褐柄双盖蕨 he bing shuang gai jue

Allantodia petelotii (Tardieu) Ching.

Plants evergreen, medium-sized. Rhizome erect, brown, ca. 1 cm in diam., apex like base of stipe, densely scaly, with dense, brown, stiff, fleshy, thick roots; scales brown, linear-lanceolate, 6-7 mm, membranous, entire; fronds caespitose. Fertile frond up to 1.2 m; stipe brown at base, upward green-brown, 35-40 cm, 6-7 mm in diam., base scaly, upward subglabrous, shallowly grooved adaxially; lamina 2-pinnatilobate to pinnatisect, or lower part of middle pinnae 1-pinnate, ovate-deltoid, up to 90 × 50 cm, apex acuminate; pinnae up to 12 pairs, slightly ascending, lanceolate, broadly oblong-lanceolate, or broadly deltoid-lanceolate, apex acuminate; basal 1 pair or 2 pairs of pinnae usually shorter; middle pinnae largest, up to 30 × 15 cm, lower 1-5 pairs of pinnules sessile or adnate; pinnules up to 15 pairs, oblong and acute, or lanceolate and long acuminate, up to 7 × 1.5 cm, base broadly cuneate, repand or obliquely crenate, slightly falcate; pinnule lobes mostly shallowly repand; veins visible on both surfaces, pinnate, veinlets 1-3 pairs, simple, ascending. Lamina herbaceous, brown-green when dry, glabrous on both surfaces; rachis green-brown, glabrous, shallowly grooved adaxially; costae abaxially occasionally with linear brown scales. Sori linear, 3-4 mm, up to 6 pairs, inframedial, from midrib to 1/2-2/3 of veinlet length, single or double on basal acroscopic veinlet; indusia brown, linear, membranous, entire, persistent.

Beside streamlets in dense forests; 100-400 m. Guizhou (Libo), SE Yunnan (Hekou, Jinping) [N Thailand, N Vietnam].