PALEOBOTANY: A SKETCH OF THE ORIGIN 

 AND EVOLUTION OF FLORAS. 



By Prof. Edward W. Beeky, 



The Johns Hopkins University. 



[With 6 plates.] 

 CONTENTS. 



Page. 



Introduction 2S9 



Methods of preservation 292 



General principles 294 



Relation to other sciences 297 



Types of vegetation : 



Thallophyta 298 



Bryophyta 300 



Pteridophyta 301 



Arthrophyta 311 



Lepidophyta 322 



Pteridosphermophyta 334 



Cycadophyta 340 



Coniferophyta 3f>2., 



Angiospermophyta - 307 



The evolution of floras : 



Stages of evolution 372 



Pre-Devonian plants 377 



Devonian floras 378 



Carboniferous and Permian Cosmopolitan floras*. 381 



The Glossopteris-Gangamopteris flora 383 



Triassic floras 386 



Jurassic floras 392 



Lower Cretaceous floras 394 



Upper Cretaceous floras 398 



Tertiary floras 401 



Pleistocene floras 406 



INTRODUCTION. 



The study of the former plant life of the globe possesses a many- 

 sided fascination, not the least of which is the light which it 

 sheds upon physical history. The term paleobotany, applied to the 

 science of fossil plants, has come to be widely adopted of late years. 

 Its story is not merely the history of the endless succession of plants 

 which have inhabited the earth since life first came into existence, 

 but it aims to understand and interpret these in terms of the evolu- 



289 



