N. Vietnam, Tuyen Quang prov., Na Hang distr., Thanh Tuong municipality, near Ban Bung village (22°16′26′'N, 105°25′58′'E). Primary wet broad-leaved evergreen forest with bamboo on very steep limestone/shale mountain slope at elev. about 500 m a.s.l. Shrublet about 1 m hg. Inflorescence white. Not rare.