CH. VII] EPICOTYLS. 199 



of some of the Leguminosse is the part played by light in 

 the phenomenon. Wortmann 1 has shown that the epi- 

 cotyls of Phaseolus multiflorus remain curved in the dark 

 and straighten when exposed to light. We use the vetch 

 (Vicia sativa), in which the phenomenon is particularly 

 striking, the darkened epicotyl being often curled into a 

 complete loop. 



1 Hot. Zeitung, 1882, p. 915. 



