Ha Giang prov., Quan Ba distr., Tung Vai commune, Thang village, around point 23°03ʹ13.4ʺN 104°51ʹ48.8ʺE, steep rocky slopes of stream valley composed with eroded stratified highly eroded limestone at elevation 1000-1200 m a.s.l. Primary evergreen broad-leaved very humid forest. Woody fern to 10 m tall and fronds to 4 m long on steep rocky slope. Very common. 23 April 2018, L. Averyanov, Nguyen Sinh Khang, Nguyen Tien Hiep, Nguyen Quang Hieu, Chuong Quang Ngan, T. Maisak, VR 727 (HN, LE01050092).