锡金双盖蕨 xi jin shuang gai jue

Asplenium sikkimense C. B. Clarke, Trans. Linn. Soc. London, Bot. 1: 500. 1880; Allantodia sikkimensis (C. B. Clarke) Ching; Diplazium brevicarpium Ching.

Plants evergreen, large. Rhizome erect, robust, up to 6 cm in diam., with fleshy thick roots; fronds caespitose. Fertile fronds up to 3 m or longer; stipe dark stramineous to light brown, up to 1.5 m, up to 1.4 cm in diam., with sparse brown, broadly ovate, adpressed, peltate scales; lamina 2-pinnate with pinnules pinnatipartite, deltoid, up to 1.5 m or longer, base up to 1.5 m wide, apex acuminate; pinnae up to ca. 10 pairs, alternate, ascending, with stalk up to ca. 10 cm, oblong-lanceolate, up to 75 × 23 cm, base truncate, apex acuminate; pinnules up to 17 pairs, subopposite, spreading, subsessile, lanceolate, up to 12 × 3 cm (to base), base truncate, margin pinnatipartite to 4/5 to costule, apex acuminate; basal pair of pinnule lobes slightly reduced; pinnule lobes up to 16 pairs, spreading, oblong, up to 1.4 cm × 6 mm, slightly oblique, margin slightly serrate, apex rounded; veins visible adaxially, prominent abaxially, pinnate, veinlets 5-8 pairs per lobe, bifurcate, ascending. Lamina papery, green abaxially, gray-green adaxially when dry, both surfaces glabrous; rachis dark stramineous, costa and costule stramineous or green-stramineous, prickly and scaly abaxially; scales brown, broadly ovate, cordate, adpressed. Sori very short, ovate or oblong, slightly longer than wide, up to 1 mm, up to 6 pairs per pinnule lobe, mostly single, some double; indusia brown, ovate, thickly membranous, vaulted, irregularly ruptured on back. Spores reniform, perispore prominent, subglabrous on surface. 2n = 82.

Rain forests, beside streamlets; 400-1100 m. Yunnan [India (Sikkim), Myanmar].