Ha Giang Prov., Quan Ba Distr., Tung Vai Commune, Thang Village, around point 23.05349°N 104.86446°E, steep rocky slopes of river valley composed with eroded limestone mixed with sandstone at elevation 1000–1100 m a.s.l. Remnants of primary evergreen broad-leaved very humid forest along river. Woody fern about 2 m tall on steep shady slope. Common. 7 October 2019, L. Averyanov, Nguyen Sinh Khang, T. Maisak, VR 1434 (HN, LE01061052, LE01066980).