FLORA OF VIETNAM. Orchidaceae. Acampe rigida (Buch.-Ham. ex Sm.) P.F.Hunt. Dien Bien Prov., Tua Chua Distr., Ta Phin Municipality, around point 22°00'21"N 103°21'39"E. Open secondary scrub on very steep rocky humid mossy slopes of remnant hills composed with highly eroded marble-like solid crystalline limestone at elevation about 1150 m a.s.l. Lithophytic undershrub to 1 m tall on open mossy rocks. Not common. CPC 1010 16 December 2010. Coll.: L.Averyanov, P.K.Loc, P.V.The, N.T.Vinh.