Vietnam, Dac Lac Prov., Buon Don Distr., Krong Na municipality, Yok Don national park, around point 12º51’27”N 107º41’52”E. Open dry semi-deciduous Dipterocarpus forest on thin ferralite gray soils at elevation about 200 m a.s.l. along Srepok river valley. Epiphyte on Dipterocarpaceae trees. Flowers purple-violet. Common. HLF 7339 23 March 2008 photo Coll. N.T.Hiep, Averyanov L., P.K.Loc, N.T.Vinh, N.S.Khang, T.H.Thai, N.V.Trai