LECT. IV.] THB ROOT. BULBS. 165 



or from a simple scale, when it is solid ; and these 

 situations of the roots form the chief characteristic 

 of the bulb, distinguishing it from the tuber, and 

 marking out those limits between the bulb and 

 the tuber, ,the existence of which is denied by 

 Mirbel * and some other authors : for the roots of 

 the plant borne on a tuber, whether of the closely 

 attached or pendulous kind, always proceed from 

 the stem. 



Bulbs, like tubers, are reservoirs of nutriment 

 for the developement and temporary support of 

 the plants formed within them ; a fact which is 

 illustrated to common observation by the growing 

 of onions, in the storeroom of the housewife. 

 Young radical bulbs, as I shall soon have occasion 

 to show you, are produced in some instances above, 

 in others below, and in others again within, or at 

 the sides of an old bulb, during the adult vegeta- 

 tion of its plant ; and are, like the gems formed 

 on the surface of a tuber, the lateral progeny of 

 the plant itself, not of the bulb. They are more 

 frequently formed previously to the flowering of the 

 parent plant; and as they preserve the plantule 

 within them, until the ensuing spring, they are re- 

 garded as winter habitations (hybernacula) by Lin- 



* " II n'y a point de limites entrela bulbe et le tubercule; la 

 " transition se fait de 1'une a 1'autre, par la bulbe solide qui 

 " participe de toutes deux." Elem. de Phys. veg. l ere partie, 

 p. 135, nota. 



M 3 



