Plants up to 2 m tall. Rhizome creeping. Fronds papery when dried; stipe apically straw-colored, robust, ca. 0.8 m, up to 1 cm in diam., glabrous; lamina abaxially cinereous-green, adaxially green, 3-pinnate-pinnatifid, triangular in outline, ca. 1.2 m, abaxially with sparse pallid hairs or glabrescent, adaxially glabrous; pinnae ca. 5 pairs; basal pinnae opposite, obliquely spreading, 2-pinnate-pinnatifid, oblong-triangular, up to 90 × 40-50 cm, base broadly cuneate, stalked (up to 9 cm), apex acuminate; pinnules ca. 50 pairs, alternate, spreading, at nearly 90° angle to costa, narrowly linear; basal basiscopic pinnules ca. 20 × 3 cm, base truncate, sessile, apex acuminate; ultimate pinnules ca. 40 pairs per pinnule, spreading, linear-lanceolate, ± falcate, 1.5-2 cm, base nearly symmetrical, adnate to costules, not decurrent, separated by narrow sinuses, generally basal margins ± slightly lobed or undulate, entire upward, apex acute; basal pair close to costules and parallel to costules; basal acroscopic pinnules shorter, 1/3-1/2 as long as basiscopic pairs (0.5-1 cm); middle pinnules similar to basal pair, apical pairs shorter; veins forked twice from base, veinlets approximate, abaxially conspicuous, adaxially somewhat grooved; rachis, costae, and costules adaxially grooved, often with sparse pallid hairs in grooves, abaxially sparsely pubescent or glabrate.
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