N. Vietnam, prov. Cao Bang, distr. Thach An, municipality Duc Xuan, (N 22°21′ E 106°27′), about 39 km to SSE from Cao Bang town. Secondary open shrubs on alluvial foothills of remnant limestone ridge at 400 m alt. Herb vine up to 2 m lg in open place. Common.
CBL 819 02 Dec. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)