Quang Binh Prov., Minh Hoa Distr., Thuong Hoa municipality, around point 17°41’28”N 105°53’42.7”E. Wet primary evergreen broad-leaved forest on shady humid rocky slope of narrow stream canyon composed with solid crystalline limestone at elevation about 600 m a.s.l. Undershrub about 1 m tall in open places. Occasional.