薄盖双盖蕨 bao gai shuang gai jue

Allantodia hachijoensis (Nakai) Ching; A. omeiensis (Ching) Ching; Athyrium hachijoense (Nakai) Ohwi; Diplazium omeiense Ching; D. siroyamaense Tagawa.

Plants medium-sized to large. Rhizome creeping, black-brown, 5-10 mm in diam., apex densely scaly; scales brown to black-brown, lanceolate, 5-8 mm, thickly membranous, entire; fronds often approximate. Stipe of fertile frond black-brown at base, upward stramineous, dark stramineous, or pale brown, up to 70 cm, 2-5 mm in diam., base often with sparse scale remains, upward subglabrous, shallowly grooved adaxially; lamina 2-pinnate with pinnules pinnatipartite, deltoid or ovate-deltoid, up to 80 × 70 cm at base, apex acuminate; pinnae ca. 10 pairs, alternate, ascending, lower pinnae short and broadly lanceolate, pinnae below apex 1-pinnate with pinnules pinnatilobate, stalked; upper pinnae lanceolate, pinnatilobate, shortly stalked or sessile; basal pinnae largest, up to 50 × 20 cm at middle, with stalk up to 5 cm; pinnules ca. 10 pairs, alternate, spreading, sessile or lower pinnules very shortly stalked, often lanceolate, up to 12 × 3 cm, sometimes shorter, 1.5-3 × 0.5-1 cm, oblong-ovate, base broadly cuneate or subtruncate, sometimes shallowly cordate, slightly asymmetrical, pinnatilobate to pinnatifid, apex acuminate or rounded; pinnule lobes 10 pairs or more, subspreading, contiguous, oblong or obliquely rectangular, slightly oblique, entire or sparsely shallowly serrate, rounded or truncate; veins pinnate, prominent abaxially, visible adaxially, veinlets ca. 7 or 8 pairs per pinnule lobe, usually simple or forked, occasionally 3-furcate, ascending. Lamina thickly herbaceous when dry, green, darker adaxially or nearly concolored on both surfaces; rachis and costa green-stramineous or light brown-stramineous, shallowly grooved adaxially, with many thin glands in groove, abaxially with deciduous multicellular short glandular hairs and sparse lanceolate brown small scales; costules and veins abaxially with similar glands and scales. Sori shortly linear or oblong, 5 or 6 pairs per pinnule lobe, median, single or double; indusia light brown, membranous, entire, opening acroscopically when mature, persistent. Spores bean-shaped, perispore prominent, slightly hyaline, often rugate. n = 123.

Broad-leaved forests; 400-1700 m. Anhui, Chongqing, Fujian, Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Sichuan, Zhejiang [Japan, Korea].