S. aquatica (L.f.) Fourc.: plants 155-400 mm tall; corm smooth or rarely fibrous above. Leaves 2-5, erect, hollow, exceeding the inflorescence, linear, and ± 3 mm wide. Flowers 2-7 per scape; tepals 5-17(-35) mm long, white with green backs, often scented; bracts 2 or more, green, clasping the pedicels towards the base. Flowering June to October. In seasonal pools and streams from Namaqualand to Cape Peninsula and Swellendam.

S. capensis (L.) Garside: plants 100-350 mm tall; corm with a cap of short, fine bristles. Leaves 2-8, recurved, 3-15 mm wide, V-shaped in cross-section, distinctly keeled, margin often thickened, usually bearing minute recurved teeth. Flower 1 per scape; tepals 15-35 mm long, white, cream, yellow to orange, rarely pink, unspotted or with an iridescent or non-iridescent dark centre, backs greenish, usually lined with red; bract 1, long, green, tightly sheathing the pedicel. Flowering July to October. On seasonally wet flats from Clanwilliam to Cape Peninsula, Oudtshoorn, and western Karoo.

S. monophylla (Schltr.) Garside: small plants 20-100 mm tall; corm covered with fine, branched fibres. Leaf 1(-2), spreading, 1.5-2.0 mm wide, firm, shallowly channelled. Flower 1, on a subterranean scape; tepals 10-35 mm long, yellow with pale green backs, much longer than the stamens and style; bract 1, lance-shaped, green to whitish, clasping the pedicel towards base. Flowering December to March, especially after fire. On sandstone slopes from Kogelberg to Elim.