N.Vietnam, Ha Tinh Prov., Huong Son Distr., Son Hong Municipality, around point 18°34′06′'N, 105°11′40′'E. Primary broad-leaved evergreen riparian forest with Platanus kerrii and Duabanga grandiflora along rocky river valley composed with shale and gray sandstone at elevation 250-300 m a.s.l.
Terrestrial herb up to 0.5 m tall among wet stream rocks. Flowers light pink-violet. Common.