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. Primary broadleaved evergreen dry forest along tops of karst remnant limestone ridge at elev. 450-550 m a.s.l. Epiphytic and lithophytic creeping vine 10-20 cm hg. Abundant.