Son La Prov., Van Ho Distr., Van Ho comm., Hua Tat village, around point 20°46’21.7N 104°47’47.5E. Remnants of primary evergreen broad-leaved and mixed forest (with Pinus wangii) on very steep rocky slopes and on mountain tops composed with highly eroded karstic light gray marble-like limestone at elevation 1300-1350 m a.s.l. Terrestrial herb on steep wet open slope. Flowers white. Locally common.