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 on very steep rocky slopes of karst remnant limestone ridge at elev. 300-450 m a.s.l. Terrestrial and lithophytic forb up to 0.5 m hg. Leaves below viole. Very common.