198 



BOTANY OF THE LIVING PLANT 



as the swollen corm for the succeeding season. The membranous 

 bases of its withered leaves cover the corm externally, while their 

 axillary buds may provide additional corms. The perennation is 

 t h U s carried out by a sympodial series of storage-corms (Fig. 131). 

 Similar distended axes are found in many other perennials, e.g. the 

 Tuberous Buttercup (Ranunculus bulbosus), and the Pig-Nut (Cono- 

 podium denudatum). In other cases the storage is in lateral branches 

 borne in large numbers, as in the Potato and Jerusalem Artichoke. 



Fig. 132. 

 Bulb of the Hyacinth. A , seen externally ; B, in median section. (After Figuier.) 



These will be considered later in relation to vegetative propagation, 

 to which such developments readily lead. The bulb, as in the Hya- 

 cinth, Snowdrop, or Lily, is similarly an upright, abbreviated, perennial 

 shoot, with its growth interrupted by dormant periods. Its biology 

 corresponds to that of the corm ; but here the chief storage region is 

 not the axis, which remains small and broadly conical, but the bases 

 of the leaves. The w r hole bulb is in fact a perennating bud, the apex 

 of which terminates in a flower, or inflorescence, while the growth is 

 then continued by one or more leafy buds formed in the axils of the 

 storage leaves (Fig. 132). The plants quoted are sufficiently distinct 



