倒鳞耳蕨 dao lin er jue

Polystichum aculeatum (Linnaeus) Roth ex Mertens var. retrosopaleaceum Kodama, Bot. Mag. (Tokyo) 29: 330. 1915; P. tsingkanshanense Ching ex K. H. Shing & J. F. Cheng.

Plants evergreen. Rhizome erect or ascending, short, densely covered with linear brown scales. Fronds 50-80 cm; stipe yellowish brown, 24-52 cm, 4-5 mm in diam. at base, densely covered with linear, lanceolate, grayish brown scales and larger scales; large scales dense, grayish brown, ovate and ovate-lanceolate, up to 24 × 12 mm, densely serrulate, acute or acuminate to caudate. Lamina bipinnate, elliptic or elliptic-lanceolate, 36-63 cm, gradually contracted or slightly contracted toward base, lower part sterile, apex acuminate, fertile; rachis without proliferous bulbils, abaxially densely covered with linear, lanceolate, light brown or grayish brown scales and larger scales; large scales dense, ovate-lanceolate and broadly lanceolate, up to 7.5 × 2.5 mm, with dense small teeth, acuminate to caudate, obviously pointing downward. Pinnae 20-24 pairs, alternate, ascendant, shortly stalked, lanceolate, bases asymmetrical, apices acuminate; middle pinnae 9-12 × 1.8-2.2 cm, 1-pinnate; costa shallowly winged at pinna tip, abaxially densely covered with linear light brown scales. Pinnules 18-22 pairs, alternate, shortly stalked, oblong or deltoid-ovate, 1-1.5 cm × 5-6 mm, bases cuneate and decurrent, acroscopic margins entire or repand, rarely lobed, not aristate, with rounded auricles, basiscopic margins spinulose, apices acute with acute tips; basal acroscopic pinnules largest, pinnatipartite; long-filiform microscales dense abaxially, sparse adaxially; frond texture papery or thinly papery; venation pinnate, lateral veins 5-7 pairs, dichotomous, distinct. Sori (1-)4-6 pairs per pinnule, in 1 row on each side of midrib, medial, terminal on veinlets; indusia present, subentire. 2n = 82.

Forests; 600-1600 m. Anhui (Haozhai, Jiuhua Shan), Hubei (Wudang Shan), Jiangxi (Jinggangshan, Lushan), Zhejiang (W Tianmu Shan) [Japan, Korea].

The most important character of Polystichum retrosopaleaceum is that its rachis scales are ovate-lanceolate and broadly lanceolate and pointing downward.