N. Vietnam, Hoa Binh prov., Da Bac distr., to the SW of Doan Ket village (20°54′01′'N, 105°04′19′'E). Primary broad-leaved evergreen forest with Calocedrus rupestris (?) along tops of remnant highly eroded limestone ridge at elev. 900-1000 m a.s.l. Lithophyte woody vine 4-6 m lg in open mossy rocks. Not common.