Description from Flora of China
Aspidium formosanum Christ, Bull. Herb. Boissier, sér. 2, 4: 615. 1904; Dryopteris constantissima (Hayata) Hayata; D. kodamai Hayata; D. liui Ching; D. phaeolepis Hayata; Polystichum constantissimum Hayata; P. varium (Linnaeus) C. Presl var. eurylepidotum Rosenstock.
Rhizome ascending, apex densely covered with castaneous, lanceolate scales. Fronds caespitose. Stipes stramineous, 25-35 cm, ca. 2 mm in diam., densely covered with castaneous, lanceolate 1-1.2 cm × ca. 2 mm, entire scales at base. Lamina pentagonal, 20-30 × 20-25 cm, deeply cordate, tripinnate, pinnatifid at apex. Pinnae 8-10 pairs, broadly lanceolate, 10-15 cm, widest at base, up to 10 cm wide. Pinnules ca. 10 pairs, those on basiscopic side usually longer than those on acroscopic side, lowest basiscopic pinnule on lowest pinna much longer than next pinnule and directed downward. Ultimate pinnules on lowest basiscopic pinnule 8-10 pairs, oblong, 1-1.5 cm × 4-5 mm, with sharp teeth, obtuse at apex. Veins obscure on both surfaces. Lamina papery, green; rachis and pinna rachis densely covered with scales; scales on rachis nearly black, lanceolate; scales on pinna rachis light brown, saccate. Sori on either side of costa; indusia brown, entire. n = 123.
Subtropical broad-leaved evergreen forests, warm-temperate forests; 900-2900 m (in Taiwan). Sichuan, Taiwan, Zhejiang [Japan].