4. Pteridium revolutum (Blume) Nakai, Bot. Mag. (Tokyo). 39: 109. 1925.
毛轴蕨 mao zhou jue
Plants up to 1 m tall. Rhizome long creeping. Fronds subleathery when dried, margins often revolute; stipe straw-colored or brown, 35-50 cm, 5-8 mm in diam. at base, adaxially grooved, densely clothed with pallid hairs when young, glabrous when old; lamina 3-pinnate-pinnatifid, broadly triangular or ovate-triangular in outline, 30-80 × 30-50 cm, apex acuminate; pinnae 4-6 pairs, opposite, decumbent, oblong, base subtruncate, stalked (2-3 cm), apex acuminate; basal pinnae 2-pinnate-pinnatifid, slightly triangular, 20-30 × 10-15 cm, stalked (2-3 cm); pinnules to 12-18 pairs per pinna, opposite or alternate, spreading, sessile, lanceolate, 6-8 × 1-1.5 cm, base truncate, not adnate to costule, deeply pinnate, apex shortly caudate-acuminate; ultimate pinnules ca. 20 pairs per pinna, opposite or alternate, slightly obliquely spreading, lanceolate-falcate, ca. 8 × 3 mm, base connate to costule, often entire, apex obtuse or acute; apical pinnae 2-pinnate-pinnatifid, lanceolate; segments approximate, with pallid or light brown hairs abaxially; veins prominent abaxially, grooved adaxially; rachises, costae, and costules approximate, with pallid or light brown hairs or verrucose, glabrescent.
Sunny slopes, open shaded forests; 600-3000 m. Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangxi, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [widely distributed in tropical and subtropical regions of Asia; N Australia].
