199. Polystichum subacutidens Ching ex L. L. Xiang, Acta Phytotax. Sin. 32: 261. 1994.
多羽耳蕨 duo yu er jue
Polystichum deltodon (Baker) Diels var. cultratum Christ.
Plants evergreen. Rhizome erect, short, together with stipe base 1.5-3 cm in diam., rhizome apex densely scaly; scales shiny, yellowish brown, linear-lanceolate, ca. 1.5 cm × 1-1.5 mm, thickly membranous, entire. Fronds 35-60 cm; stipe light stramineous or greenish stramineous, 4-15 cm, 1-1.5 mm in diam., lower part densely scaly; scales yellowish brown to dark brown, ovate-lanceolate, up to 1 cm × ca. 3 mm, thickly membranous, finely toothed, appressed or opening in upper part; scales gradually sparser toward lamina apex, mixed with membranous and thinly membranous scales; scales appressed, ovate-lanceolate, lanceolate, narrowly lanceolate, or broadly ovate, sulcate, varying in size, margins erose to nearly fimbriate, bases of partial scales peltate. Lamina 1-pinnate, green or yellowish green when dry on both surfaces, narrowly elliptic-lanceolate, 25-50 × 1.8-3 cm at middle, often gradually contracted below middle of lamina, 1-1.5 cm wide at base, acuminate; rachis green or pale greenish stramineous, without proliferous bulbils, with denser small scales adaxially; small scales brown, filiform, evanescent. Pinnae 40-110 pairs, alternate or nearly opposite, sessile or shortly stalked, attached at right angles with rachis or upper pairs sometimes slightly angled acroscopically, basal one to several pairs or sometimes upper pairs above middle of lamina ± reflexed, oblong-deltoid or right triangular, 7-15 × 3-5 mm at middle, apices obtuse-rounded or acute, bases asymmetrical, acroscopic base auriculate; auricles deltoid with acute tips, proximal margins of auricles truncate or slightly curved outward, parallel to rachis, acroscopic margins of pinnae repand to coarsely crenate, rarely pinnatilobate with acute lobes, basal basiscopic margins narrowly cuneate, straight or slightly recurved, margins entire, distal basiscopic margins weakly repand or with 2 or 3 coarse obtuse teeth; adaxially glabrous, abaxially sparsely covered with linear light brown microscales; frond texture papery; venation pinnate, distinct abaxially, slightly visible adaxially; all lateral veins ending short of pinna margin, pinnate above midrib from base to apex, dichotomous or simple, simple or dichotomous below midrib. Sori small, terminal on shorter veinlets, close to pinna margin; indusia present, light brown, darker at center, entire, caducous. Spores orbicular in equatorial view; perispore sculpturing plicate.
Limestone crevices in montane broad-leaved evergreen forests, limestone caves; 700-1500 m. S Guizhou (Changshun, Ziyun), NW Guangxi (Leye, Nandan), SE Yunnan [N Vietnam].
Polystichum subacutidens has a narrow, long lamina with up to 110 pairs of pinnae.