PREFACE 



The point of view and the methods of study first advanced in 

 "Research ^lethods in Ecoloo-y" have proved so satisfactor\- in 

 teaching as to make it desirable to embody them in a text-book. 

 The present text has been based largely upon ''Research Methods," 

 though most of the matter is new or rewritten. The manner of 

 treatment is essentially the same, but the subject-matter has been 

 rearranged and broken up into a larger number of chapters. The 

 plant is first considered as an individual, with respect to factor, 

 function, and form, and then as a member of a plant group or 

 formation. 



The reasons for regarding ecology and physiolog}- as essentially 

 the same have been given elsewhere, and need not be rej)eatcd 

 here. An endeavor has been made to give the various parts of this 

 vast field their proper importance. Since ecolog\^ and physiolog\' 

 are merged, it is manifestly impossible to give to either what would 

 be regarded as a complete treatment by a specialist in either lino. 

 No attempt has been made to touch all the points in each, but it is 

 thought that nothing really fundamental has l)een omitted. 



The book is intended for use with classes in second-year botany 

 in college and university. In manuscript form, it has Ix^cn in such 

 use for two years with good results. Although the amount of 

 laboratorj^ and field work is large, it is possible to accomplish :ill of 

 it in a course requiring 6-8 hours of laboratory time each week. 

 This can be done only by careful planning on the ]>art of both in- 

 structor and student, and for this reason the following suggestions 

 are offered as aids. 



The instnictor will find it imperative to ]ilan in advance* for the 

 experiments for the whole year, in order that plants may lx> ivady 

 as needed. Seeds and fruits for the study of migration should 1)0 

 collected in the fall. Shade tents, water-content series, and com- 



iii 



