BESEAECH METHODS IX STUDY OF EOEEST ENVIRONMENT. 169 



growth, particularly were too crude; no means was at hand of 

 determining closely when growth began, how rapidly it proceeded, 

 when it ceased. In consequence, phenological observations have 

 fallen into disrepute. 



The object of these conclusions is to suggest that, after all, in the 

 study of ecology there is nothing more important than the behavior 

 of the plant itself, its reactions at various times and seasons ; in other 

 words, phenology in the fullest sense. Otherwise, ecological studies 

 may as well be left to climatologists and soil physicists. 



How, then, may observations on the plant be made worth while? 

 The observable external phenomena which accompany a reaction to 

 certain environmental conditions must be measured more precisely 

 than in the past if they are to serve any useful purpose. There is 

 room here for instrumental development, quite as much as in the 

 study of the environment. The field has been even more neglected. 

 Again, there is opportunity for studying changes in the plant 

 through internal physical and chemical conditions. This brings this 

 study directly into the field of phj^siology, which can not be covered 

 further than has already been done. Finally, experimental physi- 

 ology, or the study of reactions to a limited change in environment, 

 most of the conditions being stable and under control, is necessarily 

 a laboratory study. The nature of the studies involved has been 

 indicated in preceding discussions, especially in connection with 

 light and soils studies. They may have a very useful result in show- 

 ing how better to study conditions in the field, but they do not take 

 the place of field observations. The reactions produced by changing 

 one factor while other conditions are more or less perfectly con- 

 trolled, may not be at all the same as in the field where all the factors 

 vary synchronously. After all, then, the problem for the ecologists 

 simmers down to one of determining plant reaction in the field as 

 closely as possible. 



In the past the plant society has perhaps been used too much as 

 an index to reactions; that is. the effect of environmental conditions 

 has been judged almost wholly by end results, in which competition 

 plays an important part. A plant is either absent from a given site, 

 occas onal, abundant, moderately successful, or vigorous and domi- 

 nant. Fijpm this is judged the extent to which the species is 

 favored or inhibited by the environmental conditions that have been 

 measured. 1 his method is altogether too gross and undoubtedly has 

 Led to a great many erroneous conclusions. A great deal more is to 

 be learned as t<> the requirements of different species by closer ob- 

 sen ation of individuals. 



