Vines woody. Branches shallowly grooved, sparsely puberulous at nodes, elsewhere glabrous. Leaves ternate; petiole 3--5 cm, adaxially puberulous; leaflet blades ovate, 3.6--10 × 2--5 cm, papery, both surfaces sparsely puberulous, base rounded or subcordate, margin irregularly dentate, apex acuminate; basal veins abaxially slightly prominent. Cymes axillary, 1--3-flowered; peduncle 0.9--1.6 cm, subglabrous; bracts linear, 6--12 mm. Flowers ca. 1 cm in diam.; pedicel 2--3 cm, subglabrous. Sepals 4, purple, erect, oblong or lanceolate, ca. 16 × 5 mm, abaxially sparsely puberlous near base and apex, adaxially glabrous, margin velutinous, apex obtuse. Stamens slightly shorter than or equaling sepals; filaments densely villous; anthers narrowly oblong, ca. 2.2 mm, abaxially villous on connective, apex obtuse. Ovaries puberulous; style ca. 8 mm, densely villous. Fl. Sep.

* Forests; ca. 800 m. W Anhui (Jinzhai Xian).