日本安蕨 ri ben an jue

Asplenium niponicum Mettenius, Ann. Mus. Bot. Lugduno-Batavi 2: 240. 1865; A. niponicum var. longipes Franchet & Savatier; A. niponicum var. minus Franchet & Savatier; A. niponicum var. uropteron (Miquel) Franchet & Savatier; A. uropteron Miquel; Athyrium biondii Christ; A. fissum Christ; A. matsumurae Christ ex Matsumura; A. niponicum (Mettenius) Hance; A. niponicum var. pachyphlebium (C. Christensen) Kitagawa; A. pachyphlebium C. Christensen; A. sylvestrii Christ; A. uropteron (Miquel) C. Christensen; A. yunnanense Christ.

Plants summer-green. Rhizomes shortly creeping, ascending, densely clothed with brownish, narrowly lanceolate scales at apex and stipe bases. Fronds caespitose; fertile fronds (25-)30-75(-120) cm; stipe blackish brown at base, upward stramineous, 10-35(-50) cm, base (1.5-)2-3(-5) mm in diam., with sparse small scales; scales pale brown, lanceolate, entire; lamina 2- or 3-pinnate, ovate-oblong, (15-)23-30(-70) × (11-) 15-25(-50) cm at middle, broadly rounded at base, abruptly narrowed at apex; pinnae under abruptly narrowed apex 5-7(-14) pairs, alternate, ascending, with stalk (3-15 mm), slightly curved upward; basal pair slightly longer and larger, oblong-lanceolate, (5-)7-15(-25) × (2-)2.5-6(-12) cm at middle, broadly cuneate or rounded at base, apex abruptly narrowed, long acuminate, somewhat caudate; middle pinnae lanceolate, pinnate to 2-pinnate; pinnules (8-)12-15 pairs, alternate, ascending or spreading, shortly stalked or subsessile, usually broadly lanceolate or oblong-lanceolate, sometimes lanceolate, 1-4(-6) × 1-2 cm, inequilateral at base, acroscopic side subtruncate, auriculate, parallel to costae, basiscopic side cuneate, dentate or pinnatipartite almost cut to wings of costules, apex acuminate; segments 8-10 pairs, lanceolate, oblong, or linear-lanceolate, deeply serrate at margin, acute at apex. Veins visible abaxially, pinnate in segments, lateral veins 4 or 5 pairs, oblique, simple. Lamina herbaceous or thinly papery when dried, pale green or yellow-green, glabrate on both surfaces; rachis and costae on abaxial surface pale purplish red, with sparse brownish linear small scales. Sori oblong, hooked, J-shaped, or horseshoe-shaped, 4-12 pairs per ultimate segment; indusia similar to sori in shape, brown, membranous, somewhat erose at margin, persistent or partly caducous. Perispore surface with prominent low folds. 2n = 80.

Forests, streamsides, shaded wet mountain slopes, shrubby and grassy slopes; near sea level to 2600 m. Anhui, Chongqing, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [India, Japan, Korea, Myanmar, Nepal, Vietnam].

Athyrium niponicum f. cristato-flabellatum (Makino) Namegata & Kurata (Enum. Jap. Pterid. 279, 338. 1961; A. niponicum var. cristato-flabellatum Makino, J. Jap. Bot. 1: 6. 1916; A. niponicum monstr. cristato-flabellatum Nakaike; 鸡冠蹄盖蕨 ji guan ti gai jue) is a malformed plant, with the pinnae or segments narrowed to flattened cristate apices. It is cultivated in Shandong (Qingdao).