3S6] BUL Or near the root of certain herbaceous plants, which are therefore deno- minated bullous. Linx^us con- siders the bulb as the winter-quar- ters of the future vegetable; be- cause every bulb contains, in mi- niature or embryo, a plant, in all respects similar to its parent ; so that many plants and trees may be propagated, with equal facility, by the bulbs or buds, as well as by the seeds. The tender rudiments of the future vegetable, of which the bulb or bud is composed, are inclosed, and, during the severities of winter, defended against cold, and other external injuries, by a hard bark, or rind., which generally consists of a number of scales, placed OVer each other, like tiles, and fastened together by means of a tenacious, resinous, and frequently odorifer- ous substance. Thus defended, the buds remain upon different parts of the mother plant, till the ensuing spring. Bulls are distinguished from TucLs, by this circumstance, that the former are generated on the broad caudex of the plant within the ground, or in contact with it, and immediately shoot down their roots into the earth ; whereas, buds are formed above the soil, on the long caudexes which constitute the fila- ments of the bark of trees, and shoot down new roots from the lower end of those elongated trunks. Dr. Darwin observes, that bulbs may be divided into leaf and flower- bulbs. When a tulip seed is sown, it produces a small plant the first summer, which in the autumn dies, and leaves in its place one or more bulbs. These are leaf- lul Is, which, in the ensuing spring, rise into stronger plants than those of the first year, but no flowers are yet BUL generated : in the autumn, these perish like the former, and leave, in their places, other leaf-bulbs, stronger, or more perfect, than their preceding parents. This succession continues for four or five years, till at length the bulb acquires a greater perfection or maturity, necessary for seminal generation, and pro- duces in its place a large flower- bulb in the centre, with several small leaf-bulbs around it. This successive formation of leaf- bulbs in bulbous-rooted plants, pre- vious to the formation of ajloicer- lulb, is curiously analogous to the production of leaf-buds on many trees for several years, before the production of flower-buds : thus, apple-trees, raised from seeds, ge- nerate only leaf-buds for" ten or twelve years, and afterwards annu- ally produce both flower and leaf- buds. Hence it appears that the adherent lateral or paternal pro- geny, being the most simple and easy, is consequently the first mode of re-production ; and that the pro- pagation by seed is not accom- plished till the maturer age or more perfect state Of Che rarent-bud. Bullous mots are said to be solid, when composed of one uniform lump of matter, as in the tulip ; funicated or coated, when formed of a plurality of coats, surrounding one another, as in the onion; sqaa- mous, or scaly, when composed of lesser scales, as in the lily ; jointed, as in the tuberous moschatel ; du- plicate, when there are only two bulbs to each plant, as in the crocus and saffron ; and aggregate, when there is a congeries of such roots to each. One of the most striking phe- nomena in vegetable nature, is that of raising plants from their bulbs, without earth, Duhamel even raised
