狭叶蹄盖蕨 xia ye ti gai jue

Asplenium filix-femina (Linnaeus) Bernhardi var. flabellulata C. B. Clarke, Trans. Linn. Soc. London, Bot. 1: 493. 1880; Athyrium filix-femina (Linnaeus) Roth var. deltoidea Christ, p.p.; A. filix-femina var. flabellulata (C. B. Clarke) Beddome; A. tenuifolium Y. T. Hsieh & C. R. Wang (1983), not Copeland (1929).

Rhizomes short, erect, apex densely clothed with brown or chestnut-brown, ovate or ovate-lanceolate scales. Fronds caespitose; fertile fronds 37-40 cm; stipe blackish brown at base, upward stramineous, 10-13 cm, 1.5-2.5 mm in diam. at base, base similarly densely scaly, upward glabrate; lamina 2-pinnate, lanceolate, 27-32 × 7-9 cm at middle, base gradually narrowed, apex acuminate; pinnae ca. 18 pairs, lower pinnae opposite, upper pinnae alternate, ascending, lowest 4 pairs of pinnae gradually shortened; basal pinnae ovate-oblong, 2-2.5 × 1.4-2 cm; middle pinnae lanceolate, 4.5-6.5 × 1.5-2 cm at middle, base truncate and broadened, basal acroscopic base overlaying rachis, pinnate, apex acuminate; pinnules 8-11 pairs, basal pinnules subopposite, upper pinnules alternate; middle pinnules spreading, sessile, oblong or narrowly ovate, 8-10 × 4-5 mm at middle, base broadly cuneate, slightly inequilateral, somewhat auriculate on acroscopic side, cuneate on basiscopic side, pinnatifid to 1/3-1/2, apex obtuse or acute, toothed; pinnule segments oblong, toothed at margin; veins pinnate in pinnules, 5 pairs, lower veins forked, upper veins simple. Lamina herbaceous when dried, brown-green adaxially, yellow-green abaxially, glabrate on both surfaces; rachis and costae pale purplish red abaxially, with subulate short spines adaxially. Sori oblong, sometimes J-shaped, 1 per segment, uniseriate on each side of midrib, slightly closer to midrib; indusia brown, oblong, sometimes J-shaped, firmly membranous, subentire or ciliate, persistent. Perispore surface without folds, with granular ornamentation. 2n = 80.

Coniferous forests; (2800-)3700(-4000) m. SE Xizang [Bhutan, N India, Nepal].

Athyrium flabellulatum is morphologically intermediate between A. mehrae and A. davidii and has erect rhizomes and subulate short spines on the adaxial side of the rachis and costae.