中锡蹄盖蕨 zhong xi ti gai jue

Rhizomes short, erect, apex densely clothed with dark brown, narrowly lanceolate scales. Fronds caespitose; fertile fronds (12-)75-100 cm; stipe stramineous, 4-32 cm, 1-3.6 mm in diam., base similarly densely scaly, upward sparsely scaly; lamina pinnate-pinnatipartite to 2-pinnate, oblong, 12-40 (-60) × 5-23(-32) cm at middle, base hardly narrowed, apex acuminate and pinnatifid; pinnae 10-18 pairs, basal 2-4 pairs opposite, separated from each other, upper pinnae alternate, spreading, sessile; basal pinnae slightly shortened, (1.5-)9-10 cm, slightly narrowed at base, reflexed; middle pinnae lanceolate, up to 12-16 × 2-3 cm, base equilateral, truncate, slightly broadened, pinnatipartite nearly to costae, apex acuminate and toothed; pinnules (or pinna segments) up to 24 pairs, usually deltoid-oblong, basal pinnules longer, ca. 1 cm × 3.5 mm, connate with each other by narrow wing of costa, dentate at margin, apex subacute to acuminate; veins somewhat visible, pinnate in pinnules, lateral veins 4-7 pairs, simple (basal acroscopic veins frequently forked). Lamina papery when dried, brown, glabrate on both surfaces; rachis and costae stramineous, with very short spines on adaxial surface in distal part of costa, often with rather dense pallid unicellular hairs abaxially, with hairs also at sinus between segments. Sori large, oblong, 5 or 6 pairs per pinnule, supramedial on veins, reaching pinna margin; indusia brown, oblong, thickly membranous, subentire, persistent, often hidden under sporangia at maturity. Perispore surface without folds. 2n = 80.

Bamboo and coniferous forests on gentle mountain slopes; 2300-3600 m. W Sichuan, Xizang, NW Yunnan [Bhutan, N India, Nepal].