Vietnam, Quang Tri Prov., Huong Hoa Distr., Huong Viet Municipality, to N of Sa Mui pass, around point 16°51′14″N 106°34′13″E at elevation 550-650 m a.s.l.
Remnants of primary broad-leaved evergreen lowland forest on rocky remnant highly eroded solid marble-like limestone hills and low mountains with very steep slopes and vertical cliffs.
Undershrub about 1 m tall. Floral buds purple. Not common.
HLF 5944 31 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.