Stems spirally twisted, twining, terete. Petiole 1-3 cm; leaf blade lanceolate, ovate-lanceolate, or ovate, 4-7 × 2-3.5 cm, base rounded to truncate, margin crenulate, apex acuminate, veins 3. Inflorescences 1flowered or cymes; bracts 1-4 pairs, usually leafy, ovate to triangular. Pedicel 2-3 mm. Calyx campanulate; tube 7-9 mm, winged; lobes subulate to linear, 0.9-1.5 cm, apex acuminate. Corolla white, occasionally tinged purple outside, narrowly campanulate, 4-4.2 cm; lobes triangular, 4-5 mm, apex acuminate; plicae obliquely triangular, 1-2.5 mm, margin crenulate. Filaments linear, 1-2 cm; anthers ellipsoid, 1-2 mm. Disc 1-1.5 mm. Ovary 1-1.5 cm; gynophore 2-3 mm. Style linear, 1.5-2.5 cm. Berries dark purple, ellipsoid, 2-3.5 cm × 4-7 mm; gynophore 1-3 mm. Seeds dark purple, ellipsoid to ovoid, triquetrous, 1.5-2 mm, wingless.