THE STRUCTURE AND REPRODUCTION OF THE ALGAE FRONTISPIECE : Draparnaldiopsis indica Bharadwaja (photo: Prof. Y. Bharadwaia) THE STRUCTURE AND REPRODUCTION OF THE ALGAE VOLUME I Introduction, Chlorophyceae, Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenineae, Colourless Flagellata BY F. E. FRITSCH, D.Sc, F.k.o. Professor of Botany in the Uni'versity of London, Queen Mary College so-v CAMBRIDGE LT THE UNIVERSITY PRESS 1948 First printed in Great Britain at the University Press, Cambridge Reprinted by litho-offset by Jarrold & Sons Ltd and published by the Cambridge University Press (Cambridge, and Bentley House, London) Agents for U.S.A., Canada, and India: Macmillan CONTENTS Draparnaldiopsis indica Bharadwaja . . . Frontispiece PREFACE TO VOLUME I . . . • . . page xv iNTRODUCTIOfJ . . . . .. Algae and Flagellata . . . .. The Broad Classification of the Algae 4 The Range of Structure among the Algae 12 {d) The Motile Type . . .. 12 {b) Palmelloid and Dendroid Types . 15 (c) The Coc.coid Habit . . .. 16 (d) The Origin and Characteristics of the Fila mentous Habit . . .. 17 (e) The Heterotrichous Habit . 20 (/) The Siphoneous Habit 21 {g) The Advanced Types of Algal Construction 21 Qi) Epiphytes, Endophytes, Parasites . 24 (j) Parallelism. 27 The Special Structural Features of the Algal Cell 28 Nucleus . 28 Centrosomes 29 Flagella . 31 Eye-spot (stigma) 33 Contractile vacuoles 35 Mitochondria (Chondriosomes) 37 The General Course of Reproduction in the Algae 38 Vegetative Reproduction . 38 .Asexual Reproduction 39 Sexual Reproduction. 43 The Life-cycle of the Algae 51 Literature relevant to the Iritroduction 54 VI CONTENTS CLASS I. CHLOROPHYCEAE (ISOKONTAE) page 60 The Cell-wall . . ' 61 The Protoplast . . , 62 Chloroplasts and Pyrenoids . . • . ,' . 63 The Nucleus 69 Reproduction . . . . . .. 72 Classification and Status of the Chlorophyceae . . 73 Literature relating to the Introductory Discussion of the Chlorophyceae . • • • 75 ORDER L VOLVOCALES . . . . . 77 (a) The Motile Forms (Suborder Chlamydomonadi- neae) . . . . .. 78 Unicellular Forms . . .. 78. Chlamydomonadaceae 78 Sphaerellaceae. 83 Polyblepharidaceae . . . , 8S Phacotaceae . . . .. 88 Colourless Unicellular Types 90 Asexual Reproduction among the Unicellular Chlamydomonadineae . .. 91 Palmelloid and other Sedentary Phases . 94 The Colonial Forms . . .. 95 Asexual Reproduction of the Colonial Forms 106 Sexual Reproduction of the Chlamydomonadi neae 109 The Further Development of the Zygote 116 (b) The Palmelloid Forms (Suborder Tetrasporineae) 121 • The Family Tetrasporaceae . . .. 122 The Family Palmellaceae . . .. 125 Reproduction of the Tetrasporineae 129 The Dendroid Forms (Suborder Chlorodendri- (c) neae) . . ; " ' . . .. 130 Classification of the Volvocales . _ . 136 Literature of Yolvocales . . . .. 137 CONTENTS Vll ORDER II. CHLOROCOCCALES . . . ., page 145 Chlorococciim and Chlorella . . . . . 1 45 The Unicellular Chlorococcales . 147 The Endophytic Habit among Chlorococcales 154 The Colonial Chlorococcales . . .. 159 Chlorellaceae . . . .. 159 Oocystaceae . . . .. 159 Selenastraceae . .. .. . . 162 Dictyosphaeriaceae . . .. 163 The Family Hydrodictyaceae 166 The Family Coelastraceae ' . 174 The Affinities and Classification of the Chlorococcale 5 178 The Ecology and Physiology of the Chlorococcales 180 The Family Chlorosphaeraceae 190 Literature of Chlorococcales . 191 ORDER III. ULOTRICHALES 198 The Suborder Ulotrichineae . 199 (a) The Filamentous Types 199 Microspora . .. 208 Cylindrocapsa . . . 210 (b) The Thalloid Types (Ulvaceae) 212 The Suborder Prasiolineae 217 The Suborder Sphaeropleineae 220 The Classification of Ulotrichales . 