大卫假冷蕨 da wei jia leng jue

Polypodium davidii Franchet, Nouv. Arch. Mus. Hist. Nat., sér. 2, 10: 119. 1887; Asplenium duthiei Beddome; Athyrium duthiei (Beddome) Beddome; Phegopteris davidii (Franchet) Beddome; Pseudocystopteris davidii (Franchet) Z. R. Wang.

Rhizomes long creeping, with remaining stipe bases, chestnut-black, glabrate, slightly shiny, 1-2 mm in diam., with sparse red-brown, ovate-lanceolate scales at apices and stipe bases. Fronds approximate or distant; fertile fronds 20-35 cm; stipe dark brown at base, upward stramineous, slightly pale purplish red, 2.5-12 cm, 1-2 mm in diam., upper part with few scales; lamina 2-pinnatifid, oblanceolate or narrowly oblanceolate, broadest 1/3 from apex, 14-25 × 3.5-8 cm, gradually narrowed toward base usually 1-2(-3) cm wide, acuminate; pinnae 13-24 pairs, sessile or subsessile, spreading or slightly ascending, subopposite; basal pinnae acroscopically subauriculate, usually 0.3-1.3 cm; longest pinnae slightly ascending, alternate, costae 0.5-3 cm from neighboring pinnae, lanceolate or broadly lanceolate, 1.5-4 cm × 5-14 mm, base subtruncate, subequilateral, or acroscopic segments slightly large, deeply pinnatifid to narrow wings, apex shortly acuminate; pinna segments or pinnules 10 pairs or fewer, ovate to ovate-triangular, 2-8 × 2-5 mm, slightly inequilateral at base, margin with sharp teeth or shallowly lobed, apex obtuse; ultimate segments with 2 or 3 short teeth. Veins visible abaxially, purplish red, lateral veins simple or 2- or 3-forked, ending into tooth tips. Lamina herbaceous or near papery when dried, dark greenish brown adaxially, pale green abaxially. Rachis and costae with few long scalelike hairs abaxially, costae and veins with sparse long multicellular hairs, costae also with short glandular hairs abaxially. Sori elliptic or reniform, 1-7 sori per segment, medial or supramedial; indusia small, thinly membranous, orbicular-reniform or narrowly ovate, lacerate at margin, hidden by sporangia at maturity. Spores bilateral, perispore folded. 2n = 80.

Cool alpine areas on mountains, grassy slopes, under shrub groves, in rock crevices; 3000-4300 m. W Sichuan, SE Xizang, NW Yunnan [N India, N Myanmar, Nepal].