B U L 



tliis opinion we have the fatisfaftion to flucl thnt we are fup- 

 ported by the authority of Dr. Smitli. See Eiighlh Botany, 

 p. ijo. The granules of the white faxifragc, which l^a 

 Marck confiders as tubers, more nearly rcfeaible the proper 

 bulb, being feated on the defeending caudex, which throws 

 out radicles beneath them, and may he regarded as bear- 

 ing fome affinity to what Linnxus calls flem-bnlbs, though 

 he has conllru6ted his definition of the term bulb fo as to ex- 

 clude them. They are placed either in the axils of the 

 Laves, as in liliuin bulbifcruni, dentaria bulbifera, 5ic. : or 

 on the common receptacle of the head of flowers, as in feve- 

 ral fpecies of allium : or, within the calyx, indead of a pro- 

 per feed, as in polygonum viviparnm. Botauills have paid 

 Ittle attention to their natural liiftory ; and have, for the 

 nioft part, done nothing more than announce their exlllence. 

 AVe know not that any inquiry has ever been made, whether 

 thofe which are found in the thiee very different fitu.itions 

 j'.ill mentioned are precifcly of the fame nature and Itrufture, 

 or whether they do not fo far differ from each other as to 

 render it expedient to give them dillingnifhing names. It 

 iippears, from Dr. D-irwin's defcription of what he calls the 

 iiimmit bulbs of allium magicum, that in every thing but 

 fituation tl/ty are cxaftly hmilar to the root bulb of that 

 raid other kindred plants. " In cutting one of them hori- 

 zontally," he tells us in his Phytologia, " I obferved three 

 young bulbs inclofed in the concentric ilefhy membranes of 

 the fummit bulb in the following manner : five thick, flediy, 

 concentric coats of the general fummit bulb being taken 

 away, there appeared one fingle naked fmall bulb ; and on 

 the fixth coat being removed, two other bulbs became 

 vifible, which were included in it." A philofophic view of 

 all the different methods in which plants are propagated 

 without the intervention of an impregnated germ ; and of 

 the order in which they are conncftcd together, fo as to 

 form a regular gradation from the gem or proper ftem-bud 

 to the tuber of the common potatoe and the tubercles of 

 vicia, lathyroides, and many other plants, is one of the 

 mimerous djfiuerata in vegetable phyfiology. The hillory 

 of bulbs ahme would require a long courfe of experi- 

 ments. 



Bulb, in Vcgctahh Anatomy. This term is commonly 

 applied to the enlargements o! the roots of many herbaceous 

 plants, which are therefore faid to poffefs bullous roots. See 

 Bulbous Roots. The true bulb, however, does not in l^rift- 

 nefs conlHtute any part of the root, but in its llrufture and 

 ufes bears a perfeft analogy to the bud. See Bud. Bulbsare 

 in fome inllances met with in the axilliE of the leaves, as in 

 the lilium bulbifirum, and even in the flower itfelf, in many 

 fpecies of allium and agwuf ; but their mofl ulual fituation 

 is upon the root. It is there that they are found in the 

 hyacinth, tulip, the lilies, the common onion, and a number of 

 the herbaceous monocotyledons. The root in all thefe in- 

 ftances is an irregular circular plate, from the lower part of 

 which proceeds a tuft of the fine or fibrous roots ; the upper 

 part fullains the bulb. 



The bulb is compofed of a number of laminse, which are 

 placed one upon another ; and contain in their centre the 

 embryo of the plant. 



When the lamina; have not been expofcd to the air, they 

 are thick, and loaded with juices, are generally of a white 

 colour, and confill chiefly of parenchyma, in which are 

 fpread fome fibres, forming nervures. They reftmble very 

 much etiolated leaves. 



When the bulbs have been removed from the earth, and 

 kept for any length of time in an open and dry fituation, the 

 external layers flirink up, become thin and gloffy upon the 

 furface, and often acquire a brilliant metallic colour. 



