Quang Binh Prov., Minh Hoa Distr., Thuong Hoa Comm., Ban On Vill., Pa Nun Valley, at point 17°40′22″N, 105°58′22″E, 250 m.
In open places of heavily logged primary, sometimes in secondary closed evergreen broad-leaved forests on foot and lower part of slopes of limestone mts.
Perennial herb; leaves 1.5-2 m tall; tooth truncate. Common.