Ha Giang prov., Quan Ba distr., Bat Dai Son commune, Bat Dai Son Nature Reserve, San Chu village, around point 23°08ʹ55.1ʺN 104°59ʹ45.7ʺE, 1000-1200 m a.s.l., karstic, highly eroded mountains composed of solid marble-like limestone, primary and partially degraded evergreen broad-leaved humid forest on rocky mountain slopes. Treelet to 4 m tall in shady place. Flowers dull reddish. Occasional. 13 April 2018, L. Averyanov, Nguyen Sinh Khang, Chuong Quang Ngan, T. Maisak, VR 071 (HN, LE01058102, LE01067146).