Lepisorus thunbergianus (Kaulfuss) Ching var. angustus (Ching) Sa. Kurata; Polypodium caudatoattenuatum (Takeda) C. Christensen; P. lineare N. L. Burman f. caudatoattenuatum Takeda.

Plants 12-25 cm tall. Rhizomes long and creeping, 1.5-2 mm in diam., densely scaly; scales brown with paler margins, lanceolate, 2-3.5 × 0.5-0.9 mm, margin slightly denticulate, apex often long and filiform, center opaque, marginal 1 or 2 rows of lumina elongate, transparent. Fronds closely spaced; stipe straw-colored, 1.5-3 cm, 0.8-1.2 mm in diam., base with 4 vascular bundles; lamina greenish or yellowish green to grayish green when dried, narrowly lanceolate, (10-)15-25 × 0.3-0.5 cm, widest at middle, leathery, abaxially sparsely scaly, scales small, lanceolate, transparent or with center opaque, base attenuate, long decurrent, margin straight or slightly sinuate, apex long acuminate; costa raised on both sides, veinlets obscure. Sori on distal half of lamina, slightly closer to costa, elliptic, orbicular, or shortly club-shaped, 1.5-2 mm in diam.; paraphyses deep brown, suborbicular, 0.2-0.35 mm in diam., central lumina dense, thick, opaque or transparent. Spore surface foveolate.

Lepisorus angustus is allied to the L. thunbergianus complex, differing only by the linear lamina. Material from Yichang transplanted into a greenhouse produced lanceolate new leaves, so the status of this species needs further study.

● On tree trunks or rocks in forests; (900-)2000-2800(-3500) m. Anhui, Chongqing, Gansu, Guangxi, Henan, Hubei, Hunan, Shaanxi, Sichuan, Xizang, Yunnan, S Zhejiang.