N. Vietnam, prov. Cao Bang, distr. Bao Lac, municipality Yen Lac, vicinities of Yen Lac village (N 22°44′ E 105°50′). Secondary wet broadleaved evergreen forest in deep shady limestone ridge canyon along stream at about 1000 m elev. Herb vine up to 4 m lg. in open place. Common.
CBL 1433 16 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)