46 



STEMS. 



[sErTio: 



Mkk^> 



That of Iiidiau Turnip is formed oue year and is consumed the uext. Fig. 

 lOi represents it in early summer, liaving below the corm of last year, from 

 which the roots have fulleu. it is partly consumed by the growth of tlie 

 ._^^ stem for the season, and the 



f \\\ corm of the year is forming 



\\ ^ at base of ihc stem above 



'"'^^^-^ the line of roots. 



112. The corm of Crocus 

 (Fig. 105, 106), like that 

 of its relative Gladiolus, is 

 also reproduced annually, 

 the new ones forming upon 

 the summit and sides of the old. Such a corm is like a tuber iu bud- 

 ding from the sides, i. e. from tlie axils of leaves ; but these leaves, instead 

 of being small scales, are the sheathing bases of fo- 

 liage-leaves which covered the surface. It resem- 

 bles a true bulb iu liaving these sheaths or broad 

 scales ; but in the corm or solid bulb, this solid part 

 or stem makes up the principal bulk. 



113. The Bulb, strictly so-called, is a stem like 

 a reduced corm as to its solid part (or plate) ; 

 while Ihe main body consists of thickened scales, 

 which are leaves or leaf-bases. Tliese are like bud- 

 scales ; so tliat in fact a bulb is a bud with fleshy 

 scales on an exceedingly short stem. Compare a 

 "VTliite Lily bulb (Fig. 107) with the strong scaly 

 buds of the Hickory and Horse-chestnut (Fig. 72 

 and 73), and the resemblance will appear. In 

 corms, as ui tubers and rootstocks, the store of 

 food for future growth is deposited in the stem ; 

 while in the bulb, the greater part is deposited in 

 the bases of tlie leaves, changing them into tliick 

 scales, which closely overlap or enclose one another. 



114. A Scaly Bulb (like that of the Lily, Fig. 107, 108) is one in 

 the scales are thick but comparatively narrow. 



115. A Tunicated or Coated Bulb is one in which the scales enwrap 

 each other, forming concentric coats or layers, as in Hyacinth and Onion. 



licli 



Fig. 103. Corm of Cyclamen, much reduced in .size : roots from lower face, leaf- 

 stalks avul flower-.stalks from tlie upi)er. 



Fio. 104. Conn of Imlian Turnip (Ari.s»ma). 



Fig. 105 C'orm of a Crocus, the investing sheaths or dead leaf-bases .stripped 

 off. The faint cro.ss-lines represent the scars, where the leaves were attached, i. e. 

 the nodes : the spaces between are the internodes. The exhausted corm of the 

 previous year is underneatli ; forming ones for next year on the summit and sides. 



Fig. 106. Section of the same. 



