3° 



BOTANICAL GAZETTE 



[jAN'U AR Y 



horizontally suspended stem, the geotropic bending is slower than 

 when it is on the lower side, but the bending will also be much more 

 rapid and more intense when the leaf is left at the apex (figs. 8, 9, 

 10) than when it is left at the base (figs. 11, 12, 13). In the latter 

 case the bending is again slight, and what little curvature occurs 

 is confined to the immediate neighborhood of the basal leaf. Fig. 13 



is an extreme case. If the leaf is at the apex, 



curvature. 



the curvature takes 



of the second node or behind (basally from) 



the second node. 



ft 



A study of these stems revealed a remark- 

 able correlation between root formation and 



stated already 



when the leaf is located at the apex it favors 

 root formation in the rest of the stem, and 

 when it is at the base it favors shoot forma- 

 tion but inhibits root formation in the whole 



stem located apically 



■ 



the leaf. 



agrees with the idea that the leaf sends root- 

 forming substances toward the base and shoot- 

 forming substances toward the apex. We notice that the geotropic 

 curvature is favored or accelerated most in those stems in which 

 an apically located leaf is left, and in such stems root formation is 

 favored also. The correlation between root formation and geo- 

 tropic curvature is still more striking, however, if we consider the 

 location of the roots formed- When the leaf left is at the apex, 





