N. Viet Nam. Ha Giang Province, Quang Ba District, Bat dai Son. Primary forest on limestone with Biota sp., Fraxinus, Quercus, Pseudotsuga, Acer and Taxus dominants along ridge and below peak at elev. 1100-1200 m (about 23°07′N 105°02′E). Frequent lithophyte and epiphyte. Flowers all white with yellow spot at lip. DKH 5150 5 April 2000