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′). Primary evergreen open broadleaved dry forest on top of limestone mesas at 450-500 m alt. Terrestrial and epilitic herb on steep rocky slopes. Flowers white, lip white with yellow or pink center. Common. VH 4640 16.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)