N. Vietnam, Tuyen Quang prov., Na Hang distr., Xuan Tam municipality, near Ban Cai village (22°29′18′'N, 105°19′47′'E). Secondary open shrubs on alluvial foothills of highly eroded remnant limestone ridge at elev. 300-350 m a.s.l. Climbing shrub with shoots up to 3 m lg. Flowers yellow, fragrant. Locally very common.