52 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



till the tip of the prophyll had been stimulated by light. Still a third 

 experiment was made to determine the capacity of the plant for 

 piercing obstacles between its bud and light ; a number of corms 

 were buried to a depth of 25 cm. in loose garden loam and the pro- 

 phyll reached the surface of this substratum before opening. The 

 mechanical force exerted must have been very great. 



Fig. 12. Arisaona triphyllum. A, plant grown in portable dark chamber with 

 occasional exposure to diffuse daylight. B, etiolated bud shortly after opening : an 

 apical portion of the prophyll is borne on the tips of the leaf. 



Roots were not sent out from the crown of the corm until about 

 the time of the maturity of the leaves. The petioles are normally 

 about equal in length, but in etiolated cultures one was often much 

 longer than the other. The laminae did not unfold when the cultures 



