=Sempervivum= (House-Leek). _Crassulaceæ._ Readily increased by seeds, or by the young plants which appear around the old ones at the base. =Senecio=, including Cacalia, Cineraria, Farfugium, Jacobea Kleina, Ligularia (Groundsel, Ragweed). _Compositæ._ The annuals are propagated by seeds. Others may be increased by seeds, by divisions, or by cuttings both of the roots and shoots. =Sensitive Plant.= See Mimosa. =Sequoia=, Wellingtonia (Redwood). _Coniferæ._ Seeds, which must be handled in a frame or half-shady place. Layers, and cuttings handled like those of retinospora and yew. =Sericographis.= See Justicia. =Sesamum= (Bene). _Pedaliaceæ._ Seeds, sown under glass, or in the south in the open border. =Sesbania=, including Agati (Pea-tree). _Leguminosæ._ Seeds for annual species; the shrubby kinds by cuttings of the half-ripened shoots under glass, in heat. =Shad-bush.= See Amelanchier. =Shaddock.= See Pomelo. =Shallot= (_Allium Ascalonicum_). _Liliaceæ._ Grown from "cloves," which are formed by the breaking up of the main bulb. =Shell-bark Hickory= (Shag-bark). See Hicoria. =Shepherdia= (Buffalo Berry). _Elæagnaceæ._ Increased by seeds sown in the fall or stratified until spring. =Sibbaldia.= See Potentilla. =Siberian Pea-tree.= See Caragana. =Sideritis.= _Labiatæ._ Seeds, divisions, cuttings. =Side-saddle Flower.= See Sarracenia. =Silene= (Campion, Catchfly). _Caryophylleæ._ Propagation is effected by seeds, by divisions, and by cuttings. =Silk-Cotton Tree.= See Bombax. =Silphium= (Rosin-plant, Compass-plant). _Compositæ._ Propagated by seed and by divisions. =Silver Bell.= See Halesia. =Sisyrinchium= (Blue-eyed Grass, Pig Root, Rush Lily, Satin Flower). _Irideæ._ It may be increased in spring by seeds or by divisions. =Skimmia.= _Rutaceæ._ Seeds, in a frame. Also by layers and by firm cuttings in gentle heat. =Skirret= (_Sium Sisarum_). _Umbelliferæ._ Seeds, offsets, or divisions. =Slipperwort.= See Campanula and Calceolaria. =Smilacina= (False Solomon's Seal). _Liliaceæ._ Seeds. Division of roots. =Smilax= (Green-Briar, American China Root). _Liliaceæ._ Young plants are obtained by seeds and by layers and divisions of the root. For the "Smilax" or Boston-vine of conservatories, see Myrsiphyllum. =Snapdragon.= See Antirrhinum. =Snowball-tree.= See Viburnum. =Snowberry-tree.= See Symphoricarpus. =Snowdrop.= See Galanthus. =Snowflake.= See Leucoium. =Soapwort.= See Saponaria. =Solandra.= _Solanaceæ._ Increased by seeds sown in spring; by cuttings, inserted in mould or tan. If small flowering plants are desired, the cuttings should be taken from flowering shoots. =Solanum=, including Aquartia, Nycterium (Nightshade). _Solanaceæ._