iv PREFACE 



eluded the essential foundation for most of the varied work that is 

 included to-day under botany. 



We recognize that the presentation of the three great subjects here 

 included is very compact, but the book is not intended for reading 

 and recitation. The teacher is expected to use it for suggestive 

 material and for its organization ; the student is expected to use it 

 in relating his observations to one another and to the general points 

 of view that the book seeks to develop. There is a continuity of 

 presentation in each part, so that random selection may miss the 

 largest meaning. For example, in the part on morphology, the thread 

 upon which the facts are strung is the evolution of the plant kingdom, 

 and each plant introduced has its peculiar application in illustrating 

 some phase of this evolution. When certain groups are selected for 

 laboratory study, therefore, the intervening text should be read. 



It is important to call attention to the fact that the book has been 

 prepared for the use of undergraduate students. It does not repre- 

 sent our conception of graduate work, which should include much 

 that is omitted here. For example, the graduate student should 

 be introduced to the original sources of information, which would 

 involve an extensive citation of literature far beyond the needs of the 

 undergraduate. Still less has this book been written for our profes- 

 sional colleagues, who will notice what they may regard as glaring 

 omissions. Such omissions must be taken to express a deliberate 

 judgment as to what may be omitted with the least damage to the 

 undergraduate student. The motive is to develop certain general 

 conceptions that are felt to be fundamental, rather than to present 

 an encyclopedic collection of facts. This purpose has demanded 

 occasionally also a greater apparent rigidity of form in general state- 

 ments than is absolutely consistent with all the facts ; but it was a 

 choice between a clear and important conception for one with no 

 perspective and a contradiction of large truths by isolated facts, result- 

 ing in confusion. For the same reasons, the extensive terminology 

 of the subject has been kept in the background as much as possible. 

 Definitions usually are made an incident to the necessary introduc- 

 tion of terms. It is assumed that in so far as the definite application 

 of a term may not seem clear, the student will find a compact defini- 

 tion in the current dictionaries. 



