FORMS OF SCALE- STEMS. 



81 



240. THE BULB partakes largely of the nature of the bud. It 

 consists of a short, dilated axis, bearing an oval mass of thick, 

 fleshy scales, closely packed above, a circle of adventitious roots 

 around its base, and a flowering stem from the terminal, or a 

 lateral bud. 



\ 



863, Corms of Putty-root (Aplectrum); o, of last year ft, of the present year. 264, Scale-lmlb of White 

 Lily. 265, Scale-bulb of Oxalis violacea. 



241. How multiplied. Bulbs arc renewed or multiplied annually at the approach of 

 Winter by the development of bulbs from the axils of the scales, which increase at the 

 expense of the old, and ultimately become de- 

 tached. Bulbs which flower from the terminal 

 bud are necessarily either annual or biennial ; 

 those flowering from an axillary bud may be 

 perennial, as the terminal bud may in this case 

 continue to develop new scales indefinitely. 



242. Bulbs are said to be tuni- 

 cated when they consist of con- 

 centric layers, each entire and 

 enclosing all within it, as in the a*. Boib of Liiium Buperhum, with haw*f 



a rhizome ; a, full grown bulb sending up a * * 



Onion. " But the more common SftfJS and two offsets ^ for the b 

 variety is the scaly bulb consist- 

 ing of fleshy, concave scales, arranged spirally upon the axis, as 

 in the Lily. 



243. The tuber, corm, and bulb are analogous forms approaching by degrees to the 

 character of the bud, which consists of a little axis bearing a covering of scales. In the 

 HilK-r. the axis is excessively developed, while the scales arc reduced to mere linear 



G 



