Description from Flora of China
Herbs. Stems twining, to 3 m, stems and petioles pubescent along 1 side. Petiole 2-6 cm; leaf blade ovate to broadly so, 7.5-16 × 3-13 cm, membranous, glabrous except for puberulent midvein, base rounded to shallow cordate, apex acute to acuminate; lateral veins 5 or 6 pairs. Cymes 2-6 cm, sometimes sessile; rachis forked or several branched, many flowered, puberulent to glabrous; cymules umbel-like. Pedicel 5-10 mm. Sepals lanceolate, ciliate; glands 5. Corolla purple, rotate; lobes broadly ovate, 2-3 × 1.5-2 mm, glabrous outside, puberulent inside. Corona lobes nearly square, apex truncate and reaching anther base. Anther appendages rounded; pollinia globose, horizontal. Stigma head discoid. Follicles lanceolate, ca. 8 cm × 8 mm, glabrous. Fl. Jun-Aug, fr. Aug-Nov.
* Forests, thickets. Fujian, Guizhou, Henan, Hubei, Hunan, Sichuan