Northern Vietnam, Ninh Binh Prov., Nho Quan Distr., Cuc Phuong Municipality, Cuc Phuong National Park, Dang locality, about 1 km WNW of Dang Forest Control point, 20°16′28′'N, 105°40′57′'. Secondary closed evergreen seasonal broad-leaved lowland forest on limestone hills at elev. about 400 m a.s.l. Epiphyte and lithophyte herb 15-30 cm on mossy rock outcrops near tops of hills. Flowers purple-violet. Locally common.