Son La Prov., Van Ho Distr., Xuan Nha Municipality, Pu Lau village, territory of Xuan Nha natural reserve.
Remnants of primary and secondary broad-leaved evergreen dry forest on cliffs and on very steep slopes of remnant hill composed by highly eroded stratified dark gray shale limestone at elevation 500-700 m a.s.l. around point 20°40′35.4″N 104°48′14.3″E.
Terrestrial herb to 1 m tall in wet place among secondary open shrubs along small rocky stream. Flowers blue-violet. Common.