THE PROBLEM OF SEX IN PLANTS 



347 



entire new plant. A leaf of begonia laid on moist sand 

 will give rise to several new plants wherever it is cut (Fig. 

 254). Leaves of the sundew (Drosera) frequently strike 



Vr-^ 



Fig. 253. — Regeneration at the leaf-base of potato leaves {Solarium 

 tuberosum), a., roots formed; b, tuber-like enlargement; c, same as b, 

 with roots; d, formation of true tuber. (After Miss Elsie Kupfer.) 



Fig. 254. — Young plantlets developing from the edges of lacerations 

 made in a large leaf of Rex begonia. 



root at the tip and develop new plants (Fig. 255), while 

 the leaves of Bryophyllum normally produce marginal 

 buds from which new plants develop (Fig. 256). As 



