N. Vietnam, prov. Cao Bang, distr. Bao Lac, municipality Yen Lac, vicinities of Yen Lac village (N 22°44′ E 105°50′). Primary semideciduous broadleaved forest on steep slopes and bluffs of S. exposition near the tops of remnant karst limestone ridge at 1200-1300 m elev. Herb vine up to 10 m lg. Rare.
CBL 1481 16 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)