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, Republic of: 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.