The annuals, and most of the other species, are raised from seeds. The tuberous kinds may be increased by tubers or divisions of them. The stove and greenhouse shrubby plants may be propagated by cuttings, inserted when young in a warm frame. =Soldanella.= _Primulaceæ._ Increased by seeds and by division. =Solea.= See Ionidium. =Solidago= (Golden Rod). _Compositæ._ Seeds, sown in fall or spring, and by divisions. =Solomon's Seal.= See Polygonatum. =Sonerila.= _Melastomaceæ._ Propagated by seeds; or by cuttings which should be inserted singly in small pots during spring and placed in a frame in a propagating house. =Sophora=, including Edwardsia. _Leguminosæ._ Seeds, layers and cuttings of either ripened or growing wood. The named varieties are grafted upon common stocks. =Sorghum.= _Gramineæ._ Usually by seeds. Sometimes by cuttings as in Sugar Cane. =Sorrel= (Rumex, several species). _Polygonaceæ._ Seeds and divisions. =Sorrel-tree.= See Oxydendron. =Sour Gum.= See Nyssa. =Sowbread.= See Cyclamen. =Spanish Bayonet.= See Yucca. =Sparaxis.= _Irideæ._ Seeds. Usually by offsets. =Sparmannia.= _Tiliaceæ._ Propagated by cuttings of half-ripened wood in spring. =Spathiphyllum,= including Amomophyllum. _Aroideæ._ Propagated sometimes by seeds sown in heat, or by divisions of the root-stocks. =Spearmint= (Mentha viridis). _Labiatæ._ Commonly grown from cuttings of the creeping root-stocks. =Speedwell.= See Veronica. =Sphæralcea=, Sphæroma (Globe Mallow). _Malvaceæ._ Seeds; by cuttings of the young growth under glass, and kept shaded until rooted. =Spiderwort.= See Tradescantia. =Spinage= (_Spinacia oleracea_). _Chenopodiaceæ._ Seeds, sown usually where the crop is to stand, either in fall or spring. =Spiræa= (Spirea, Meadow-Sweet). _Rosaceæ._ Seeds, sown as soon as ripe or stratified until spring. Commonly increased by cuttings, either of mature or green wood. Green cuttings usually make the best plants. These are made in summer and handled in frames. Some sorts, as _S. ariæfolia_, _S. opulifolia_ and varieties (Nine-bark, now known as _Neillia_ or _Physocarpus opulifolia_) and _S. prunifolia_, are usually grown from layers put down in spring. The herbaceous kinds are often increased by division. =Spondias= (Hog Plum, Otaheite Apple or Plum). _Anacardiaceæ._ Seeds; by large cuttings of growing wood, which should be inserted in sand or mould, in heat. =Spruce.= See Picea and Abies. =Squash= (_Cucurbita_, three species). _Cucurbitaceæ._ Seeds, when the weather becomes warm. =Squill.= See Scilla. =Stachys=, Betonica, Galeopsis (Hedge Nettle, Woundwort). _Labiatæ._ Seeds, divisions, or cuttings. Some species (as the Crosnes or _S. tuberifera_ of recent introduction) are increased by subterranean tubers.