Vietnam, Nghe An Prov., Tuong Duong Distr., Tam Quang Municipality, Tung Huong village, along Khe Mat stream around point 19°03′26″N 104°37′22″E at elevation about 200 m a.s.l.
Lowland closed secondary evergreen forest on steep slopes along rocky stream valley composed with stratified solid shale and sandstone.
Woody vine up to 20 m long in rather open place along steep rocky shady stream slopes. Flower buds dull yellowish-green. Locally common.
HLF 6578 15 March 2007.
Coll. Averyanov L., P.K.Loc, N.V.Trai, N.T.Vinh, N.D.Phuong, Averyanova A. Grant from Henry Luce Foundation.