N. Vietnam, Prov. Cao Bang, Distr. Tra Linh, Subdistr. Quoc Toan, evergreen forest on slopes of remnant limestone mountains near Thang Heng lake in environs of Thang Hen and Lung Tao villages.
Climbing shrub or vine up to 4 m lg. Flowers yellowish-violet. Very common at 600-650 m alt., especially in wet places in secondary associations.
VH 2470 04.01.1996
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5094-93)
Participants: L. Averyanov, N.T. Ban, A. Budantzev, L. Budantzev, N.T. Hiep, D.D. Huyen, P.K. Loc, G. Yakovlev