Tuyen Quang prov., Na Hang distr., Sinh Long commune, Na Tau village, around point 22°34′22″ N, 105°23′25″ E, 300 m a.s.l. In logged closed primary evergreen broad-leaved lowland forests on stream banks of limestone areas. Herb 65-75 cm tall, flower green, common. 27 Sept. 2011 N.T. Hiep, N.S. Khang, P.V. The & N.T. Vinh CPC 4509