FLORA OF VIETNAM Rubiaceae Lasyanthus sp. N.Vietnam, Ha Tinh Prov., Huong Son Distr., Son Kim Municipality, Rao Bun stream around point 18°23′39′'N, 105°15′12′'E. Primary broad-leaved evergreen closed forest on very steep mountain slopes composed with shale at elevation about 500-600 m a.s.l. Shrub 2-3 m tall. Flowers light violet. Common.