SUBTEERANEAN LEAF-BUDS, BULB, AND OOEM. 



115 



disc or round flat portion formed by the bases of the lateral buds from 

 ■which the fasciculated roots, r, proceed, e the scales or modified leaves, 

 and / the true leaves. In the vertical section (fig. 225), h is the new 

 bulb, formed like a bud in the axil of a scale. The new bulb some- 

 times remains attached to the parent bulb, and sends up an axis and 

 leaves ; at other times it is detached in the course of growth, and 



Fig. 224. 



Fig. 225. 



Fig. 226. 



forms an independent plant. The new bulbs feed on the parent one, 

 and ultimately cause its absorption. The scales are sometimes all 

 fleshy, as in the scaly or naUed hull of the white lily (fig. 226 e e e), 

 or the outer ones are thin and membranous, overlapping the internal 

 fleshy ones, and forming a tunicated bulb, as in the Onion, Squill, 

 Tulip, and Leek (fig. 224). 



The scales in bulbs vary in number. In Gagea there is only one 

 scale ; in the Tulip and Fritillaria imperialis they vary from 2 to 5 ; 

 while in Lilies and Hyacinths there are a great number of scales. In 

 the Tulip a bud is formed in the axil of an outer scale, and this gives 

 rise to a new flowering axis, and a new bulb, at the side of which 

 the former bulb is attached in a withered state. In some Liliaceous 

 plants the bulbs continue for two or more years. The bulb may 

 bear on the same axis growths belonging to two seasons ; or it may 

 bear numerous growths or shortened axes of several years. In the 

 common hyacinth -there may be seen axes of four distinct generations 

 on one bulb. 



The OoEM (xo^//,6s, a stump) has already been noticed under 



Fig. 224. Tunicated bulb of Allium Porrum, or the Leek, r. Boots, p, A circular disc, 

 or shortened stem intervening between the roots and the bulbous swelling, e e. Scales or 

 subterranean modified leaves. /, Upper leaves which become green. Fig. 225 Vertical 

 section of the tunicated bulb of the Leek. The letters indicate the same parts as in the 

 last figure, h, Bud situated in the axil of a scale, which, by its development, forms a new 

 bulb. Fig. 226. Scaly or naked bulb of Lilium album, r, Boots, eee, Scales or modified 

 underground leaves, t, The flowering axis, cut. 



