疏羽耳蕨 shu yu er jue

Plants evergreen. Rhizome erect, densely scaly; scales dark brown, narrowly lanceolate, up to 1.5 cm, only apical margins serrulate, subentire below apex. Fronds up to 1.5 m; stipe up to > 50 cm, up to 4 mm in diam. at base, basal stipe densely scaly; scales dimorphic (large and small), upper part only with few small scales; large scales dark brown or middle part castaneous and margins brown, broadly lanceolate to lanceolate, curved, up to 2 cm × 4 mm, or middle part thickened, with broad margins, margins membranous, upper margins serrulate, subentire below apex; small scales light brown at base, castaneous upward, narrowly lanceolate, or subulate-lanceolate to subulate-linear, bases broadly rounded. Lamina bipinnate, green or light green when dry, adaxially darker, ovate-lanceolate or narrowly deltoid, up to 60 × 30 cm, base slightly or not contracted, apex abruptly slightly contracted, attenuate; rachis and costa stramineous, abaxially covered with numerous small scales; small scales brown to castaneous, subulate-lanceolate to subulate-linear, persistent; rachis with 1 or 2 proliferous bulbils near tip, bulbils densely covered with lanceolate and brown small scales. Pinnae up to 20 pairs, slightly ascendant, or sometimes basal pairs attached at right angles to rachis, alternate or nearly opposite, approximate, apical pairs obliquely ovate-lanceolate to obliquely ovate, pinnatipartite to pinnatilobate, apex acute; other pairs lanceolate or oblong-falcate-lanceolate, up to 18 × 4 cm, bases slightly or not contracted, pinnate, apices pinnatifid-acuminate. Pinnules up to 15 pairs, connected or approximate, alternate or opposite, slightly ascendant, obliquely ovate, up to 2 × 1 cm at middle, apices slightly curved acroscopically, acute, spinulose; acroscopic bases truncate, slightly auriculate, parallel with rachis, basiscopic side curved, margins sparsely incised, often spinulose on upper part; abaxially densely scaly; microscales brown to dark brown, linear; frond texture papery; venation bipinnate, abaxially visible, slightly raised, adaxially slightly visible, midrib obviously concave, veinlets ascendant, nearly reaching pinnule margins. Sori terminal on shorter veinlets, medial or close to pinnule margins; indusia present, entire, centers concave and shallowly funnelform when mature, light brown. Spores semi-orbicular in equatorial view; perispore sculpturing thin, shallowly reticulate.

Montane broad-leaved evergreen forests; 1100-2100 m. W Guangxi, Yunnan [N Vietnam].

Polystichum disjunctum mostly resembles P. biaristatum but has 1 or 2 proliferous bulbils near the rachis tip.