N. Vietnam, Thai Nguyen prov., Vo Nhai distr., Than Sa municipality, vicinities of Kim Son village (N 21°48′ E 105°54′), 23.3 km to 18° of Thai Nguyen city. Secondary open broadleaved forest and shrubs on very steep rocky slopes of remnant karst limestone ridge at elev. about 100 m a.s.l. Terrestrial forb up to 1 m hg in open place. Flowers white. Common.