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′). Remnant open evergreen primary broadleaved forest along river in alluvial valley bottom between limestone ridges and mesas at 200 m alt. Prostrate herb in wet places. Common. VH 4717 17.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)