PREFACE 



IN the present volume I have endeavored to present 

 in as untechnical a manner as seemed feasible the 

 more striking facts bearing upon the evolution of plant 

 forms. While there are numerous excellent text-books 

 in which most of the statements here given are clearly 

 presented, there is none, at least in English, so far as I 

 am aware, where a connected account of the develop- 

 ment of the plant kingdom from an evolutionary stand- 

 point has been attempted. Of course every modern 

 system of classification is based upon the assumption of 

 a genetic connection between the different groups, and 

 must take into account the origin of plant forms ; but 

 these phylogenetic problems are necessarily subordi- 

 nated in the general text-books. Moreover, these text- 

 books are, for the most part, avowedly prepared for 

 the use of botanical students alone. 



It seemed to the writer that an accurate, if some- 

 what general, and not strictly technical, statement of 

 our present knowledge concerning the data from which 

 the genealogical history of the vegetable kingdom may 

 be traced, might be of interest not only to such bota- 

 nists as have not concerned themselves specially with 

 this phase of the science, but also to zoologists, and 

 those general readers who are interested in biological 

 problems. 



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