Stems spirally twisted, twining, terete, striate. Petiole 1.5-2 cm, slender; leaf blade ovate-lanceolate to ovate, 4-6 × 3-4 cm, base cordate, margin crenulate, apex acuminate, veins 3. Flowers solitary; bracts 1-3 pairs, lanceolate, ca. 5 mm. Pedicel 2-3 mm. Calyx subcampanulate; tube 6-8 mm, winged; lobes linear to linear-lanceolate, 5-9 mm, apex acuminate. Corolla white, narrowly campanulate, 3.5-4 cm; lobes ovate-triangular, 4.5-5 mm, apex acute; plicae semiorbicular, 1-1.5 mm, margin erose. Filaments linear, 1.2-1.6 cm; anthers ellipsoid, 1.5-2 mm. Disc ca. 1.5 mm. Ovary subsessile, 7-10 mm. Style linear, 2-2.5 cm. Berries ovoid. Seeds compressed, discoid, narrowly winged. Fl. Sep.

* Forests; 500-1300 m. Sichuan, Yunnan.