广南蹄盖蕨 guang nan ti gai jue

Athyrium acrocarpum W. M. Chu (1992), not (Rosenstock) Copeland (1951); A. guangnanense var. acrocarpum W. M. Chu; A. yunnanicum Ching.

Rhizomes short, erect, apex with sparse blackish brown, lanceolate scales. Fronds caespitose; fertile fronds 35-55 cm; stipe blackish brown, upward stramineous, ca. 22 cm, ca. 1.5 mm in diam. at base, base similarly scaly, with sparse scales, upward glabrate; lamina 2-pinnate, narrowly oblong, up to 30 × ca. 16 cm at middle, base slightly narrowed, apex acuminate; pinnae 15-17 pairs, opposite, subspreading, with short stalk 1-2 mm; basal pinnae slightly shortened, ca. 7 cm; middle pinnae lanceolate, 8.5-9 × 2.2-2.5 cm at base, base subequilateral, rounded-truncate, pinnate, apex caudate-acuminate; pinnules 16-18 pairs, lower pinnules opposite; upper pinnules alternate, ascending, approximate; basal pinnules slightly larger, oblong, 1.1-1.3 cm × ca. 5 mm at base, base subequilateral, truncate, parallel to costae on acroscopic side, cuneate on basiscopic side, subsessile, pinnatifid, apex obtuse-rounded, with 2 or 3 triangular teeth; veins visible on both surfaces, pinnate in pinnules, lateral veins ca. 5 pairs, oblique, forked, often pinnate in basal acroscopic segments. Lamina papery when dried, yellow-green, glabrate on both surfaces; rachis stramineous, costae pale purplish red, with sparse short hairs abaxially, with pale brown needlelike spines on adaxial side at base of costa, costule, or midrib. Sori oblong, lateral on basal acroscopic veins, 1 per segment, close to costule; indusia brown, oblong, membranous, entire, persistent. Perispore surface without folds.

● Forests; (600-)1100-1800(-2300) m. Guizhou, SE Yunnan.

Athyrium guangnanense is very close to A. viviparum but differs by the absence of bulbils on the rachis. The relationship between them requires further investigation.