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. Epilitic herb on vertical open bluffs. Not common, but occasionally abundant, usually on tops of mesas. VH 4760 17.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)