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. 
