N.Vietnam, Thanh Hoa Prov., Ba Thuoc Distr., Thanh Son Municipality, middle part of Pu Luong range to the W of Long Bong village (20°27′52′'N, 105°07′36′'E). Primary evergreen seasonal broad-leaved closed submontane forest on basalt along main ridge at elev. 1200-1400. Lithophytic shrub with pendant shoots up to 3-6 m lg on open rocky cliff. Flowers bright red-purple. Rare, but occasionally abundant.