轴生蹄盖蕨 zhou sheng ti gai jue

Asplenium rhachidosorum Handel-Mazzetti, Symb. Sin. 6: 33. 1929; Athyrium amoenum C. Christensen; A. densisorum X. C. Zhang; A. wuliangshanense Ching.

Rhizomes short, erect, apex densely clothed with dark brown, lanceolate scales. Fronds caespitose; fertile fronds (25-) 40-80 cm; stipe blackish brown, upward stramineous, (10-)15-30 cm, 1.5-2.5 mm in diam., base sparsely scaly, upward glabrate; lamina 2-pinnate to 3-pinnate-pinnatifid, oblong-lanceolate or oblong, (12-)20-45 × (6-)9-18 cm at middle, base almost not narrowed, apex acuminate; pinnae (8-)15-24 pairs, basal pinnae subopposite, upper pinnae alternate, oblique, with stalk (2-)4-7 mm, basal pinnae slightly shortened, second basal pinnae lanceolate or somewhat falcate, (3-)7-14 × 1.5-3.8 cm, base rounded-cuneate, 2-pinnate-pinnatifid, apex acuminate; pinnules (6-)10-20 pairs, alternate, anadromous, oblique, separate from each other, stalked, lanceolate, 1.2-2.5 cm × 5-9 mm, base inequilateral, rounded-cuneate, pinnate, apex acuminate; secondary pinnules 3-8 pairs, alternate, oblique, broadly linear or oblong, 3-6 × 1-2 mm, ± connate to each other by narrow wing of costule, pinnatipartite, apex obtuse, cuneate; ultimate segments 2-4 pairs, oblique, linear; veins visible on both surfaces, pinnate in ultimate pinnules, lateral veins 1-4 pairs, oblique, simple or forked in basal acroscopic veins. Lamina thinly herbaceous when dried, greenish brown, glabrate; rachis and costae stramineous abaxially, with needlelike spines on adaxial side at base of costa and costule. Sori small, elliptic, orbicular-reniform, or horseshoe-shaped, 1 per segment or ultimate pinnules, costular; indusia brownish, elliptic, orbicular-reniform, or horseshoe-shaped, membranous, subentire or erose, partly fugacious at maturity. Perispore surface without folds.

Mixed alpine forests; 1900-3700 m. SW Sichuan, Xizang, Yunnan [N Myanmar].