S.Vietnam, Thua Thien Hue Prov., Phu Loc Distr., Bach Ma National Park, Bach Ma mt, Hai Vong Dai peak, around point 16°11′46′'N 107°51′45′'E at elev. 1300-1350 m a.s.l.
Mixed and broad-leaved evergreen primary closed mt forest on steep granite slopes. Woody vine 4-5 m long with milky juice on steep open slope. Flowers white. Common.
HLF 927 18 April 2003.
Coll. V.X.Phuong, L.Averyanov, N.X.Tam, N.T.Vinh. Grant from Henry Luce Foundation.