察隅耳蕨 cha yu er jue

Plants summer-green. Rhizome erect, short, together with remnant stipe base up to 1 cm in diam., rhizome apex and stipe base densely scaly; scales brown, lanceolate, up to 5 mm, membranous, with few long teeth. Fronds ca. 25 cm; stipe grass-green, 6-7 cm, less than 1 mm in diam., distal stipe scales sparse, brown, narrowly lanceolate or linear, 1-2 mm, sparsely toothed. Lamina 1-pinnate, grass-green on both surfaces, adaxially darker, oblong-linear-lanceolate, up to 18 × 2-2.5 cm, apex pinnatifid and acuminate; rachis without proliferous bulbils, abaxially sparsely scaly, adaxially broadly and deeply sulcate; scales brown, clavate. Pinnae more than 25 pairs, obliquely oblong, 0.5-1.5 cm × 3-7 mm, pinnatifid to pinnatipartite, acute or obtuse, basal acroscopic margins pinnatipartite nearly to midrib and forming a pinnatilobate obovate auriculate lobe, other lobes rectangular and bilobed apically, or shortly falcate and entire on margin, primary and secondary lobes acute; abaxially sparsely covered with clavate brown microscales; frond texture thinly papery; venation pinnate on pinnae, visible abaxially, indistinct adaxially, with only 1 veinlet per primary lobe or secondary lobe. Sori terminal or abaxial on veinlets, often only 1 per lobe, sometimes 2 on basal auriculate lobes; indusia present, large, as wide as lobes, thinly membranous, dark brown when mature, centers slightly concave, coarsely lobed. Spores semicircular in equatorial view.

● Rock crevices in Picea forests; ca. 3500 m. SE Xizang (Zayü).

Polystichum zayuense is similar to P. thomsonii, but its lamina apex is shortly acuminate (vs. often linear long caudate in P. thomsonii), its ultimate segments are acute at apex (vs. mucronate), its venation is indistinct adaxially (vs. distinct and concave), and its stipe scales are all lanceolate (vs. lanceolate and ovate).