狭基蹄盖蕨 xia ji ti gai jue

Athyrium stenopodum Ching & S. K. Wu; A. tibeticum Ching.

Rhizomes erect, apex densely clothed with brown, lanceolate to broadly lanceolate scales. Fronds caespitose; fertile fronds (20-)35-48(-80) cm; stipe blackish brown at base, upward brown-stramineous, (3-)8-20 cm, base (1-)1.4-2(-5) mm in diam., similarly densely scaly, upward glabrate; lamina pinnate-pinnatipartite, oblanceolate, (18-)26-38(-60) × (3.5-)5.5-7(-15) cm above middle, base gradually narrowed, apex acuminate; pinnae 25-30 pairs, alternate, subspreading, sessile, lower 6-9(-12) pairs of pinnae gradually shortened, basal pinnae often reduced to triangular auricles, 5-7(-20) mm, deflexed, middle pinnae lanceolate to broadly lanceolate, up to 3.5-6.5 × 1-1.4 cm, base broadened, equilateral, truncate or subcuneate, pinnatipartite to 1 mm to winged costa, apex shortly acuminate to caudate-acuminate; pinna segments 10-12(-17) pairs, basal segments opposite, upper segments alternate, slightly ascending or subspreading, approximate, oblong to lanceolate, basal segments larger, 4-6 × 1.8-3 mm, dentate at margin, apex obtuse-rounded and toothed; veins inconspicuous adaxially, visible abaxially, pinnate in segments, lateral veins 4 or 5 pairs, oblique, lower veins forked, upper veins simple, thin. Lamina herbaceous when dried, greenish brown, glabrate on both surfaces, with subulate spines at base of pinnae and pinna segments on adaxial side. Sori small, orbicular, 1 or 2(or 3) per segment, inframedial on basal acroscopic veins, close to midrib; indusia brown, small, orbicular-reniform, membranous, entire or erose at margin, persistent. Perispore surface without folds, with granular ornamentation. 2n = 80.

Forests, shrub meadows, on rocks of mountain slopes; 3100-4100 m. SE Xizang, Yunnan [India (Sikkim)].

J. Z. Wang and S. H. Li (in P. Y. Fu et al., Clav. Pl. Chin. Bor.-Orient. 35. 1995) considered that Athyrium rupestre Kodama occurs in Jilin. It is characterized by the perispore surface without folds and the pinnae pinnatipartite to pinnatisect, less than 1 cm wide, and long acuminate. Athyrium rupestre is distributed in Hokkaido and N Honshu, Japan, and E Russia. If the identification by J. Z. Wang and S. H. Li (1995) is correct, the species should be new to China.