泸定蹄盖蕨 lu ding ti gai jue

Rhizomes short, erect, apex densely clothed with dark brown, membranous, linear-lanceolate scales. Fronds caespitose; fertile fronds up to 68 cm; stipe pale stramineous, ca. 25 cm, ca. 4 mm in diam. at base, base similarly densely scaly, upward glabrate; lamina 2-pinnate, deltoid-ovate, ca. 43 × 23 cm at base, base slightly narrowed, apex acuminate; pinnules pinnatipartite; pinnae 16 pairs, basal 1 or 2 pairs of pinnae subopposite, upper pinnae alternate, ascending, very shortly stalked (stalk ca. 1 mm), oblong-lanceolate to lanceolate, 3 or 4 pairs of lower pinnae slightly narrowed at base, pinnules anadromous or subopposite; upper pinnae not narrowed or broadened at base, pinnules catadromous; middle pinnae 10-14 × 2-4 cm at middle, base subequilateral, truncate, somewhat auriculate on acroscopic side, cuneate on basiscopic side, pinnate, apex long acuminate to somewhat caudate; pinnules 15-20 pairs, lower pinnules opposite, upper pinnules alternate, oblong to deltoid-ovate; middle pinnules 1.2-1.7 cm × 3-5 mm, sessile, spreading or slightly ascending, base inequilateral, cuneate on basiscopic side, auriculate on acroscopic side, margin dentate or pinnatifid, apex acute; pinnule segments 5 or 6 pairs, oblong, apex dentate; veins visible abaxially, slightly visible adaxially, pinnate in pinnules, lateral veins 4 or 5 pairs, oblique, 1 or 2 veins forked per segment. Lamina herbaceous when dried, pale green; rachis and costae stramineous, with sparse brownish short hairs abaxially, margin of wing of costae, both surfaces of lamina, and margin of segments similarly shortly hairy, with subulate spines on adaxial side at base of costa or costule. Sori oblong, elliptic, shortly linear, or J-shaped, sometimes horseshoe-shaped, 1-2.5 mm, 4-6 pairs per pinnule, biseriate on both sides of costule, 1 per segment, inframedial on basal acroscopic veins, but often 2 or 3 in basal acroscopic pinnule segments; indusia brown, oblong, elliptic, or shortly linear, sometimes horseshoe-shaped, rarely J-shaped, membranous, erose at margin, persistent. Perispore surface without folds.

● Forests; ca. 2700 m. Sichuan (Luding).

Athyrium ludingense is very close to A. hirtirachis but differs by the adaxial surface of lamina and the margin of segments sparsely shortly hairy, the abaxial surface of costae and the margin of costa wings rather densely shortly hairy, and the pinnules narrowly triangular to deltoid-oblong and acute at apex.