Herbs, subshrubs, shrubs to small trees. Leaves sessile to petiolate, 1.5-29 cm long; ca. 5-veined. Inflorescences terminal, dichasial with monochasial branches, sometimes flowers solitary; bracts and bracteoles absent/scale-like/leaf-like. Flowers pedicillate, 5-merous, actinomorphic or slightly zygomorphic; calyx fused at base for ca. 1/10 (seldom more) of length, coriaceous, campanulate to tubular; lobes lanceolate, elliptic to ovate, dorsally thickened, often glandular, rarely with keels; apex obtuse to acute; corolla fused at base, salver-shaped to funnel-shaped, 28-110 mm long; corolla bud apex tapering, androecium zygomorphic with stamens and style bent towards bottom of corolla mouth; stamens inserted in corolla tube in lower quarter, of unequal length, base of filaments fused with corolla into a ring-shaped corona, or with flaps of tissue between filament bases, anthers linear, connective apex apiculate; pollen in tetrads; pistil with nectary disk around base, stigma bilamellate. Fruit a capsule, sometimes indehiscent(?), with persistent calyx and deciduous corolla; seeds angular, testa pattern dome-like, sometimes with band-like thickenings.
Guyana present present, Southern America: Bolivia (Bolivia present); Brazil North (Amazonas present); Colombia (Colombia present); Costa Rica (Costa Rica present); Ecuador (Ecuador present); Panamá (Panamá present); Peru (Peru present); Venezuela (Venezuela present)
A neotropical genus of ca. 38 species from Costa Rica, Panama, Colombia, Ecuador, Peru, Bolivia, Venezuela, Guyana and Brazil (Amazonas); 1 species in Guyana.