Vines woody. Branches shallowly 14-grooved, glabrous. Leaves 1- or 2-pinnate or 2-ternate, glabrous; petiole 6--10.5 cm; leaflet blades ovate to oblong-ovate, 2.5--7 × 1.2--4 cm, papery, base rounded, truncate, or subcordate, margin entire, apex acute to short acuminate; basal veins nearly flat. Cymes axillary, 7--14-flowered, often paniclelike, glabrous; peduncle 4--7.5 cm; bracts subulate, ca. 2 mm. Flowers 2--2.5 cm in diam. Pedicel 1.2--2 cm, glabrous. Sepals 4, white, spreading, oblong to obovate-oblong, ca. 8 × 4 mm, abaxially sparsely puberulous, adaxially glabrous, margin abaxially velutinous, apex acute. Stamens 6--7 mm, glabrous; anthers oblong, ca. 2 mm, apex with a conspicuous ca. 0.4 mm apicula. Ovaries glabrous. Style ca. 5 mm, densely villous. Fl. Oct--Nov.

Sparse forests, scrub; 800--1100 m. S Yunnan (Mengla Xian, Pingbian Miao Zu Zizhixian) [N Thailand].