TRANSPIRATION AND ASSIMILATION 215 



TABLE XXXII 



Transpiration of Meadow and Steppe Plants 



The assimilation is found to vary very greatly in different 

 plants, when expressed in relation to dry weight as Iljin 

 prefers ; the mesophytes assimilate more vigorously. If 

 the assimilation is related to the amount of water tran- 

 spired, then the xerophytes are shown to lose less water in 

 assimilating a unit amount of carbon dioxide. This is 

 sometimes the case when the two classes are compared each 

 in its own environment ; it is much more marked when the 

 mesophyte is allowed to assimilate in a xerophytic 

 environment. These relations are shown in Table XXXIII. 



TABLE XXXIII 

 Assimilation related to Transpiration 



Iljin's conclusion is that the xerophytic plants of the 

 steppe can survive in the arid conditions because they are 

 able to assimilate more vigorously with a limited water 



