yi PREFACE 



the general content of the science. Its use is not dependent, 

 however, upon any particular sequence of topics, for the 

 material is presented in the form of semi-independent essays 

 intended to be separately understandable. Obviously there 

 is far mope in the book than can be touched in a year in the 

 laboratory, but every topic thus studied should form a leaven 

 of objective understanding for many contiguous subjects. 

 From the abounding wealth of material it has been difficult 

 to select, and it is not supposable that the choice will please 

 everybody, any more than will all the particulars of the 

 treatment. Perhaps, however, the various objections will 

 to some extent counterbalance one another. At all events, 

 I have tried to present systematically and in good proportion 

 the salient and essential matters in our scientific knowledge 

 of plants. 



The illustrations are taken from many sources, which are 

 acknowledged with the cuts in all cases except where they 

 are new. It is surely as legitimate to use a good published 

 picture as a good published idea, of course with due credit, 

 and, moreover, its use seems a deserved tribute to its ex- 

 cellence such as its author would desire. Many are taken 

 from the well-known works of Sachs, Goebel, Kerner, Gray, 

 and Strasburger, and are so good that better can hardly be 

 made ; and we should not deprive the student of their use, 

 or waste labor in providing inferior new ones, only because 

 the frequency of their appearance has made them wearisome 

 to us. Messrs. Henry Holt and Company have given me 

 full permission to use pictures from Kerner's work, as well 

 as two from Sargent's Plants and their Uses, and several 

 from my own book The Living Plant, published by them. 

 Also I have used many, by permission, from publications of 

 The Macmillan Company, and especially from one of the 

 greatest of botanical publications, the Cyclopedia of American 

 Horticulture, edited by Professor L. H. Bailey, who has 

 graciously granted me the privilege of drawing at will from 

 that work. The Bausch & Lomb Optical Company have 



