玉龙耳蕨 yu long er jue

Sorolepidium glaciale (Christ) Christ; S. ovale Y. T. Hsieh.

Plants summer-green. Rhizome erect; scales dense, pale brown, ovate or broadly lanceolate, up to 5 mm, denticulate, acuminate. Fronds 4-9, 6-20 cm; stipe stramineous, 1-6(-8) cm, 1-2 mm in diam. at middle; basal stipe scales dense, reddish brown, ovate, broadly lanceolate, lanceolate, and linear, membranous, toothed, acuminate; distal stipe scales similar but smaller. Lamina 1-pinnate, yellowish green when dry, linear-lanceolate, 9-15 cm, 1.5-2.5 cm at middle, slightly contracted toward base, acute; rachis stramineous, without proliferous bulbils, densely scaly; scales similar to distal stipe scales, broadly lanceolate and linear, toothed, acuminate or caudate. Pinnae 14-28 pairs, alternate, attached at nearly right angles with rachis, sessile, deltoid-oblong, middle pairs 0.5-1.1 cm × 3-6 mm, bases nearly rounded and slightly asymmetrical, apices obtuse; acroscopic base auriculate, auricles semicircular, proximal margins of auricles slightly overlapping rachis, acroscopic margins subentire, basal basiscopic margins truncate, forming a 90°-130° angle with rachis, entire, distal basiscopic margins curved upward, entire; both surfaces densely scaly; microscales light brown, lanceolate, up to 2 mm; frond texture thinly leathery; venation pinnate on pinnae, lateral veins simple or forked, indistinct on both surfaces. Sori in 1 row on each side of midrib, 3-5 on each side of midrib, terminal on shorter veinlets, medial, whole lamina fertile, exindusiate. Spores elliptic in equatorial view; perispore sculpturing reticulate with echinate folds.

Frigid alpine mountains, calcareous rock crevices up to snow line or nearby glaciers; 3000-4700 m. Gansu, Qinghai, Sichuan, Taiwan, Xizang, Yunnan [Bhutan, NE India].