FLORA OF VIETNAM Rubiaceae Xanthophytum polyanthum Pit.
Ha Giang prov., Quan Ba distr., Tung Vai commune, Thang village, around point 23°03ʹ04.2ʺN 104°51ʹ09.7ʺE, steep rocky slopes near mountain top composed with eroded stratified highly eroded limestone at elevation 1200-1450 m a.s.l. Primary evergreen broad-leaved very humid forest. Terrestrial and lithophytic herb 1 m tall. Very common on rocky mountain top. 24 April 2018, L. Averyanov, Nguyen Sinh Khang, Nguyen Tien Hiep, Nguyen Quang Hieu, Chuong Quang Ngan, T. Maisak, VR 809 (HN, LE01049639).