N. Vietnam, Prov. Quang Binh, distr. Minh Hoa, 72 km to NWW from Dong Hoi, municipalite Thong Hoa, vicinities of Yen Son village, limestone massif Ke Bang (N 17°40′ E 105°57′). Broadleaved evergreen primary dry open forest on tops of limestone mesas at 600-650 m alt. Creeping epilitic and epiphytic woody vine up to 6-8 m lg. Flowers white. Common. VH 4757 17.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)