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′). Remnant open evergreen primary broadleaved forest along river in alluvial valley bottom between limestone ridges and mesas at 200-250 m alt. Terrestrial and epilitic herb up to 2 m hg on wet open steep rocky slope. Flowers light violet, leaves below violet. Not rare. VH 4834 19.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)