南岳蹄盖蕨 nan yue ti gai jue

Rhizomes short, erect, apex with sparse dark brown, lanceolate scales. Fronds caespitose; fertile fronds up to 50 cm; stipe dark brown, upward brownish stramineous, 17-20 cm, ca. 2.4 mm in diam., base similarly scaly, upward glabrate; lamina 2-pinnate-pinnatipartite, with pinnatipartite pinnules, oblong, 25-30 × ca. 15 cm, base ± rounded, apex acuminate; pinnae ca. 13 pairs, alternate, ascending, with stalk 4-5 mm, basal pinnae not shortened, broadly lanceolate, up to 10 × ca. 3.5 cm, shortly acuminate at apex, equilateral and rounded at base, pinnate; pinnules ca. 12 pairs, alternate, ascending; basal pinnules shortly stalked (stalk ca. 1 mm), oblong-lanceolate, up to 2 cm × 7-8 mm, base subequilateral, truncate, not auriculate on acroscopic side, cuneate on basiscopic side, pinnatipartite nearly to costule, apex obtuse; pinnule segments 5 or 6 pairs, approximate, oblong; basal acroscopic segments larger, ca. 1 cm × 5 mm, with 3-5 long teeth, obtuse at apex; veins inconspicuous adaxially, visible abaxially, pinnate in segments, lateral veins 3 or 4 pairs, oblique, lower veins forked, upper veins simple. Lamina thinly herbaceous when dried, dark green, glabrate on both surfaces; rachis and costae dark brown, glabrate abaxially, with needlelike spines on adaxial side at base of costa, costule, or midrib. Sori oblong or orbicular, 1 per segment (2-4 in basal acroscopic one), 5 or 6 pairs per pinnule, close to costule; indusia brown, oblong or orbicular, membranous, entire, persistent. Perispore surface without folds.

● Shrub groves; ca. 800 m. Hunan (Heng Shan).

Athyrium nanyueense is very similar to A. imbricatum in appearance but differs by the rachis and costae glabrate abaxially and the pinnules subequilateral at base, not auriculate on acroscopic side, obtuse-acute at apex.