N. Vietnam, Bac Can prov., Na Ri distr., Kim Hy municipality, vicinities of Lung Hin Con village (N 22°17′ E 106°03′), 27 km to 55° of Bac Can city. Primary evergreen broadleaved closed forest on very steep rocky slope of karst remnant limestone ridge at elev. 550-600 m a.s.l. Forb creeping epiphytic vine up to 10 m lg. Rare.