狭翅双盖蕨 xia chi shuang gai jue

Athyrium alatum Christ, Bull. Herb. Boissier 6: 963. 1898; Allantodia alata (Christ) Ching; Diplazium divaricatum Ching.

Plants evergreen, medium-sized to large. Rhizome creeping to ascending, apex like base of stipe, densely scaly; scales dark brown to black, linear-lanceolate, up to 2 cm or longer, entire, apex long caudate and curly; fronds caespitose. Fertile fronds up to 1.5 m; stipe black at base, upward dark stramineous or stramineous, sometimes green-stramineous, up to 75 cm, 3-5 mm in diam., glabrous; lamina 2-pinnate, deltoid, 40-80 × 40-80 cm, apex acuminate; pinnae 13-18 pairs, subspreading, nearly asymmetrical (basiscopic pinnule longer), apex often acuminate; basal to distal pinnae broadly lanceolate to broadly oblong-lanceolate to lanceolate, mostly alternate; basal pinnae often opposite or subopposite, ca. 40 × 20 cm, with stalk 1.5-6 cm; distal pinnae pinnatilobate, sessile or slightly shortly stalked, stalk winged; pinnules 10-15 pairs, mostly alternate, shortly stalked, spreading, lanceolate or oblong-lanceolate, pinnatipartite, slightly asymmetrical (basiscopic lobes longer), 5-15 × 1.5-4.5 cm, base truncate, apex acuminate or shortly caudate; basal lobes usually short; pinnule lobes 10-20 pairs, opposite or alternate, subspreading, oblong-lanceolate, slightly asymmetrical, base connected to narrow wings, 1-3 cm × 3-10 mm, pinnatipartite; secondary lobes of pinnule lobes up to 7 pairs, ascending, sickle-shaped oblong, apex entire or few crenate; veins not prominent, mostly pinnate or forked, few simple. Lamina thinly herbaceous, green when dry, glabrous adaxially, costa and base of pinnule lobes abaxially scaly; scales usually 1 or 2 (occasionally 3 or 4), red-brown, broadly ovate, thin; rachis and costa stramineous, shallowly grooved adaxially. Sori oblong or shortly linear, length 2/3-3/4 of veinlet, 1-4 pairs per each lobe, from base to above middle, single or double; indusia brown or gray-brown when mature, thinly membranous, often vaulted, ruptured. Spores subreniform, perispore surfaces with dense irregular aculeate projections.

● Wet broad-leaved forests and beside streamlets in deep valleys; 500-2200 m. S Guangxi, C Guizhou, Yunnan.