Rudbeckia.—Bold-habited composite plants, well suited for shrubbery borders, and thriving in light loamy soil. The flower-heads have a dark-coloured elevated disk. R. Drummondii, 2 to 3 ft., with the ray-florets reflexed, yellow at the tip and purplish-brown towards the base; R. fulgida, 2 ft. golden-yellow with dark chocolate disk, the flower-heads 2 to 3 in. across; and R. speciosa, 2 to 3 ft., orange-yellow with blackish-purple disk, the flower-heads 3 to 4 in. across, are showy plants.
Sagittaria.—Graceful water or marsh plants with hastate leaves, and tuberous, running and fibrous roots. S. japonica plena; S. lancifolia, S. macrophylla and S. sagittifolia, are among the best kinds, all with white flowers.
Salvia.—The Sage, a large genus of labiates, often very handsome, but sometimes too tender for English winters. S. Sclarea, 5 to 6 ft., is a very striking plant little more than a biennial, with branched panicles of bluish flowers issuing from rosy-coloured bracts; S. patens, 2 ft., which is intense azure, has tuberous roots, and may be taken up, stored away and replanted in spring like a dahlia. S. pratensis, 2 ft., blue, a showy native species, is quite hardy; the variety lupinoides has the centre of the lower lip white.
Saxifraga.—A very large genus of rock and border plants of easy culture. The Megasea group, to which S. ligulata, S. cordifolia and S. crassifolia belong, are early-flowering kinds of great beauty, with fleshy leaves and large cymose clusters of flowers of various shades of rose, red and purple. Another very distinct group with silvery foliage—the crustaceous group—contains some of our choicest Alpines. Of these S. caesia, S. calyciflora, S. Cotyledon are among the best known. Some of the species look more like lichens than flowering plants. The green moss-like saxifrages are also a very distinct group, with dense tufted leaves which appear greener in winter than in summer. The flowers are borne on erect branching stems and are chiefly white in colour. Saxifraga umbrosa (London Pride) and S. Geum belong to still another group, and are valuable alike on border and rockery. S. peltata is unique owing to its large peltate leaves, often 1 ft. to 18 in. across, with stalks 1 to 2 ft. long. Flowers in April, white or pinkish. Likes plenty of water and a moist peaty soil or marshy place. S. sarmentosa, the well-known “mother of thousands,” is often grown as a pot plant in cottagers’ windows.
Scilla.—Beautiful dwarf bulbous plants, thriving in well-worked sandy loam, or sandy peat. S. bifolia, 3 in., and S. sibirica, 4 in., both intense blue, are among the most charming of early spring flowers; S. patula, 6 to 8 in., and S. campanulata, 1 ft., with tubular greyish-blue flowers, freely produced, are fine border plants, as is the later-blooming S. peruviana, 6 to 8 in., dark blue or white.
Sedum.—Pretty succulent plants of easy growth, and mostly suitable for rockwork. They are numerous, varied in the colour of both leaves and foliage, and mostly of compact tufted growth. S. spectabile, 1 to 1½ ft., pink, in great cymose heads, is a fine plant for the borders, and worthy also of pot-culture for greenhouse decoration. Mention may also be made of the common S. acre (Stonecrop), 3 in., yellow, and its variety with yellow-tipped leaves.
Sempervivum.—House-Leek. Neat-growing, succulent plants, forming rosettes of fleshy leaves close to the ground, and rapidly increasing by runner-like offsets; they are well adapted for rockwork, and do best in sandy soil. The flowers are stellate, cymose, on stems rising from the heart of the leafy rosettes. S. arachnoideum, purplish, S. arenarium, yellow, S. globiferum and S. Laggeri, rose, grow when in flower 3 to 6 in. high; S. calcareum, rose colour, and S. Boutignianum, pale rose, both have glaucous leaves tipped with purple; S. Heuffelii, yellow, with deep chocolate leaves, and S. Wulfeni, sulphur-yellow, are from 8 to 12 in. high.
Senecio.—A large genus with comparatively few good garden plants. Large and coarse-growing kinds like S. Doria, S. macrophyllus and S. sarracenicus are good for rough places; all yellow-flowered. S. pulcher is a charming plant, 2 to 3 ft. high, with rosy-purple flower-heads, having a bright orange centre. It likes a warm corner and moist soil. S. clivorum, from China, has large roundish leaves and orange-yellow flowers. It flourishes near water and in damp places.
Shortia.—S. galacifolia, a beautiful tufted plant 2 to 3 in. high, with roundish crenate leaves, on long stalks, and white funnel-shaped flowers in March and April. S. uniflora from Japan is closely related. The leaves of both assume rich purple-red tints in autumn. Warm sunny situations and rich sandy loam and peat are required.
Silene.—Pretty caryophyllaceous plants, preferring sandy loam, and well adapted for rockwork. S. alpestris, 6 in., white, and S. quadridentata, 4 in., white, are beautiful tufted plants for rockwork or the front parts of borders; S. maritima flore-pleno, 6 in., white, S. Elizabethae, 4 in., bright rose, and S. Schafta, 6 in., purplish-rose, are also good kinds.