Hoa Binh Prov., Lac Son Distr., Ngoc Son Municipality, Khu village, around point 20°26’31”N 105°19’32”E. Primary broadleaved forest on steep rocky slopes of remnant mountain composed with solid crystalline highly eroded limestone at elevation about 550-650 m a.s.l. Creeping epiphyte on old trees on top of ridge. Not common.