边生双盖蕨 bian sheng shuang gai jue

Allantodia allantodioides (Ching) Ching; A. contermina (Christ) Ching; Diplazium allantodioides Ching; D. virescens Kunze var. conterminum (Christ) Sa. Kurata.

Plants medium-sized to large. Rhizome creeping or ascending, black, 1-1.5 cm in diam., up to 5 cm in diam. including remaining stipes, apex and base of stipe densely scaly; scales black or black-brown, slightly shiny, linear-lanceolate to linear, up to 1 cm or longer, thickly membranous, curly at apex, sparsely toothed at margin. Fronds distant to approximate or caespitose; stipe dark brown, green-stramineous, or stramineous at base, 20-100 cm, 2-6 mm in diam., lower part densely scaly, middle and upper part later glabrous; lamina 2-pinnate, deltoid, 30-120 × 25-100 cm, apex acuminate; pinnae 5-10 pairs, alternate, ascending, symmetrical, pinnatilobate, lanceolate, 5-10 × 1-3 cm, lower pinnae pinnate; basal pinnae largest, broadly lanceolate to oblong-lanceolate, up to 70 × 33 cm, apex pinnatilobate and acuminate; pinnules ca. 13 pairs, alternate, subspreading, slightly separated, nearly symmetrical, lanceolate to oblong, up to 16 × 4 cm, base subcuneate, broadly cuneate, or shallowly cordate, pinnatilobate to pinnatipartite, apex long acuminate or rounded; basal pinnules slightly shortened, lower pinnules with prominent stalk 3-4 mm; pinnule lobes up to ca. 15 pairs, ascending, oblong, margin shallowly serrate or subentire, apex rounded; veins not prominent on both surfaces or slightly visible abaxially, pinnate; veinlets up to 7 pairs per lobe, usually simple or occasionally forked, ascending. Lamina papery when dry, light green, glabrous adaxially, costules abaxially with sparse light brown linear scales; rachis and costa green-stramineous or stramineous, glabrous, shallowly grooved adaxially. Sori elliptic, up to 6 pairs per lobe, mostly single, supramedial or inframarginal; indusia gray-white, elliptic or cylindrical, membranous, oblique, vaulted, opening acroscopically, easily ruptured. Spores subreniform or bean-shaped, perispore not prominent, with short aculeate projections.

Dense valley forests, beside streamlets; 200-1000 m. Chongqing, Fujian, Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Taiwan, Yunnan, Zhejiang [Japan, Thailand, Vietnam].