Cao Bang Prov., Bao Lac Distr., Dinh Phung municipality, Ban O village. Primary mixed and coniferous evergreen humid forest with (Pinus sp., Pseudotsuga sinensis, Podocarpus neriifolius) on very steep slopes and on mountain tops composed by solid highly eroded limestone at elevation 1200-1300 m a.s.l. around point 22°45′24.8″N 105°46′47.9″E. Epiphytic and lithophytic herb on steep rocky slope near mountain top. Common. 24 November 2014 CPC 7640a Coll.: L.Averyanov, N.T.Hiep, N.S.Khang, T.Maisak, L.Osinovetz
Flowered in 20 June 2017, flowers dull light yellowish, lip yellow tinged with purple near margin. L. Averyanov. Photos.