西疆岩蕨 xi jiang yan jue

Acrostichum alpinum Bolton, Fil. Brit. 76. 1790; A. hyperboreum Liljeblad; Polypodium arvonicum Withering; Woodsia himalaica Ching & S. K. Wu; W. hyperborea (Liljeblad) R. Brown; W. ilvensis (Linnaeus) R. Brown var. alpina (Bolton) Watt.

Plants 8-12 cm tall. Rhizomes compact, ascending, with cluster of persistent stipe bases of ± equal length; scales concolorous, brown, lanceolate, ca. 5 mm, membranous, fimbriate. Fronds clustered; stipe reddish brown, lustrous, 1-2 cm, ca. 1 mm in diam., articulate below middle, sparsely scaly, and scales later fallen; lamina 1-pinnate-pinnatifid, lanceolate, 5.5-9 × 1-1.7 cm, herbaceous or thinly herbaceous, both surfaces glabrous, base attenuate, apex acuminate; rachis with sparse long hairs and linear-lanceolate scales; pinnae 9-11 pairs, separate, oblique; lower pinnae shorter than above, ovate, 2-3 mm; middle pinnae largest, ovate or deltoid-ovate, 5-9 × 4-7 mm, pinnatifid, with 3 or 4 pairs of lobes, apex acute; pinna lobes hemielliptic, 2-3 mm, margin usually involute when dried. Veins pinnate, ending in hydathodes close to laminar margin, obvious adaxially. Sori orbicular; indusia saucer-shaped, with fimbriate long-ciliate margin. 2n = 156.

Rock crevices; ca. 4000 m. Xizang [Russia; Europe, North America].

H. C. Levinge’s collection is the only record of Woodsia alpina from NW Himalaya. It is closely comparable to N European forms. It has always been identified as W. subcordata, or other allied species, and cited by some authors in the flora of N and NE China and the vicinity.