Description from Flora of China
Polypodium decursive-pinnatum H. C. Hall, Nieuwe Verh. Eerste Kl. Kon. Ned. Inst. Wetensch. Amsterdam 5: 204. 1836; Aspidium decursive-pinnatum (H. C. Hall) Kunze; Dryopteris decursive-pinnata (H. C. Hall) Kuntze; Lastrea decurrens J. Smith; L. decursive-pinnata (H. C. Hall) J. Smith; Leptogramma decursive-pinnata (H. C. Hall) J. Smith; Nephrodium decursive-pinnatum (H. C. Hall) Baker; Thelypteris decursive-pinnata (H. C. Hall) Ching.
Plants 30-60 cm tall. Rhizome short and erect, including base of stipe with reddish brown, ciliate, narrowly lanceolate scales. Fronds clustered; stipe stramineous, 10-25 cm; lamina lanceolate, 20-50 × 5-12 cm, gradually tapering to base, bipinnatifid or pinnate and toothed along margins, acuminate and pinnatifid at apex; pinnae 20-30 pairs, alternate, obliquely spreading, middle ones largest, narrowly lanceolate, 2.5-6 × ca. 1 cm, broad and decurrent at bases, connected by orbicular auricles or triangular wings between pinnae, pinnatifid to 1/3-1/2 of distance to costules, acuminate at apices; segments obliquely spreading, ovate-triangular, entire, obtuse at apices; pinnae gradually shortened to both ends, basal one pair of pinnae often shortened into small auricles. Veins pinnate, lateral veins simple and reaching margins. Fronds herbaceous, along rachis, costae, and veins with whitish unicellular acicular short hairs on both sides, abaxial side with forked and stellate hairs, abaxial side of rachises and costae with sparse brownish, hairlike or lanceolate, ciliate scales. Sori suborbicular, borne at or near ends of ultimate veins, 2 or 3 per segment, sometimes with tufts of stalked forked hairs in center when young. Sporangia each sometimes with 1 or 2 short hairs near annulus. 2n = 60, 90, 120.
Phegopteris decursive-pinnata is very different from other species of the genus in having short, erect rhizomes and narrowly lanceolate laminae, but it can spread by long-creeping rhizomes. Because of these characters, Iwatsuki removed it from Thelypteris sect. Phegopteris and treated it and some species that we place in Pseudophegopteris, as well as other species, in T. sect. Lastrea (Bory) Alston. Three ploidal levels are known, but these numbers do not clearly correlate with differing morphologies.
Along rivers on fluvial plains, lower montane regions of hills, forests by roadsides; sea level to 2000 m. Anhui, Chongqing, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, S Shaanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, S Korea, N Vietnam].