Hoa Binh Prov., Lac Son Distr., Tu Do Municipality, Mon village, around point 20°25′29”N 105°19′36”E.
Primary broadleaved forest on steep rocky slopes of remnant mountain composed with solid crystalline highly eroded limestone at elevation about 500-700 m a.s.l.
Terrestrial herb to 0.5 m tall in shady place. Flowers dull brownish-green. Common.