincha Islands, Peru.  TYPE SPECIMENS: Lectotype: 1907.  1971.  NY (Coker no. 193); collected June 18,  Syntypes: NY, UC 197872.  REFERENCES: Howe, 1914, p. 20-2, Plate 1, Plate 2, Fig. 10-23  (as U.  fasciata  f. costata Howe). Taylor, 1947, p. 60 (as U. fasciata f. costata). Dawson, Acleto and Foldvik, 1964, p. 8-9, Plate 3 (as U. fasciata f. costata). Hollenberg, 1971, p. 283, Fig. 1. Abbott and Hollenberg, 1976, p. 80, Fig. 36. DISTRIBUTION: N.E. Pacific:  Vancouver Island, British Columbia to southern Baja  California, Mexico. S.E. Pacific:  Peru (as U. fasciata f. costata)?  S.W.  New Zealand.  Pacific:  REPRESENTATIVE SPECIMENS: BRITISH COLUMBIA: Port Harvey, E. Crancroft Island (50°33.5'N, 126°16.0'W), ll-IX-70, UBC 48805; Middle Point, Duncan Bay, Vancouver I s i . (50°05.3'N, 125°18.2'W), 10-IX-70, UBC 48803; I s i . S.E. of Grassy I s i . , Kyuquot S., Vancouver I s i . (49°55.4'N, 127°15.0'W), 14-V-75, UBC 56998; Miracle Beach, Vancouver I s i . (49°51'N, 125°5'W), 16-IIX-59,  UBC  230  11445; E. side of Diana I s l . , Barkley S. (48°50.03'N, 125°11.11W), 25VII-75, UBC 58007 (U253); Brady's Beach, Barkley S., Vancouver I s l . (48°49.74'N, 125°09'w), 13-X-73, UBC 56999, 15-XI-74 57969 (Ul43a); Cable Beach, Barkley Sound (48°49.46'N, 125°09.4'W), 15-11-76, UBC 57976 (U268); Second Beach, Bamfield, Barkley S. (48°48.85'N, 125°09.7W), 10-VII-75, UBC 57975 (U246). OREGON: North Jetty, Yaquina Bay (approx. 44°39'N, 124°.002W), 6-1-66, OSU 25; Seal Rocks (44°29.5'N, 124°06.3'W), 10-VI-66, UBC 24958; Cape Perpetua (approx. 44°17'N, 124°07'W), 10-VII-68, OSU .1422; Fossil Point, Coos Bay (approx. 43°21'N, 124°21'W), 8-IIX-48, HP 2429. CALIFORNIA: Dillons Beach, Tomales Bay (approx. 38°14'N,122°55'W), XI-15, UC 205625; Duxbury Reef, Bolinas (38°54'N, 122°42'W), IV-1896, UC 98494; Pescadero (37°15'N, 122°25'W), 7-XI-1891, DS 304423; Santa Cruz (36°58'N, 122°01'W), no date, US 54924; North Jetty, Moss Landing (approx. 36°48'N, 121°47'W), 14-VII-72, MLML 1104; Monterey (approx. 36°48'N, 122°01W), ll-VII-01, UC 98493; Carmel Beach (approx 36°33'N, 121°55.9'W), 22-VII-39, GMS 7754; E. side of Loon Point, Santa Barbara Co. (approx. 34°25'N, 119°34'W), 19-XII-57, AHFH 67481; Carpinteria (34°23.5'N, 119°31.5*W), 26-IX-57; Ventura (34°16.7'N, 119°17'W), 28-VI-57, AHFH 66014; W. Malibu (approx. 34°03'N, 118°57'W), IX-08, UC 305622; S. of Point Fermin, San Pedro (33°42.35'N, 118°17.10' W), 24-VIII-77, UBC 58040, (U339);San Nicolas I s l . (33°15'N, 119°30'W), 13-111-32, UC 633413; La Jolla (approx. 32°51'N, 117°10'W), l-VII-46, US 38995; Coronado (approx. 32°42'N, 117°12*W), VIII-03, US 34586. BAJA CALIFORNIA: Punta Descanso (approx. 32°16'N), 30-XI-63, AHFH 78432, 8-IV-45, UC  231  694036; Bahia de Todos Santos, Ensenada (approx. 31°48*N, 116°42'W), 29-X-51, US 41727, VII-24, UC 395360; Rio San Telmo Reef (approx. 30°57'N, 116°15'W), 12-111-45, UC 693937; near Punta Maria (28°55'N, 114°32'W), 14-IV-46, US 39015; Isla Cedros (approx. 28°12 N, 115°15'W), ,  19-IV-51, UC 940035; Bahia Tortuga (approx. 27°39'N, 114°51*W), 26-VII57; Punta Abreojos (approx. 26°42'N, 113°30'W), 30-IV-50, AHFH 54523; San Roque (approx. 25°36'N, 100°09'W), VTl-1899, UC 98506. PERU: Playas de Barranco, 18-IX-48, M 61522; Pucusans, 9-IV-63, AHFH 75447; Chincha Islands (approx. 11.27'S, 79.05'W), 18-VI-07, NY (Coker no. 193), UC 197872. NEW ZEALAND: Eastbourne, Port Nicholoson (approx. 41°17'S, 174°54'E), 17-VIII-58, UW 244317; Lyall Bay (approx. 41°19'S, 174°48'E), 06-V-?, VJC 1137; The Bluff, Ninety Mile Beach (approx. 34°41'S, 172°55'E), 16-1-41, AKU 010002; Titahi Bay (approx. 41°06'S, 174°50'E), no date, CANTY (Laing H. 4321); St. Clair, 13-1-33, CANTY (Laing Herb. 4322).  