布朗耳蕨 bu lang er jue

Aspidium braunii Spenner, Fl. Friburg. 1: 9. 1825; Polystichum shennongense Ching, Boufford & K. H. Shing.

Plants summer-green. Rhizome erect or ascending, short, densely covered with scales; scales brown, linear. Fronds 40-70 cm; stipe brown at base, 13-21 cm, 4-5 mm in diam. at base, densely covered with scales; scales brown, linear and lanceolate or larger; large scales dense or somewhat sparse, light brown but below middle often blackish brown, shiny, ovate, ovate-lanceolate, or broadly lanceolate, up to 13 × 6 mm, subentire or slightly toothed, long acuminate or caudate. Lamina bipinnate, oblanceolate, 36-60 × 14-24 cm at middle, gradually contracted toward base, lower part sterile, apex acuminate, fertile; rachis without proliferous bulbils, abaxially with dense light brown linear or lanceolate and larger scales; large scales ovate-lanceolate, up to 4.5 mm wide, subentire, caudate or long acuminate. Pinnae 19-25 pairs, alternate, ascendant, shortly stalked, lanceolate, bases asymmetrical, apices acuminate; middle pinnae 7-15 × 2.3-2.8 cm, 1-pinnate; costa narrowly winged, abaxially with linear light brown scales. Pinnules (2-)6-17 pairs, alternate, sessile, oblong, 0.9-1.7 × 0.5-0.9 cm, bases cuneate, decurrent, acroscopic margins entire, sometimes toothed and even shallowly pinnatifid on large plants, shortly or long aristate, apices acute with acute spine; auricles rounded, small, basiscopic margins aristate; basal acroscopic pinnules largest, incised or pinnatifid; both surfaces densely scaly; microscales brownish, filiform; frond texture thinly papery; venation pinnate, lateral veins 5-7 pairs, dichotomous, distinct. Sori large, (1-)3-6 pairs per pinnule, in 1 row along each side of midrib, close to midrib, terminal or sometimes abaxial on veins; indusia present, entire. 2n = 164.

Forests, shaded or semi-shaded forest margins; 1000-3400 m. Anhui (Huangshan), S Gansu, Hebei (Dongling, Xinglong), Heilongjiang (Shangzhi), W Henan, NW Hubei, Jilin (Liangjiang, Xiaoxing’anling), Liaoning (Changbai Shan, Hengren, Kuandian), Shaanxi (Qinling), Shanxi (Ningwu, Yicheng), Sichuan (N and W basin), Xinjiang (Hejing), Xizang (Mainling) [Japan, Korea, Russia (Siberia); Europe, North America].

Fraser-Jenkins (Himalayan Ferns (Guide to Polystichum), 35. 1997) treated Polystichum shennongense as a synonym of P. makinoi, which is incorrect.

Polystichum braunii is the most widely distributed species in the genus and widely distributed in temperate regions of the N Hemisphere. It occurs in most provinces of China.