PREFACE. 



THE present book is the result of a revision and elaboration 

 of the author's " Elementary Botany," New York, 1898. The 

 general plan of the parts on physiology and general morphology 

 remains unchanged. A number of the chapters in the physio- 

 logical part are practically untouched, while others are thoroughly 

 revised and considerable new matter is added, especially on the 

 subjects of nutrition and digestion. The principal chapters 

 on general morphology are unchanged or only slightly modified, 

 the greatest change being in a revision of the subject of the 

 morphology of fertilization in the gymnosperms and angiosperms 

 in order to bring this subject abreast of the discoveries of the 

 past few years. One of the greatest modifications has been in 

 the addition of chapters on the classification of the algae and 

 fungi with studies of additional examples for the benefit of those 

 schools where the time allowed for the first year's course makes 

 desirable the examination of a broader range of representative 

 plants. The classification is also carried out with greater definite- 

 ness, so that the regular sequence of classes, orders, and families 

 is given at the close of each of the subkingdoms. Thus all the 

 classes, all the orders (except a few in the algae), and many of 

 the families, are given for the algae, fungi, mosses, liverworts, 

 pteridophytes, gymnosperms, and angiosperms. 



But by far the greatest improvement has been in the complete 

 reorganization, rewriting, and elaboration of the part dealing 

 with ecology, which has been made possible by studies of the 

 past few years, so that the subject can be presented in a more 

 logical and coherent form. As a result the subject-matter of 



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