Seeds may be sown in spring in gentle heat. Half-ripened cuttings may be made in spring or autumn, and should be inserted in sandy loam, and placed under a bell-glass, in gentle heat. Also by root-cuttings. =Ilex=, including Prinos (Holly). _Ilicineæ._ Seeds, which should be stratified. They are often cleaned of the pulpy coat by maceration. The seeds rarely germinate until the second year. Varieties are perpetuated by graftage. The veneer-graft, upon potted plants, is usually employed, but other methods may be successful. Budding is sometimes performed. =Illicium= (Aniseed-tree). _Magnoliaceæ._ Seeds. Cuttings of young ripened shoots may be made during summer and should be placed in sandy soil, under a glass. =Imantophylium.= _Amaryllideæ._ Seeds. Usually increased by division or by means of bulbels. =Impatiens=, Balsamina (Balsam). _Geraniaceæ._ The common annuals may be raised from seeds, in spring, in any ordinary light soil. The stove and greenhouse species may be increased by seeds, or from cuttings, which root freely in a close frame. _I. Sultani_ does best from seeds. =Indian Fig.= See Opuntia. =Indian Shot.= See Canna. =Indigofera= (Indigo). _Leguminosæ._ Propagated by seeds. Cuttings of young shoots may be inserted in sandy or peaty soil under glass, in slight heat. =Inga.= _Leguminosæ._ Propagated by seeds. Cuttings root with difficulty. =Inula=, Elecampane. _Compositæ._ Readily increased by seeds or by divisions. =Ionidium=, Solea. _Violarieæ._ The herbaceous species are increased by seeds and by divisions. The shrubby sorts are increased by cuttings which will root in sand, in a frame. =Ipomœa=, including Quamoclit (Moon-flower, Morning Glory). _Convolvulaceæ._ All the annual species are grown from seeds. The perennials are also increased by seedage, but they may be raised from cuttings struck in a forcing-house or a frame. The moon-flowers often do better in the north from cuttings than from seeds. _I. Horsfalliæ_ is largely propagated by layers, and other species may be treated in the same way. Division is sometimes employed. _I. pandurata_ can be propagated by root-cuttings. Also grafted (see page 88). =Ipomopsis.= See Gilia. =Iresine=, Achyranthes. _Amarantaceæ._ Seeds rarely. Increased readily by cuttings. For summer bedding in the north, cuttings should be started in February or March. For use as window plants, they should be taken in late summer. =Iriartea=, Deckeria. _Palmæ._ Propagation is effected by seeds. =Iris=, including Xiphion. _Irideæ._