PREFACE vii 



Chapter IX., in which the now prominent family of 

 the Botryopterideae is described, has been largely 

 extended. 



Chapters X.-XIV. have required an even more 

 drastic revision, and are, to a great extent, new. 



Chapters X. and XL, which deal with the Fern-like 

 Spermophyta (the new class Pteridospermeae) are now 

 written from a fresh point of view, for it is only since 

 the appearance of the first edition that we have become 

 acquainted with the true nature of this extensive group, 

 as shown by its advanced methods of reproduction. 



In Chapter XII., now headed "The Cordaitales," 

 the section on the family Pityeae is altogether new, 

 and that on the Poroxyleae considerably extended. 

 Our ideas of the relationships of the groups concerned 

 have advanced greatly, though, as regards the family 

 Cordaiteae, our knowledge still rests essentially on the 

 work of Renault and Grand'Eury. 



The Mesozoic Gymnosperms (Chapter XIII.) now 

 appear in quite a new light, owing to the brilliant 

 elucidation of the flowers of the American fossil 

 Cycadophyta by Dr. Wieland, whose work at last 

 brings the great question of the origin of Angiosperms 

 within the range of scientific discussion. 



Lastly, the concluding chapter has necessarily under- 

 gone a complete transformation, in order to bring it 

 into harmony with the results of so much new research 

 of fundamental importance. In this chapter a 