B U L 



The lamlnne in the onion, hyacinth, tulip, and many others, 

 confill of circular tunici, the one entirely enveloping the 

 other; but in the //7;Vj they alfnme the form of fcales, and 

 more exaftly correfpond with the coverings of buds. Sec 

 Plate \\. in Fegetahlc Anatomy ; fig. iS. fliews the bulb and 

 root of the onion; a is the bulb, wh'ch has the fupcrior part 

 cut off to bring into view the concentric layers of which it is 

 compofed ; h indicates the circular pl.-.te forming the com- 

 mon centre of the fibrous roots, which arc mnikedby c. 

 Fig. 1 9. of the fame plate exhibits the bulb of a lily, wliicU 

 is made of thick imbricated fcales; from the bafe wliieh fup- 

 ports the fcales the fibrous roots take their origin. 



The pulpy Liminx, which conllitute the great mafs of 

 all bulbs, are analogous to the fcales of the bud, and, like 

 them, ftrve to protcil the young plant or flower from all 

 external influences, until the embryo attains a certain degree 

 of developement, or becomes vigorous enough to be nounlhed 

 by its own independent actions. Tiie embryo in the bulb, 

 as in the feed and bud, is always formed in the year pre.* 

 ceding its evolution. Thus we may clearly difccrn in the 

 bulb of tlie tulip., as early as the month of Aui^ult, the linea- 

 ments of the flower which is to make its appearance the en- 

 fuing April. S^t Plate \\. oi Fegetalle Anatomy. Fig. 20^ 

 reprefents a bulb of the tu'ip, cut down through tlie middle in 

 the month of September ; a a the various inveifments of the 

 bulb ; b b the innermoll tunics, thinner than the reft, and 

 containing the young flower ; c the embryo tulip, implanted 

 as it were in the circular root, which fcrves as the bafis oF 

 all the parts of the bulb ; d the circular plate, or common 

 radicle. 



As bulbous plants do not produce buds in the axillas of their 

 leaves, the circular root, which fupports the bulb, gives origiii 

 to fmall bulbs, which are in m.any refpcfls analogous to the 

 lateral bud'. They exift, like thttn, for a certain period in 

 an immature or embryo Hate, inclofed by the leaves or tunics 

 of the parent bulb. Tiicy are formed in many fpecies at the 

 comm.encement of the feafon of vegetation ; when thev be- 

 come apparent, tliey are as fmall as a grain of corn ; they 

 increafe at firft flowly, but afterwards they grow witli 

 rapidity, and when the flower is ready to blow, they acquire 

 fibrous roots preparatoiy to their detachment from the 

 parent bulb. When the root-buds approach maturity, tlie 

 bulb, from whence they arife, ceafcs to vegetate, and ulti- 

 mately dies and rots. It is in this manner that the root of a- 

 tulip becomes apparently removed from its fituation, the 

 original bulb bemg replaced by others which produce the 

 flowers of the following year. 



There are fome bulbs, as thofe of the hyacinth, which fur- 

 nifli, for feveral years, the lateral bulbs or root-buds ; but in 

 thefe cafes it is only at the end of two or three years that the 

 fmall bulbs attain the magnitude of the original one. Jf, 

 however, they be detached during the firft year, they will 

 grow independently of the parent bulb, which in this cafe 

 does not perifh, but continues to exift for feveral years, and 

 to produce new offsets. 



Bulbs, like buds, may be diftinguiflied into leaf bulbs and 

 flo'-iver bulbs ; as an example of which, let a feed of tulip be 

 fown, it produces in the firft fnmmer a plant, which dies in 

 the autumn, but leaves in the earth one or more bulb?. Thefe 

 afford ftronger plants, the enfuing fpring, than thofe of the 

 firft year, but which do' not yet bear flowers. They alfo 

 perifh in the autumn, and leave behind them other leaf 

 bulbs, ftronger or more perfect than thofe of tfie preceding 

 year ; and a fuccefTion of leaf bulbs is thus generated for four 

 or five years, until at length the bulb acquires foflicient 

 vigour for feminal generation ; and then it produces, in its 

 place, a large flower bulb, funounded by feveral leaf bulbs. 



BULBINE,- 



