Luang Prabang prov., Ngoy distr., Ngoy village, Pha Noi Mountain, around point 20°42'53.6''N 102°40'34.7''E. Remnants of primary evergreen forest on very steep rocky mountain slopes composed by solid marble like highly eroded limestone at elev. 400-450 m a.s.l. Shrub to 2 m tall in open place at the mountain foothill. Flower buds whitish. Occasional.