Seeds grow readily and give good results, and they are usually produced freely, especially in the bulbous species. Sow as soon as ripe in light soil in some protected place. The bulbous species produce bulbels, which may be used for multiplication. The rhizomatous species are propagated by dividing the rhizome into short rooted pieces. Or when the rhizomes lie on the surface of the ground and do not root readily, they may be layered. =Isonandra= (Gutta-Percha Tree). _Sapotaceæ._ Insert cuttings in sandy soil, under glass, in heat. =Isoplexis=, Callianassa. _Scrophularineæ._ Cuttings of half-ripened shoots should be made in spring under glass. =Isopyram.= _Ranunculaceæ._ Propagated by seeds or by divisions, in autumn or spring. =Itea.= _Saxifrageæ._ Propagated by seeds or by suckers, in spring; and in autumn by layers. =Ivy.= See Hedera and Ampelopsis. =Ixia=, including Morphixia. _Irideæ._ Seeds may be sown in pans of sandy soil in autumn, and placed in a cool frame. Propagation by bulbels is a much quicker, as it is the usual method. =Ixiolirion=, Kolpakowskia. _Amaryllideæ._ Increased by seeds; and by bulbels. =Ixora.= _Rubiaceæ._ Seeds. Usually increased by short-jointed green cuttings placed in a close frame with a strong bottom heat. =Jaborosa.= _Solanaceæ._ Increased by seeds sown in spring, and by divisions, also by cuttings of young shoots, placed under a frame. =Jacaranda.= _Bignoniaceæ._ Cuttings of half-ripened shoots may be made in early summer and placed in sand over sandy peat, in heat, and kept shaded. Also seeds. =Jacobæan Lily.= See Amaryllis. =Jacobinia.= See Justicia. =Jacquinia.= _Myrsineæ._ Cuttings of ripened shoots, usually made in summer, placed in sand, in a moist bottom heat. =Jalapa.= See Mirabilis. =Jambosa.= See Myrtus. =Jasione= (Sheep's Scabious). _Campanulaceæ._ Seeds, sown in spring or fall, usually in the open. The perennials may be divided. =Jasminum= (Jasmine, Jessamine). _Oleaceæ._ Sometimes by seeds, but usually by cuttings of the nearly ripened wood, under glass. Cuttings of ripe wood are also employed, and layers are often used. =Jatropha.= _Euphorbiaceæ._ Cuttings made of firm young shoots will strike in sandy soil in a strong bottom heat. The cuttings, if very fleshy, may be dried a few days before setting them. =Jeffersonia.= _Berberideæ._ Seeds should be sown as soon as ripe, or divisions may be made. =Jerusalem Artichoke= (Girasole). See Artichoke. =Jessamine, Yellow.= See Gelsemium. =Jonquil.= See Narcissus. =Jubæa= (Coquito Palm of Chili). _Palmæ._ Propagation is effected by seeds. =Judas-tree.= See Cercis. =Juglans= (Walnut and Butternut). _Juglandeæ._