Herbs or woody shrubs. Leaves sessile or petiolate; secondary veins 1-2. Inflorescences terminal cymes, with 1-2 dichasial branching points terminating in 2 or more monochasial branches; bracts and bracteoles scale-like or leaf-like near base of inflorescence. Flowers pedicellate, 5-merous, somewhat ventricose (flowers not seen for S. obtusisepala); calyx fused up to 2/3 of total length, coriaceous, campanulate, lobes oblong or circular, somewhat keeled, apex acute or obtuse; corolla bud apex bluntly tapering, corolla fused 1/2-2/3 of total length, thin, funnel-shaped, 90-100 mm long, deciduous in fruit; androecium zygomorphic with stamens and style bent toward bottom of corolla mouth; stamens inserted near base of corolla tube, of unequal length, filaments widened and winged at base, anthers lanceolate, with sterile apical appendage; pollen in tetrads with pilate to verrucose exine (see Nilsson, 2002); pistil with nectary disk, stigma broadly bilamellate (corolla, stamen and pistil characters not known for S. obtusisepala). Fruits a capsule, with persistent calyx and deciduous corolla; seeds angular, roughly cuboidal or conical, 0.2-0.8 mm in diam., testa cells concave with band-like thickenings.
Guyana present, Southern America: Venezuela (Venezuela present), mountain peaks on the border of Brazil and Guyana present, the tepui mountains of the western part the Guayana Highlands present
On the tepui mountains of the western part the Guayana Highlands in Venezuela and on mountain peaks on the border of Brazil and Guyana; 2 species, of which 1 species presumably in Guyana.