Northern Vietnam, Ninh Binh Prov., Nho Quan Distr., Cuc Phuong Municipality, Cuc Phuong National Park, about 0.5 km W from Bong locality, 20°21′01′'N, 105°35′38′'E. Primary closed evergreen seasonal broad-leaved lowland forest on tops of limestone hills at elev. about 500 m a.s.l. Terrestrial herb on steep shady rocky slope. Occasional.