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. Epiphyte on high trees. Flowers white, lip with pink nerves. Very common on tops of mesas. VH 4639 16.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)