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. Lithophytic fern on shady cliff. Near mountain top. Very rare. 24 April 2018, L. Averyanov, Nguyen Sinh Khang, Nguyen Tien Hiep, Nguyen Quang Hieu, Chuong Quang Ngan, T. Maisak, VR 854 (holotype – LE01049764, isotype – HN). Unusual plant, which differs from known species in dwarf habit, simple ovate or inequally-deltoid undissected lamina and exindusiate sori placed in one row parallel to the lamina margin. Curiously resembles juvenile plantlets of C. hemionitis, with which in locus classicus grows together.