疏羽凸轴蕨 shu yu tu zhou jue

Aspidium laxum Franchet & Savatier, Enum. Pl. Jap. 2: 237. 1876; Dryopteris laxa (Franchet & Savatier) C. Christensen; D. macarthyi (Baker) C. Christensen; Lastrea laxa (Franchet & Savatier) Copeland; Nephrodium laxum (Franchet & Savatier) Diels; N. macarthyi Baker; Thelypteris laxa (Franchet & Savatier) Ching.

Plants 30-60 cm tall. Rhizomes long, decumbent or ascending, with sparse grayish white short hairs and reddish brown lanceolate scales, similar indument on stipe bases. Fronds approximate; stipes 10-35 cm, stramineous, above bases subglabrous; laminae narrowly oblong, 15-35 × 10-18 cm, bases nearly tapering, pinnate-pinnatifid, apices acuminate and pinnatifid; pinnae 8-18 pairs, subopposite, linear-lanceolate, 5-9 × 1-2 cm, bases truncate, ± symmetrical, sessile, pinnatifid and reaching narrow wings on both sides of costae; segments oblong-lanceolate, middle ones 4-8 × 2-3 mm, entire or densely crenate-sinuate, or parted into small segments, obtuse-pointed or acute at apices. Veins visible, veinlets forked on segments on proximal pinnae, others simple, 5-7 pairs per segment, proximal pair arising above base of costules, not reaching margins. Laminae herbaceous, green when dry, abaxially with spreading hairs throughout, adaxially with acicular hairs along rachises, costae, and veins. Sori small, orbicular, 4-6 pairs per segment, attached on ends of veinlets or acroscopic vein on forked veinlets, close to margins; indusia small, orbicular-reniform, membranous, green, when dry grayish yellow, sparsely pubescent.

Forests on mountains, dense valley forests; near sea level to 800 m. Anhui, Chongqing, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, S Korea].