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. Terrestrial herb in wet shadow stream slope. Flowers light violet, central petal with yellow base, stamens and anthers yellow. Not common. VH 4794 18.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)