Sepals five, quincuncially imbricate, free or rarely united at the extreme base, mostly ovate, ovate-lanceolate, broadly lanceolate orbicular, or oblong-orbicular, equal or unequal, acute, acuminate, obtuse, rounded or slightly emarginated at the apex, sericeous, tomentose, pilose, velutinous, ferrugineous or glabrous on the inner surface, persistent in capsules. Corolla white, blue, bluish purple, pink or red, yellow, yellowish white or greenish white, funnel-shaped, petalous with entire, subentire, lobed or lobulate limb, outside sparsely or densely pilose on interplicae (midpetaline bands), glabrous on plicae (infolded areas); individual hairs on interplicae with two unequal arms (long arms directed toward apices of petals). Stamens five, alternate with petals, inserted or rarely exserted, all fertile; filaments epipetalous (being adnate to the lower, narrow part of the corolla), straight, filiform or somewhat dilated below, dorsiventrally flattened, unequal, subequal or equal in length, glabrous or thinly to densely villous or glandular-villous (with crisped or curly hairs), frequently villous only on the basal dilated portions; anthers two-celled, oblong or oblong-lanceolate, dorsifixed or apparently basifixed, frequently sagittate or cordate at the base, introrse or partially extrorse by vertically dehiscing slits; pollen colpate and punctitegillate, not spiniferous. Ovary superior, bi carpellate, bilocular, long-pilose or hirsute with two-armed hairs (both arms of each hair directing toward the mouth of the corolla) or glabrous, surrounded by annular disc at the base; ovules two in each loculus, erect, anatropous, in axile placentation, appearing to be basal; styles terminal, two, almost free to partially united, included in the corolla to partially exserted; stylar branches (or stylodia) equal to unequal, filiform, mostly glabrous, occasionally with scattered hairs; stigmas large or small, globose, subglobose, capitate, reniform, bilobed conical or rarely peltate, smooth or rugose, occasionally lobulate.
Well characterised by its gynoecium and fruit, apparently convergent with the Indochinese genus Cordisepalum Verdc. The pollen difference between the 2 genera is distinctive.