Xll PREFACE 



Chapters X, Geographical Distribution, and XIII, 

 The Great Groups of Plants, and the Bibliography are 

 new. No attempt has been made to cite the voluminous 

 periodical literature in the Bibliography, but needless to 

 state, this has been freely consulted and drawn upon. 

 Numerous citations are given as foot-notes, especially in 

 Chapter X. 



In going over the chapters it also became evident that 

 since, in order to read them understandingly, one must 

 have a clear conception of the facts of the lift history of a 

 vascular plant, it would be best to introduce from the 

 Fundamentals of Botany the three chapters (viz. XII- 

 XIV) on the life history of the fern. As stated in the 

 Preface to that book, while the ultimate problem of botany 

 is the development of the kingdom of plants, the more 

 immediate and fundamental problem is the development 

 of the individual plant. "Ontogeny is fundamental 

 because without a knowledge of its processes the processes 

 of phylogeny cannot be comprehended. Phylogeny is 

 the ultimate problem because its complete solution in- 

 volves an orderly description of all the phenomena of 

 plant life, and their relation to each other." 



The author is specially indebted to Dr. O. E. White, 

 curator of plant breeding in the Brooklyn Botanic Garden, 

 for a careful reading of the entire manuscript and for 

 many valuable suggestions; also to Mr. Norman Taylor, 

 curator of plants, in connection with Chapter X, and 

 to Dr. Alfred Gundersen, associate curator of plants in 

 the same institution, for numerous constructive criticisms 

 in connection with Chapter XIII. The diagram show- 

 ing the apparent affinities and approximate geological 

 distribution of the main groups of vascular plants (p. 



