N.Vietnam, Ha Tinh Prov., Huong Son Distr., Son Hong Municipality, around point 18є34'06''N, 105є11'40''E. Primary broad-leaved dry closed evergreen forest on very steep mt slopes of Khe Sinh stream canyon and along ridge composed with shale at elev. 800-1100 m a.s.l. near Laotian border. Terrestrial creeping herb on steep shady slope. Flowers: tepals light brown, lip light yellow with purple marks. Occasional.