GREEN PLANTS
Their Origin
and Diversity
Peter R. Bell, M.A.
Emeritus Professor of Botany in
the University of London
CAMBRIDGE
UNIVERSITY PRESS
CONTENTS
PREFACE
9
1. GENERAL FEATURES OF THE PLANT KINGDOM
Characteristics of the Living State
Autotrophic and Heterotrophic Nutrition
The Structure of the Phototrophic Cell
Evolutionary Consequences of Photosynthesis
The Mobility of Plants
Life Cycles
Life Cycles of Transmigrant Forms
Sexual Reproduction in Later Terrestrial Vegetation
Classification of the Chlorophyllous Phototrophs
11
11
11
12
15
18
18
20
20
21
2. THE SUBKINGDOM ALGAE—Part 1
Biological Features of Algae
General Classification of the Algae
Algae Containing Chlorophyll a
Prokaryotic Forms
Cyanophyta
Eukaryotic Forms
Rhodophyta
23
23
25
25
25
25
32
32
3. THE SUBKINGDOM ALGAE—Part 2
Algae Containing Chlorophylls a and b
Prokaryotic Forms
Prochlorophyta
Eukaryotic Forms
Chlorachniophyta
Chlorophyta
Euglenophyta
4. THE SUBKINGDOM ALGAE—Part 3
Algae Containing Chlorophylls a and c .
Chrysophyta
Xanthophyta
Haptophyta (Prymnesiophyta)
Dinophyta (Pyrrophyta)
Bacillariophyta
Cryptophyta
Phaeophyta
Evolutionary Trends Within the Algae
Aquatic Habitat and Evolutionary Change
The Antiquity of the Algae
Evolution of the Vegetative Thallus
Evolution of Sexual Reproduction
.v
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38
38
38
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39
39
70
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74
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76
79
80
82
86
87
96
96
96
97
98
6
Contents
Life Cycles of Algae
The Importance of the Algae in the Evolution of Plants
5. THE SUBKINGDOM BRYOPHYTA (Mosses and Liverworts]
General Features of the Bryophytes
Bryophyta
Hepaticae (Liverworts]
Anthocerotae (Hornworts]
Musci (Mosses]
Relationships of the Bryophyta
Origin of the Bryophytes
Evolutionary Relationships Within the Bryophytes
98
99
100
100
100
102
113
115
125
125
127
6. THE SUBKINGDOM TRACHEOPHYTA—Part 1
129
General Features of the Tracheophytes
129
Tracheophyta
129
Spore-Bearing Tracheophytes Known Only as Fossils
131
Rhyniophyta
131
Zosterophyllophyta
133
Trimerophyta
134
Spore-Bearing Tracheophytes With Living Representatives: The Fern Allies . 135
Psilopsidophyta
135
Lycophyta
140
Sphenophyta
157
7. THE SUBKINGDOM TRACHEOPHYTA—Part 2
Spore-Bearing Tracheophytes With Living Representatives: The Ferns
Filicophyta
The Ophioglossales
The Marattiales
The Filicales
The Hydropteridales
Precursors of the Ferns
The Origin of the Filicophyta and the Morphological Nature of
the Megaphyll
167
167
167
167
171
175
190
192
8. THE SUBKINGDOM TRACHEOPHYTA—Part 3
Primitive Ovulate Plants and Their Precursors
Progymnospermophyta
Gymnospermophyta
The Lyginopteridales
The Cycadales
The Bennettitales
The Caytoniales
The Cordaitales
The Coniferales and Taxales
The Ginkgoales
The Gnetales
Gymnospermy as an Evolutionary Grade
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215
227
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237
9. THE SUBKINGDOM TRACHEOPHYTA—Part 4
The Flowering Plants
Angiospermophyta
Growth Forms of Angiosperms
238
238
238
238
196
Contents
Growth and Anatomy of Stems
Leaves
Roots
Correlation Within the Plant Body
Reproduction
Evolutionary Aspects of Angiosperms
The Emergence of the Angiosperms
Evolution of Morphological Features Within the Angiosperms
Recent Evolution Within Families and Genera
The Main Trends of Evolution in the Angiosperms
7
242
246
251
254
255
272
272
277
282
283
GLOSSARY
285
SUGGESTIONS FOR FURTHER READING
299
INDEX
303