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.
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
Tachia in Hist. Pl. Guiane 1: 75. 1775 sec. by Laura Cobb, Matt Kinkade & Lena Struwe. - Tachia in JEANETTE ALLOGIO, LAURA COBB, JASON R. GRANT, MARION J. JANSEN-JACOBS, MATT KINKADE, KATHERINE B. LEPIS, HILTJE MAAS-VAN DE KAMER, PAUL J.M. MAAS, MATTHEW I. PALMER & S. MOTA DE OLIVEIRA, FLORA OF THE GUIANAS, Series A: Phanerogams Fascicle 30 139. GENTIANACEAE. 2012
- Type: Symbolanthus guianensis