N.Vietnam, Thanh Hoa Prov., Ba Thuoc Distr., Thanh Son Municipality, middle part of Pu Luong range around point 20º28'14''N, 105º05'34''E. Primary evergreen seasonal broad-leaved closed submontane forest on basalt along main ridge at elev. 1450-1550 m. Epiphyte. Flowers: tepals dull yellowish with numerous reddish-purple marks, lip reddish-purple. Rare.