大型双盖蕨 da xing shuang gai jue

Gymnogramma gigantea Baker, J. Bot. 27: 177. 1899; Allantodia gigantea (Baker) Ching; A. sunghsienensis Ching & Y. P. Hsu; Diplazium falccidum Christ.

Plants summer-green, large. Rhizome creeping, apex densely scaly; scales brown, narrowly lanceolate or linear-lanceolate, membranous, margin sparsely toothed, often black (sometimes black margin discontinuous or not prominent), apex linear, caudate; fronds caespitose. Fertile frond more than 2 m; stipe dark brown at base, upward stramineous or green-stramineous, up to 90 cm, up to 1 cm in diam., base densely scaly, scales similar to those on rhizome, upward gradually glabrous, deeply grooved adaxially; lamina 2-pinnate with pinnatipartite pinnules, deltoid, up to 1.5 × 1 m, apex acuminate; pinnae ca. 15 pairs, alternate, slightly ascending, mostly broadly oblong-lanceolate; apex acuminate; basal 2 pairs of pinnae largest, up to 60 × 20 cm, with stalk 2-6 cm, pinnate; upper pinnae reduced to lanceolate, pinnatilobate, sessile or subsessile; pinnules up to 20 pairs, alternate or subopposite, spreading or subspreading, lanceolate or oblong-lanceolate, base asymmetrical (basiscopic side shallowly cordate, acroscopic side broadly cuneate or subtruncate, acroscopic lobes often smaller), shortly stalked or sessile, pinnatifid to pinnatipartite, apex acuminate or shortly acuminate; middle pinnules up to 15 × 5 cm; pinnule lobes up to ca. 15 pairs, slightly ascending, oblong, margin entire or crenate, apex rounded or subtruncate; veins visible abaxially, inconspicuous adaxially, pinnate, veinlets up to 9 pairs per pinnule lobe, ascending, often forked or simple, sometimes 3- or 4-furcate. Lamina herbaceous or thinly herbaceous when dry, pale green to gray-green abaxially, green adaxially, glabrous, veinlets with light brown or gray-white thin glands and pale brown small scales, midribs of pinnule lobes abaxially glandular; rachis and costae stramineous or green-stramineous, abaxially with pale brown short nodose hairs and many small scales, then glabrous. Sori mostly shortly linear, medial-inframedial, from base of midrib or near base to more than 2/3 of veinlet length, sometimes short, up to 7 pairs per pinnule lobe, often single or double on basal acroscopic veinlets (often forked along veinlets); indusia brown when mature, membranous, opening acroscopically, often part remaining, sometimes deciduous. Spores subreniform, perispore prominent, not rugate, granular ornamentation. 2n = 82.

Broad-leaved forests, beside streams; 400-2600 m. Chongqing, Guizhou, W Henan, W Hubei, S Jiangxi, Sichuan, Xizang, Yunnan [E Himalaya: Bhutan, NE India].