N. Vietnam, Prov. Quang Binh, distr. Minh Hoa, 72 km to NWW from Dong Hoi, municipalite Thuong Hoa, Yen Son village, limestone massif Ke Bang (N 17°40′ E 105°57′). Broadleaved evergreen primary dry closed forest on steep slopes and bluffs of limestone mesas and ridges at 400 m alt. Epilitic herb on vertical shadow limestone bluffs. Not rare. Very common at 400-500 m alt. VH 4821 18.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)