Vietnam, Quang Tri Prov., Huong Hoa Distr., Huong Phung Municipality, Sa Mui pass, around point 16°48′36″N 106°34′44″E at elevation about 1300-1400 m a.s.l.
Primary and secondary broad-leaved evergreen submontane forest on very steep rocky shale southern slopes of Sa Mui Mountain.
Undershrub 0.5-1 m tall along ridge edge. Flowers light violet. Very common.
HLF 5865 29 March 2006.
Coll. N.T.Hiep, L.Averyanov, P.K.Loc, P.V.The, N.S.Khang, P.H.Duc, L.T.Son, S.Bounphanmy, T.K.Ratana, O.Sonliya, T.Q.Dang, N.V.Hien, H.T.N.Trang, L.T.Chau. Grant from Henry Luce Foundation.