N. Vietnam, Thanh Hoa prov., Ba Thuoc distr., Co Lung municipality, territory of Pu Luong protected area, near Co Lung village (20°27′28′'N, 105°12′18′'E). Primary broad-leaved evergreen forest on tops of remnant highly eroded karst limestone ridge at elev. 550-600 m a.s.l. Tree 5-6 m hg . Flowers yellow-greenish. Very common. Codominante of 1 forest stratum on tops of ridge.