1917] 



LOEB—BRYOPHYLLUM 



29 



It is noticeable, incidentally, that while the leaf at the base 

 accelerates the shoot formation, the one at the apex accelerates 

 root formation. The more rapid geotropic curvature occurs in 

 those stems in which the root formation is favored. 



Aside from the influence of the position of the leaf upon the 

 velocity and extent of the curvature, an equally striking influence 

 exists between the position of the leaf and the localization of the 



curvature 



When the leaf is at the anew, the curva 



I 



Fig. 5 



ture appears near the second node behind 

 asally from) the leaf (figs. 3, 4), and is 

 confined chiefly to this region and possibly 

 to the next node located more basally. 

 The drawing was made 10 days after the 

 experiment began. 



Figs. 5, 6, and 7 are drawings of stems 

 with one leaf left at the base suspended in 

 the same jar simultaneously. In this case 

 little curvature takes place and the curva- 



hich 



Fig. 6 is an extreme case. It 

 increases with the length of the pi 

 basal leaf. The photograph in fig 

 the localization of curvature accor 

 at the apex or at the base. 



In the experiments thus far men 



is near the region where the leaf is located. 



It seems that the amount of curvature 



also 



of the 



When the leaf is left on the upper 



