N. Vietnam, prov. Cao Bang, distr. Nguyen Binh, municipality Ca Thanh (N 22°44′ E 105°50′). Primary semideciduous broad-leaved forest on steep slopes and bluffs of remnant karst limestone ridge at 1250-1300 m elev. Shrub up to 2 m hg. Flowers blue. Very common. Codominante of shrublet forest stratum in shady places, especially near tops of ridge.
CBL 1263 13 April 1999
International Botanical Expedition of the U.S.A. National Geographic