96 



STRUCTURAL BOTANY. 



[81, 82. 



above, a circle of adventitious roots around its base, 

 and a flowering stem from the terminal or a lateral bud. 



241. How multiplied. Bulbs are 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 detached. 

 Bulbs which flower from the terminal 

 bud are necessarily either annual or bi- 

 ennial ; those flowering from an axillary ' 

 bud may be perennial, as the terminal 

 bud may in this case continue to de- 

 velop new scales indefinitely. 



242. Bulbs are said to be 



tunicated when they consist 2C6,BuibofLiimm 



* & rhizome ; a, full grown bulb sending up a ter- 



of concentric layers, each en- ^ t al y f a e r m C) and two offsets 66) for the bulbs of 

 tire and inclosing all within 



it, as in the Onion. But the more common variety is 

 the scaly bulb consisting 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 tuber, the axis is excessively developed, while the 

 scales are reduced to mere linear points. In the corm the analogy is far more 

 evident, for the axis is less excessive and the scales more manifest; and 

 lastly, in the bulb the analogy is complete, or overdone, 'the scales often be- 

 coming excessive. 



270 



267, Corm of Crocus, with new ones forming above. 268, Vertical section of the same. 269, Section of 

 bulb of Hyacinth, with terminal scape and axillary bulblet. 270, Section of bulb of Oxalis violacea, with 

 axillary scapes. 



