Hoa Binh Prov., Lac Son Distr., Ngoc Son Municipality, Khu village, around point 20°26′31”N 105°19′32”E. Primary broadleaved forest on steep rocky slopes of remnant mountain composed with solid crystalline highly eroded limestone at elevation about 550-650 m a.s.l. Epiphyte on old trees on top of ridge. Not common. CPC 1627 27 March 2011 Coll.: N.Q.Hieu, L.Averyanov, N.T.Hiep, P.K.Loc, P.V.The, N.T.Vinh, T.B.Ngan, N.Tap, D.D.Dao, V.T.Ha. Fl. in cult. 6 Oct. 2015. Flowers white, lip purple along margin in basal part. L. Averyanov.