No. 529] 



ORGANIC RESPONSE 



27 



the cultures,, it is found profitable to re-introduce forms 

 from the original or control lot of various species in 

 order to follow the first stages of their adjustment re- 

 peatedly. 



The earlier introductions were made in May, 1906, but 

 the establishment of the system was not completed until 

 early in 1909. Some of the species have therefore been 

 observed through the fourth growing season in newly 

 encountered habitats, and as the somatic responses are 



immediate or nearly so it may be assumed with some con- 

 fidence that the alterations observed are those which are 

 to be tested as to their transmissibility. It may be of 

 interest to note briefly some of the more salient alterations 

 with some attention to their geographical significance. 



suitable occasion. 



1. Many species of perennials native to regions in 

 eastern America with a temperate summer or growing 



