No. 529] 



ORGANIC RESPONSE 



31 



The removal of plants from localities with well-marked 

 seasons to equable maritime climates is followed by a 

 leaf development which may result in the multiplication 

 of the parts. Frag aria. All introductions in which 

 the range of climatic conditions to which the plant was 

 subject was narrowed, were followed by increased vege- 

 tative activity, which multiplied underground branches 

 and propagative bodies. 



The concurrence of these responses in a single form 

 may be well demonstrated by the results of studies of a 

 genotype near Scrophularia leporella, found in the vicin- 

 ity of the montane plantation, which has survived in the 

 shade at the Desert Laboratory and at the seaside locality. 

 In its native habitat, it shows a strict, scarcely branch- 

 ing shoot with a few fleshy succulent roots, which appar- 

 ently carry water with a small dissolved content. When 

 this form is taken to the Desert Laboratory, its repro- 

 ductive season is lengthened from two months to five or 

 six months, although but few seeds are formed, the shoots 

 branch more profusely, and a greater mass of under- 

 ground members are formed. In the maritime location 

 these features are accentuated and the development of 

 branches goes on to such extent that the shoot gives rise 

 to a number of main branches which can not be supplied 

 with water, and hence soon wilt and die. The under- 

 ground system now includes dozens of thickened members 

 from one to two centimeters in diameter, which may show 

 a total weight of from 6 to 8 kilograms. 



The removals of forms included in the experimental 

 series may be taken as fairly parallel to the distributional 

 movements effected by various agencies without the in- 

 tervention of man. Some, as a matter of fact, are exact 

 duplicates of occurrences in which these same species 

 participate. The alterations noted are undoubtedly en- 

 vironic effects, and may be attributed chiefly to climatic 

 factors. Two common assumptions as to the behavior of 

 plants are to be noted when species are removed to local- 

 ities widely separated from the habitat in which they are 



