Tuyen Quang Prov., Na Hang Distr., Sinh Long Municipality, Khuoi Phin village, around point 22°38′21.9″N, 105°20′43.5″E. Primary evergreen mixed humid forest on rocky limestone on highly eroded karstic hills composed with gray solid marble-like limestone at elevation 1100-1200 m a.s.l. Lithophytic herb on vertical cliff. Flowers brightly yellow, lip with dark brown spot. Common. 29 September 2013 CPC 5319a (TM 1005 living specimen only) L.Averyanov, N.T.Hiep, L.M.Tuan, N.S.Khang, D.V.Cuong, N.V.Truong.T.Maisak, L.Osinovets Flowered in cultivation 20 May 2016. Flowers yellow, lip yellow with brown lateral marks in basal half.