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 dry evergreen broadleaved forest with bamboo on tops of remnant karst limestone ridge at elev. 250-300 m a.s.l. Lithophyte forb up to 0.2 m hg on open rocks. Very common.