Description from Flora of China
Drynaria costulisora Ching & S. K. Wu; D. rivalis (Mettenius ex Baker) Christ; D. tibetica Ching & S. K. Wu; Polypodium rivale Mettenius ex Baker.
Rhizome creeping, 0.5-1(-2) cm in diam.; scales soft, tufted, basifixed, 5-11 × 0.5-1.2 mm, margin biserrate; fronds dimorphic, hairy; basal fronds sessile, 7-15 × 3-7 cm, base cordate, auriculate, pinnatilobed up to 2/3 or more, lobes 8-13 pairs, margin entire, ciliate at young stage, glabrous on both sides, lower side of costa slightly hairy and with small scales at base; foliage fronds stalked, stipe 1-3(-13) cm, conspicuously winged; lamina pinnatifid up to 0-2 mm from costa, 20-40(-50) × 7-12(-15) cm, apex not aborted; pinnae 15-18 pairs, spreading, lanceolate, 3-8 × 1-1.5(-2) cm, margin entire, densely ciliate, apex obtuse; abaxial side along costa with small scales. Sori in 1 straight row between costa and margin, 1 row between lateral veins. Spores with spines.
Epilithic on limestone rocks in Quercus forests, or on tree trunks in mixed forests; 2700-3400 m. Xizang, NW Yunnan [Bhutan, N India, Nepal].