Polystichum lentum (D. Don) T. Moore var. gelida Rosenstock; P. rectipinnum Hayata.

Plants evergreen. Rhizome ascending, short. Fronds 40-60 cm, nearly dimorphic, fertile fronds smaller; stipe amber, 13-23 cm, 1-1.5 mm in diam. at base, whole plant with large and small scales; all scale margins densely serrulate, teeth brown to dark brown, irregular, often forked or irregularly pinnately branched; large scales brown, ovate or ovate-lanceolate, up to 1 cm × 4 mm, thickly membranous, or middle part thickened and blackish castaneous, with broad brown margins; small scales brown to dark brown, lanceolate, apices long caudate or linear-subulate. Lamina 1-pinnate to bipinnatifid, broadly lanceolate, base slightly or not contracted, apex attenuate; sterile lamina up to 30 × 12 cm; fertile lamina up to 16 × 6 cm; rachis stramineous, abaxially densely scaly; scales brown or blackish castaneous, lanceolate or narrowly lanceolate, basiscopic margins with few long teeth; sometimes with 1 proliferous bulbil near rachis tip, bulbil densely covered with brown scales. Pinnae 8-20 pairs, green or yellowish green when dry, darker abaxially, acuminate; middle pinnae attached at right angles to rachis or slightly reflexed toward base, lanceolate, apices acuminate or acute; acroscopic base auriculate, basiscopic base cuneate, pinnatifid to pinnatilobate on both sides, margins of upper pairs of pinnae with only coarse and shallow teeth, sometimes acroscopic bases of basal 1-3 pairs of pinnae nearly pinnatisect, pinnae of sterile fronds larger, up to 6 × 1.5 cm; pinnae of fertile fronds up to 3 × 1 cm; lobes obliquely deltoid, with 1-5 acute teeth, auricles often slightly curved toward rachis; pinna midribs and abaxial surface of veins covered with numerous microscales; microscales light brown, subulate or narrowly lanceolate, membranous; frond texture thinly leathery; venation pinnate on lobes, midribs conspicuous adaxially, concave; lateral veins slightly visible abaxially, indistinct adaxially; veinlets free, veinlets on auricles dichotomous. Sori small, abaxial on veinlets, close to midrib, 1-5 on each group of lateral veins, up to 9 per auricle; indusia light brown when mature, shallowly lobed, caducous. Spores semi-orbicular in equatorial view; perispore sculpturing with finely reticulate ornamentation.

Polystichum prionolepis has special, densely serrulate scales with teeth often forked or irregularly branched pinnately. The specific epithet "prionolepis" (toothed scales) refers to this characteristic.

● On shaded rocks in montane cloud forests and Cunninghamia lanceolata forests; 2000-2400 m. Taiwan, SC Yunnan.