Vietnam, Thua Thien – Hue Prov., Nam Dong Distr., Huong Son Municipality, around point 16°09'58''N, 107°36'07''E. Fractionally logged primary closed broad-leaved evergreen lowland forest along La Ma River on very steep hill slopes composed with clayey shale and sandstone at elevation 300-400 m a.s.l. Lithophytic and terrestrial herb on rocky steep hill slope. Flowers light blue. Locally common.