Description from Flora of China
Polystichum pseudorhomboideum H. S. Kung & Li Bing Zhang, nom. illeg. superfl.
Plants evergreen. Rhizome erect, densely covered with lanceolate brown scales. Fronds 10-18 cm; stipe stramineous, 4-8 cm, 1-2 mm in diam. at base, scaly; scales light brown, ovate and filiform. Lamina lanceolate or linear-lanceolate, 6-12 × 2-3 cm, not or slightly contracted at base, 1-pinnate, sometimes with 1 lobe on acroscopic bases of basal pinnae only, acuminate; rachis without proliferous bulbils, abaxially scaly; scales narrow, margins ciliate. Pinnae 8-16 pairs, alternate, attached at right angles to rachis, ovate or nearly deltoid, 1-1.8 × 0.8-1.4 cm, bases broadly cuneate or obliquely broadly cuneate, acroscopic bases auriculate, shortly stalked, margins spinulose-toothed, often with 1 or 2 lobes on acroscopic base, sometimes with free pinnules, apices nearly rounded and mucronate; lobes obovate or rhombic, obtuse and mucronate at apex; abaxially scaly; microscales filiform, strongly ciliate at base; frond texture leathery; venation pinnate on pinnae, slightly raised on both surfaces. Sori in 1 row on each side of midrib; indusia present, toothed.
Polystichum pseudorhomboideum is a nomen novum replacing P. rhomboideum Ching, but it was nomenclaturally superfluous when published because the supposed earlier homonym, "Polystichum rhomboideum Schott" (Gen. Fil. ad t. 9. 1834), is a nomen nudum and was not therefore validly published (Melbourne Code, Art. 38.1(a)).
Polystichum rhomboideum does not occur in Yunnan.
Fraser-Jenkins (Himalayan Ferns (Guide to Polystichum), 28. 1997) treated Polystichum rhomboideum as a synonym of P. cyclolobum.
● On rocks; 1800-2000 m. S Gansu (Zhouqu), W Sichuan (Leibo).