Shrubs, small trees, to perennial herbs. Leaves petiolate to subsessile, 6.5-35 cm long; 3-11-veined. Inflorescences axillary, flowers solitary or 2 together from small cushion; bracts and bracteoles absent. Flowers sessile, 5-merous, actinomorphic to zygomorphic; calyx fused at base for 1/2-9/10 of length, coriaceous, campanulate or tubular, lobes ovate, triangular or elliptic, dorsally thickened, sometimes with dorsal keel, apex obtuse, acute, or acuminate; corolla fused into corolla tube, membranacous, salver-shaped or funnel-shaped, 14-95 mm long; corolla bud apex tapering; androecium zygomorphic with stamens and style bent towards bottom of corolla mouth; stamens inserted in corolla tube close to base, of unequal length, base of filaments without appendages, anthers oblong, connective apex with small sterile tip; pollen in monads; pistil with nectary disk around base, stigma bilamellate. Fruit a woody capsule, with late-deciduous calyx and deciduous corolla; seeds globose to angular, testa papillate.
Guianas: present Neotropics: present
13 species in the Neotropics; 4 (5?) in the Guianas.
Tachia is derived from the Galibi Indian name for ants' nest "tachi". Ants live in the hollow stems and branches (Aublet 1775).
The type specimen of