232 8.  Chloropelta caespitosa gen, et sp. nov. ined. TYPE LOCALITY: Forming densely tufted mats on boulders, cement blocks and kelp stipes i n the upper intertidal zone, Point Fermin, San Pedro. TYPE MATERIAL: Holotype: UBC 57963; collected May 26, 1976. Isotypes:  UBC 57965, 1101 \  DISTRIBUTION N.E. Pacific:  Los Angeles to Pacific Beach, California.  REPRESENTATIVE SPECIMENS: Sunset Blvd., Los Angeles (34°02.2'N, 118°34.45'W), 15-XI-56, AHFH 63176; Point Fermin, San Pedro (33°42.35'N, 118°17.10'w), 26-V-76; UBC 57963, 57965, 1108 (U286), 24-VTII-77, UBC 57964 (U338); Laguna 1  Beach (33°32'N, 117°46'W), 26-V-76, UBC 57967, 57968 (U290); Bird Rock, La Jolla (32°48.9'N, 117°16.4'W), 25-11-57, AHFH 64802; Tourmaline Surfer Park, Pacific Beach (32°48.1'N, 117°15.6'w), 27-V-76, UBC 57966. Chloropelta Thallus at maturity a membranous peltate distromatic blade attached by a central rhizoidal disk; quadriflagellated and biflagellated reproductive swarmers produced i n cells along the blade margins; reproductive cells germinate into uniseriate filaments that later develop into multiseriate germlings by repeated longitudinal divisions perpendicular to the surface of the f i l a ment; separation of the cells along the longitudinal axis lead to the development of a clavate monostromatic saccate germling; a division of each c e l l of the monostromatic c e l l layer "in a plane parallel to the germling surface produces a distromatic saccate germling; degeneration of the apical end produces preserved i n 70% alcohol.  233 at f i r s t a campanulate thallus; continued growth of the thallus results i n a flattened peltate blade. Chloropelta  caespitosa  Thalli orbicular or ovate, peltate or split to the base; planular or ruffled along the margins; forming dense tufts or tufted turfs; plants from a few mm to 60 mm;or more i n diameter; cells i n surface view angular, irregular, randomly arranged, between 4 and 29 ym across; rhizoidal cells near attachment disk loosely arranged; blade from 17 ym thick at the margins to 95 ym or more near the base, mostly around 30-35 ym thick; cells i n sectional view nearly isodiametric, usually wider than t a l l near the margin and taller than wide near the center; 1-2 or rarely 3 pyrenoids i n the single parietal chloroplast of each c e l l ; grass green i n color.  VTI.  SUMMARY Results of studies on the taxonomy and morphological variation of  distromatic ulvaceous algae from the northeast Pacific are summarized below: 1.  Six species of Ulva (U. califomica, U. fasciata, U. fenestrata, U. rigida, U. stenophylla, U. taeniata) are recognized for the northeast Pacific using morphological, developmental and anatomical criteria.  One  of these species, U. fasciata, was not previously recognized for this area.  The validity of a seventh species, U. conglobata, remains unclear.  Six of the previously recognized taxa (U. angusta, U. costata, U. dactyl i f e r a , U. expansa, U. fasciata f. lobata, U. scagelii) are reduced to synonyms of other species, and another species, U. lactuca, i s thought not to occur on this coast. 2.  Some morphological and anatomical characteristics previously used to separate species were found to vary with environmental factors. a.  Development and morphology in Ulva califomica varied with temperature.  This has resulted i n the previous placement of northern  specimens into U. scagelii (Chihara, 1968). b.  In U. taeniata the number and length of teeth decrease and the blade thickness increases with an increase of water temperature.  Non-  dentate specimens south of Point Conception were previously identified as U. angusta, U. costata or U. dactylifera.  