N. Vietnam, prov. Cao Bang, distr. Nguyen Binh, municipality Ca Thanh, vicinities of Ta Phinh village (N 22°44′ E 105°50′). Primary closed evergreen broadleaved forest on steep slopes and bluffs of remnant karst limestone ridge at 1200-1300 m elev. Terrestrial and lithophyte herb. Flowers blue. Common.
CBL 1555 19 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)