454 Vegetation of Plants having solid Bulbs, 



cept the threads, or filaments, at e, which are more or less appa- 

 rent, and which cross it vertically, proceeding from each ol' the 

 tubercles before mentioned. 



It has been observed, that, as soon as vegetation commences, 

 the offsets of the bulb send down from their base or side one or 

 more large fusiform roots [h h), which have their origin in the 

 internal part, or germ, of the solid substance above described. 

 Whether these are intended to assist the circumferential fibrous 

 roots in the office of absorption, need not be discussed here, as it 

 is apparent that these latter cannot absorb sufficient matter for the 

 formation of the offsets: and this is proved more fully, by ob- 

 serving that there are sometimes no fusiform roots when only one 

 offset is developed ; the circumferential roots, in that case, ap- 

 pearing to be sufficient for its nourishment. 



As vegetation proceeds, the offsets are found to augment in 

 bulk ; but, when observed internally, their germs are found not 

 to have increased at all, and that only the parts which surround 

 them are enlarged; so that, when the bulb is completely developed, 

 the germ has vanished, leaving only a faint trace of shade, show- 

 ing where it has been, and which may be observed in the lower 

 part of the bulb. 



In proportion as the offsets become larger, the parent bulb 

 diminishes, becomes yellow, and dried up, presenting only a fi- 

 brous cellular structure ; which, when the new bulb has attained 

 its utmost growth, becomes black, and dwindles away to a very 

 small substance, that, sooner or later, disappears altogether. 

 The circumferential roots decay with the bulb, and the fusiform 

 roots also ; the leaves become yellow, wither, and finally rot 

 off; and their bases, w^hich have become the inner coats of the 

 dried bulb, with their internal sheaths, remain as the involucrum 

 of the offset. The bulb thus passes on into its dormant state, 

 presenting the above described characteristics. 



The newly formed bulbs, which, at first, participated in the 

 vitality of the old ones (by means of the prolongation of their 

 germs, which united nearly in the centre of the old bulb, and were 

 the origin of the circumferential roots), now enjoy an individual 

 vitality : they have no longer any germ, as that by degrees 

 has withered, and finally disappeared ; and these bulbs, in their 

 turn, can now only be considered as a mass of matter containing 

 the germs of new plants, which are to be developed at the next 

 season of vegetation. 



I have observed that the manner in which the bulbs of the 

 Gladiolus communis vegetate is very little different from what 

 I have just described. 



The Colchicum autumnale also differs but little from the cro- 

 cus in the manner of reproducing its bulbs ; with the exception 

 that in the colchicum the offsets always appear at the side of 