In Barkley Sound  U_. taeniata showed considerable seasonal variation i n size and morphology. c.  Size, shape and thickness of t h a l l i i n U. fenestrata varied with vertical position, wave exposure and time of year.  The range i n  morphology and anatomy of this species included the criteria pre-  235  viously used to delimit U. expansa and U. lobata. 3.  An unusual form of reproduction was observed for Ulva fasciata from Hawaii similar to that reported for U. lactuca by Bonneau (1978). Aplanospores developed into a floating multicellular stage that eventually released biflagellated swarmers. The globose stage, i f produced in nature, would greatly increase the species'potential for dispersal.  4.  A new genus and species of distromatic ulvaceous algae were described from the northeast Pacific. closely resembles Ulva.  Chloropelta caespitosa, when mature,  However, the developmental pattern is dis-  tinctly different and places this alga closer to Ulvaria.  236 LITERATURE CITED Abbott, I, A. &G..J. Hollenberg. 1976. Marine Algae of California. Stanford University Press, Stanford, Calif, xii+827 pp. Agardh, C. A.  1822.  Species algarum... 1(2): 169-531. Lund.  Agardh, C. A.  1824.  Systema algarum. xxxviii+312 pp.  Agardh, C. A.  1828.  Species algarum... 2(1): 1-189. Greifswald.  Lund.  Agardh, J. G. 1883. T i l l algernes systematik,nya bidrag, Afd. 3. Lunds Univ. S r s s k r . 19: 1-177. Anderson, C. L. 217-225.  1891.  List of California algae, with notes.  Zoe 2:  Arasaki, S. & I. Shihira. 1959. Variability of morphological structure and mode.of reproduction i n Enteromorpha linza. Jap. J. Bot. 17: 92-100.- . Ardre, F. 1967. Une Ulva a thalle remarquable des cotes du Portugal. Rev. Algol., n.s. 8: 292-297. Baudrimont, R. 1961. Influence de divers milieux de culture sur le developpement de quelques Ulvacees. Botaniste 44: 77-192. Biebl, R. 1972. Studien sur tempuraturresistenz der Gezeitenalge Ulva pertusa Kjellmann. Bot. Mar. 15: 139-43. Blackman, F. F. & A. G. Tansley. 1902. A revision of the classification of the green algae. New Phytol. 1: 17-24, 47-8, 67-72, 89~96, 114-120, 133-44, 163-8, 189-92, 213-20, 238-44. Bliding, C. 1938. Studien liber Entwicklung and Systematik i n der Gattung Enteromorpha. I. Bot. Not. 1938: 83~90. Lund. Bliding, C. 1963. A c r i t i c a l survey of European taxa i n Ulvales, Part I. Capsosiphon, Percursaria, Blidingia, Enteromorpha. Bot. Not. Suppl. 8: 1-160. Bliding, C. 1968. A c r i t i c a l survey of European taxa in Ulvales, Part II. Ulva, Ulvarian, Monostroma, Kornmannia. Bot. Not. 121: 534-629. Bold, H. C. & M. J. Wynne. 1978. Introduction to the Algae. PrenticeHall, Inc., Englewood C l i f f s , New Jersey. 706 pp. Bonneau, E. R. 1977. Polymorphic behavior of Ulva lactuca (Chlorophyta) i n axenic culture. I. Occurence of Enteromorpha-like plants i n haploid clones. J. Phycol. 13: 133-140. Bonneau, E. R. 1978.. Asexual .reproduction capabilities i n Ulva lactuca L. (Chlorophyceae). Bot. Mar. 21: 117-1212. Bryhni, E.  1974.  Genetic control of morphogenesis i n the multicellular  237 alga Ulva mutabilis - defect i n c e l l wall production.  37: rmiw.  Develop. Biol.  .  Buffaloe, N; D. 1958. A comparative cytological study of four species of Chlamydomonas. Bull. Torrey Bot. Club 85: 157-78. Burrows, E. M. .1959. Growth form and environment i n Enteromorpha. Soc. (Bot.) 26: 204-6.  J. Linn.  Canadian Hydrographic Service. 1974. Canadian Tide and Current Tables for 1975. Vols. 5 &6. Marine Sciences Directorate, Dept. of the Environment, Ottawa. Carter, N. 1926. An investigation into the cytology and biology of the Ulvaceae. Ann. 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