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 broadleaved forest on steep slopes and bluffs of limestone mesas at 200-250 m alt. Terrestrial and epilite herb on shadow steep slope. Flowers white. Very common. VH 4594 15.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)