Tuyen Quang Prov., Na Hang Distr., Sinh Long municipality, centre of Nam Duong village, around point 22°35′07″N, 105°22′14″E, 344 m. In completely logged closed primary evergreen broad-leaved lowland forests on stream banks of limestone areas. Dominant lithophyte along streams. Undershrub, 1-2 m tall; flowers greenish.
CPC 1333 13 March 2011 Coll.: N.Q.Hieu, N.T.Hiep, P.K.Loc, N.T.Vinh