N.Vietnam, Thanh Hoa Prov., Ba Thuoc Distr., Thanh Son Municipality, Bang village, E macroslope of Pu Luong range around point 20°27′34′'N, 105°07′17′'E at elev. 700 m a.s.l. Secondary evergreen shrubs on shale soil at edge of forest. Herbaceous vine up to 20 m lg. Flowers white. Rare.