LILIACEjE 



233 



sometimes borne in the axils of the leaves, and these may also 

 develop into flower shoots. 



Leaf. — The first foliage leaf emerges from a slit in the 

 cotyledon. All leaves are very thick and fleshy, and over- 

 lapping. There is no petiole. The oldest leaves are on the 



Fig. 90. — A, base of stem of common onion (Allium cepa) showing hollow 

 leaves cut across; B, cross-section of hollow stem of same: C, base of stem of 

 leek (Allium porrum) showing flattened solid leaves; D, cross-section of solid 

 stem of same. 



outside of the bulb, while the younger appear toward the 

 inside. In a longitudinal section of the bulb, it will be noted 

 that these younger leaves, coming from within, are higher 

 on the compressed stem than the older (Fig. 14). The 

 edible portion of the common onion, and of some other 



