PROPAGATION. 



227 



II. — Propagation by Bulbs, Corms, and 

 Tubers. 



A Bulb is composed of either modified leaves 

 in the form of scales, as in Lilium, or the bases 

 of ordinary leaves folded round each other, 

 as in Crinum, and held together by a more or 

 less flattened axis, in the centre of which is the 

 growth bud or buds which never elongate, the 

 flower stem being produced separately from the 

 base of one of these buds. The best illustration 

 of this manner of growth is seen in the bulb of 

 Lilium. So long as the growth bud remains 

 solitary, only one bulb is formed, but when 

 more buds are developed the bulb divides into 

 several Some bulbs rarely multiply in this 

 way, whilst others do so very freely. In the 

 latter cases propagation is accomplished nat- 

 urally, all that the cultivator requires to do 

 being to separate the bulbs as soon as convenient 

 and grow them on. But for those bulbs which 

 do not divide, artificial means are resorted to 

 for the purpose of multiplication. The central 

 bud is cut out, or destroyed with a pointed 

 stick, and this causes the bulb to develop lateral 

 buds. Or the base is divided into four or 

 more pieces, and this results in the formation of 

 numerous bulbils. Choice Hyacinths are largely 

 propagated in this way, as also are Pancratiums 

 and Crinums, in fact any true bulb that is 

 strong enough to bear the treatment. Bulbs 

 with scales, such as Liliums, may be propagated 

 by breaking off the scales and pricking them 

 separately into pans of sandy soil. Most Liliums 

 may be readily and abundantly increased in 

 this way. Some Liliums form bulbils in the 

 axils of the leaves, and these may be removed 

 and planted. 



Many bulbs develop offsets from the base, 

 as, for instance, in Crinum, Pancratium, Hip- 

 peastrum, and Narcissus, which may be removed 

 for purposes of propagation. 



A Corm is a short, solid, fleshy, more or less 

 conical stem, from which roots spring chiefly 

 below, but also on the sides and upper portion; 

 the buds also are scattered over the upper sur- 

 face. Some of the buds grow into new corms 

 which supplant the old one, as in Crocus, Col- 

 chicum, Gladiolus, &c. ; or the corm is perennial, 

 as in Cyclamen, Caladium, and Amorphophallus. 

 Nearly all corms multiply themselves freely, 

 and it is not therefore often necessary to do 

 more than remove the young offsets and grow 

 them on. Gladiolus and Watsonia produce 

 numerous small basal corms called 'spawn'; 

 they also develop clusters of small corms on 



the flower-stems. Caladiums are propagated 

 by cutting off the 'eyes' (buds) which are 

 developed all over the upper part of the corm. 

 Arissemas, and in fact nearly all Aroids of this 

 character, are readily multiplied in the same way. 

 A Tuber is a short thickened rhizome or stem, 

 bearing buds and node-like scars, the best ex- 

 amples being the Jerusalem Artichoke, the 

 Potato, and the Yam. The fleshy subterranean 

 growths of the Dahlia are not true tubers, but 

 simply fleshy roots, as they do not bear buds, 

 but are reservoirs. The root-stock of some 

 Nymphseas and of Nelumbium are tubers. Pro- 

 pagation by means of tubers is simply stem 

 division, and wherever a bud can be severed 

 with a portion of the fleshy stock, it may be 

 utilized. 



III. — Propagation by Division. 



Strictly speaking, propagation in every way, 

 except by seed, is effected by division. If we 

 propagate by cuttings, suckers, grafts, or buds, 

 we must, in either case, divide the plant to obtain 

 them. Propagation by division is, however, 

 usually understood to imply the parting of such 

 tufted plants as Orchids, Bamboos, Ferns, and 

 Sunflowers, each part having roots, and, if pos- 

 sible, growing points. The most favourable 

 season for this operation is the spring. It is 

 surprising how much better results may be ob- 

 tained by lifting big tufts of plants, dividing and 

 replanting them, than is possible if they are left 

 undisturbed year after year. Valuable Orchids 

 often can only be multiplied by division. The 

 same may be said of Bamboos, for which it is the 

 only practicable means of increase, seeds being 

 rarely available. A diantum farleyense is a familiar 

 example among many ferns, for the propagation 

 of which division is the only means. It is not 

 possible, of course, to safely divide plants which 

 do not grow in a more or less tufted manner. 

 On the other hand, it may be accepted as a 

 general rule, that all plants of tufted habit, in- 

 cluding even some palms, may be increased by 

 division. The herbaceous perennials that have 

 annual stalks can be divided with a spade or 

 trowel; and such plants as Gentians, Saxifragas, 

 or Box can be dug up and split into slips with 

 some portion of root to each. In some cases, 

 the number of plants which can be obtained by 

 division may be greatly increased by introduc- 

 ing a quantity of fine soil among them, in order 

 that the lower branches may strike root in it : 

 or the plants may be taken up and replanted 

 deeper than before. 



