Ha Giang prov., Quan Ba distr., Bat Dai Son Nature Reserve, Thanh Van commune, Mo Sai village, around point 23°07ʹ46.4ʺN 104°57ʹ56.2ʺE, at elevation 1000-1190 m a.s.l., karstic, highly eroded mountains composed of solid marble-like limestone, primary evergreen broad-leaved and mixed (with Pseudotsuga sinensis) humid forest on steep rocky slopes near mountain tops. Woody vine to 20 m long in open place on rocky mountain slope. Flowers blue. Not common. 18 April 2018, L. Averyanov, Nguyen Sinh Khang, Chuong Quang Ngan, T. Maisak, VR 372 (HN, LE01061490, LE01067055). Det.: Sawi Mattapha 12.05.2018.