Quang Binh Prov., Minh Hoa Distr., Thuong Hoa Comm., Ban On Vill., Pa Nun Valley, 17°40′22″N, 105°58′22″E, 250 m.
Edges or in rather open places of heavily logged primary and secondary evergreen broad-leaved forests on foot and slope of limestone mts. Leaves up to 0.6-1 m. Very common.