226 Literature of Ulotrichales 226 ORDER IV. CLADOPHORALES 229 Vegetative Structure 231 The Aegagropilous Cladophoraceae • 237 Reproduction . . .. 239 The Affinities of the Cladophoraceae 242 The genus Wittrockiella 243 The genus Arnoldiella . 245 Literature of Cladophorales . 246 vni CONTENTS ORDER V. CHAETOPHORALES page 248 (a) The Family Chaetophora'ceae . . 2 49 The Chaetophoreae • 249 Reproduction of the Chaetophorea ' • - 2 55 Prostrate Types (Prostratae). • 258 The SpeciaHsed Erect Types (Erec tae) . .^ 262 Reproduction of the Specialised C haetophora- ceae . . 264 (b) The Family Trentepohliaceae . : 266 The Gongrosireae . 1266 The Gomontieae . . . . . .. 270 The Trentepohlieae • 273 (c) The Family Coleochaetaceae . 281 (d) The Family Chaetosphaeridiaceae . 286 (e) The genus Pleurococcus . 289 The Status of the Chaetophorales . 290 Literature of Chaetophorales . 291 ORDER VI. OEDOGONIALES 296 Vegetative Structure 296 Vegetative and Asexual Reproduction 301 Sexual Reproduction . * . • 303 The Status of the Oedogoniales • 308 Literature of Oedogoniales • 309 ORDER VIL CONJUGALES . 310 Suborder L EUCONJUGATAE . • 3" {a) The MesOtaenioideae (Saccoderm Desmids) . 311 {b\ The Zygnemoideae ' ' • - 3 16 Vegetative Structure 316 Fragmentation of the Threads 320 The Process of Conjugation 322 {a) Zygnemaceae . • 323 {b) Mougeotiaceae • 329 Germination of the Zygospores • _ • - 3 33 The Classification of the Zygner noideae . 336 CONTENTS IX Suborder II. DESMIDIOIDEAE (PLACODERM DESMIDS) page 337 Structure of the Cell. . . . , , 338 'Cell-division . . . . . .. 345 The Process of Conjugation . . .. 348 The Evolutionary Sequence in Desmids 353 Occurrence and Distribution of Desmids 360 Interrelationships and Affinities of the. Conjugales 361 Literature of Conjugales , . . .. 362 ORDER VIII. SIPHONALES . . .. • 368 {a) The Family Protosiphonaceae . 370 {b) • The Fs(mily Caulerpaceae- 374 Bryopsis . . . . . .. 375 Caulerpa . . . . .. 377 (c) The Family Derbesiaceae 385 (d) The Family Dasycladaceae 387 The Acetabularieae . . .. 393 The t"ossil Dasycladaceae 397 The Reproduction of the Dasycladaceae 401 (e) The Family Codiaceae . . .. 402 Vegetative Structure . . .. 402 The Reproduction of the Codiaceae 41 r (/) The Family Valoniaceae . . .. 413 Vegetative Structure . . .. 413 • The Reproduction of the Valoniaceae -. 424 (g) The Family Chaetosiphonaceae • 425 (h) The Family Phyllosiphonaceae . 426 (i) The Family Vaucheriaceae . 428 Vegetative Structure . . .. . 428 Asexual Reproduction . • 431 Sexual. Reproduction . . .. • 435 The Affinities of the Vaucheriaceae • 438 Taxonomy . . . . . .. • 439 Literature of Siphonales • 440 X CONTENTS ORDER IX. CHARALES page 447 Vegetative Structure 447 Cell-structure 453 Sexual Reproduction 455 Embryology 461 Vegetative Reproduction 463 The Position of the Charales among the Algae 465 Literature of Charales . . .. 466 CLASS IL XANTIIOPHYCEAE (HETERO- KONTAE) 470 ORDER I. HETEROCHLORWALES . . 470 (a) The Motile Unicellular Forms (Heterochlorineae) 470 (b) The Palmelloid Forms (Heterocapsineae) . 474 (c) The Dendroid Forms (Heterodendrineae) . 478 (d) The Rhizopodial Forms (Heterorhizidineae) 480 ORDER IL HETEROCOCCALES . . .. 481 The Zoosporic Forms . . . .. 481 The Azoosporic Unattached Forms 484 The Epiphytic Heterococcales 486 ORDER III. HBTEROTRICHALES . 491 ORDER IV. HETEROSIPHONALES^ . . .. 495 Amoeboid and Heterotrophic Types among the Xanthophyceae . . . .. 499 The Status and Relationships of the Xanthophyceae 501 Literature of Xanthophyceae . .. 503 CLASS III. CHRYSOPHYCEAE . 507 The General Characteristics of the Class . 508