Description from Flora of China
Asplenium macrocarpum (Blume) Hooker var. unipinnatum C. B. Clarke; Athyrium macrocarpum (Blume) Beddome var. unipinnatum (C. B. Clarke) Beddome; A. obtusifolium Rosenstock; A. tenuissimum Kodama; Nephrolepis tenuissima Hayata.
Plants evergreen. Rhizomes erect or shortly ascending, clothed with dark brown, lanceolate scales at apices and stipe bases. Fronds caespitose; fertile fronds (10-)30-38(-50) cm; stipe dark brown at base, upward stramineous, 8-14(-18) cm, 1-1.5 mm in diam. at base, clothed with blackish brown short glandular hairs and brown small scales; lamina pinnate, lanceolate, (7-)22-28(-32) × (2.5-)3-4.5(-7) cm, base slightly narrowed, apex acuminate; pinnae 16-18 pairs, alternate, subspreading, stalked (stalk ca. 1 mm), basal 1 or 2 pairs of pinnae slightly shortened, inclined or recurved; middle pinnae oblong, (1-)2-2.5(-3.5) cm × (5-)6-7(-12) mm, base extremely inequilateral, prominently auriculate on acroscopic side, shortly toothed, obtuse at apex, auricles lingulate-oblong or subtriangular, 4-7 mm, cuneate on basiscopic side of pinna, margin deltoid-lobed or repand-toothed, entire or somewhat repand to dentate, apex obtuse. Veins inconspicuous adaxially, visible abaxially, pinnate in pinnae, lateral veins 8-10 pairs, usually forked, but pinnate in auriculate lobes. Lamina papery when dried, yellowish brown or greenish brown, glabrate on both surfaces; rachis stramineous, with sparse blackish brown or dark brown short glandular hairs. Sori large, mostly horseshoe-shaped or orbicular-reniform, sometimes J-shaped at pinna apex, supramedial on acroscopic veins, biseriate along both sides of costa, frequently 2-5 in auriculate lobes; indusia brown, large, horseshoe-shaped or orbicular-reniform, sometimes J-shaped, membranous, erose at margin, persistent. Perispore with few folds, slightly spinulose on surface. 2n = 160.
Evergreen broad-leaved forests, shrub groves, on rocks, streamsides in valleys; 1300-3400 m. Taiwan, SE Xizang, Yunnan [Bhutan, N India, Japan, Nepal].