38 



BOTANICAL GAZETTE 



[JANUARY 



\ 



Stems split lengthwise and with a leaf left at the most apical node 

 were put horizontally into a jar saturated with water vapor. One- 



\ half of the stems w r ere put with the cortex above 



\ (fig. 20), and one-half with the cortex below (fig. 



17). Only the latter bent geo tropically, the others 

 \ showing only a slight concavity on the upper side. 



which may have been partly of a geotropic char- 

 acter, but which more 

 likely was for the greater 



entire!}' , due 



\ 



\ 



1 

 1 



. 



» 



Fig. 22 



\ 



\ 



\ 



\ 





\ 



\ 



\ 



Fig. 23 



the longitudinal direction 



tendency 



