网脉双盖蕨 wang mai shuang gai jue

Allantodia stenochlamys (C. Christensen) Ching ex W. M. Chu; Asplenium platyphyllum Baker (1890), not J. Smith (1859).

Plants evergreen, medium-sized. Rhizome erect, ca. 1.5 cm in diam., woody, apex and stipe base scaly; scales brown, toothed, lanceolate; fronds caespitose. Fertile fronds up to 1 m; stipe brown or light brown, 15-40 cm, 2-8 mm in diam., subfleshy, flattened when dry, upward without scales; lamina 1-pinnate or base 2-pinnate, deltoid or oblong, 20-60 × 15-30 cm, apex acuminate; pinnae 4-7 pairs, alternate, subspreading or ascending, basal 1 or 2 pairs of pinnae oblong, 9-23 × 3.5-7 cm, base subtruncate, with stalk 5-15 mm, pinnatilobate 2/3 to costa or only irregularly serrate, apex shortly acute; pinna lobes 4-6 pairs, subspreading, contiguous, narrowly ovate, base occasionally with acroscopic, stalked free pinnule, entire, rounded or acute at apex; veins prominent on both surfaces, pinnate, veinlets usually 7 or 8 pairs, basal 1 or 2 veinlets connected into excurrent veinlets, basal areoles deltoid (pentagonal) or tetragonal. Lamina thinly papery, brown-green when dry, glabrous on both surfaces, rachis green-brown or pale brown. Sori long linear, variably long, from near midrib to pinna margin, single or double; indusia yellow-brown, membranous, persistent. Spores bean-shaped, perispore prominent and hyaline, with granular ornamentation on surface.

Evergreen broad-leaved forests, beside streamlets; 100-900 m. SE Yunnan [N Vietnam].