118 



OKGANOGRAPHT. 



solid, subterranean stem, of a rounded or oval figure, and com- 

 monly covered externally by thin scales. By Lindley it is 



Fig. 227. Fig. 228. 



Fig. 227. Corms of Croctis sativxis. a, I 

 the apex of the old or parent coim 



The new corms, arising from c, 

 -Fig. 228. Section of tlie former. 



defined " as the dilated base of the stem of Monocotyledonous 

 Plants, intervening between the roots and the first buds." By 

 some botanists it is considered as a kind of bulb, in which the 

 stem or axis is much enlarged, and the scales reduced to thin 

 membranes. Practically a corm may be distinguished from a 

 bulb by its being solid, whereas a bulb is formed of imbricated 

 scales. The corm is known to be a form of stem by producing 



Fig. 229. 



from its surface one or more buds, as in 

 the Crocus (^^f^. 227 and 228), Avhere they 

 ^ proceed from the apex, and ultimately 



r| .i destroy their parent by feeding upon its 



!i ;t^., accumulated nutriment. These new corms, 



in a future year, also produce others near 

 tlieir apex, which by developing at the ex- 

 pense of their parents destroy them in like 

 maimer, and these again form otlicr corms by 

 whicli they are tliemselves destroyed. In tliis 

 manner the new corms, as they are successively 

 developed, come gradually nearer and nearer to 

 the surface of the earth. In tlie Colchicum (^fi(j!. 

 229), tlie new corm is dcvcl()]icd on one side of 

 the old, near its base. This feeds u])on its parent, 

 Flo.220. Colchicum. ^'^'^ ultimately destroys it. and is in like 

 r. Roots. /. Leaf, mauiicr destroyed the ne.Kt year by its own 

 main?oni!.t'year''B P^'ireny. Thus, iu taking up such a corm 

 corm. <i". Corm of carefully, we find (Jig. 229), a, the slirivelled 

 «.".cZ'menceS fo^''" ^'^ ^^^^ .VP^r ; «", that of the present 

 of the corm of next season, wliicli, if cut vertically, shows a'", the 

 y*^**"' corm, iu a young condition for tlie next year. 



All conns contain starch or otlicr nutritious matters, which 

 are stored up for the future use of their otFspring. 



