1917] 



LOEB—BR YOPII YLL UM 



35 



When the leaf is at the apex and above (fig. 22), geotropic curvature 



of the stem occurs, but not so ranidlv as when the leaf is helnw- 



the location of the curvature is again in the region of 

 and basally from the second node behind (basally from) 



When the leaf is at the base and above 

 (fig. 23), no curvature ensues, at least for a long time. 

 The drawings were made on the seventeenth day. 



The correlation between root formation and geo- 

 tropic curvature is again striking. When in a longi- 

 tudinally split stem the apical leaf is preserved and 

 the cortex below, as in figs. 18 and 22 , root forma- 

 tion occurs in the second node behind the leaf, in the region 



