Vines woody. Branches terete, smooth, glabrous. Leaves simple, glabrous; petiole 1--6 cm; leaf blade elliptic, broadly elliptic, or ovate, 4.9--18 × 1.9--8.8 cm, papery, base rounded to broadly cuneate, margin entire, apex acuminate; basal veins abaxially nearly flat. Flowers solitary, terminal or axillary; peduncle ca. 0.5 mm; bracts narrowly triangular, ca. 2.5 mm. Flowers campanulate, 2--3.5 cm in diam.; pedicel 3--8.5 cm. Sepals 4, greenish yellow to yellow, erect, lanceolate, 1.2--4 × 0.5--1.3 cm, abaxially glabrous except for velutinous margin, adaxially apically appressed puberulous, apex attenuate to short cuspidate. Stamens 1.2--1.9 cm; filaments pubescent; anthers narrowly oblong, 2.6--4 mm, abaxially pubescent on connective, apex minutely apiculate. Ovaries pubescent. Style ca. 1.3 cm, densely villous. Fl. Oct--Nov.

Forests; 1600--2200 m. SE Xizang (Nyingchi Xian), NW Yunnan (Gongshan Drung-Nu Zu Zizhixian), SW Xizang [Myanmar].