Description from Flora of China
Polypodium pedatum Houttuyn, Nat. Hist. 14: 175. 1783; Dicranopteris dichotoma (Thunberg) Bernhardi; D. linearis (N. L. Burman) Underwood; D. linearis var. alternans (Mettenius) Holttum; D. linearis var. subpectinata (Christ) Holttum; D. linearis var. tetraphylla (Rosenstock) Nakai; D. subpectinata (Christ) C. M. Kuo; D. tetraphylla (Rosenstock) C. M. Kuo; D. warburgii (Christ) Nakai; Gleichenia dichotoma (Thunberg) Hooker; G. dichotoma var. alternans Mettenius; G. linearis (N. L. Burman) C. B. Clarke; G. linearis var. tetraphylla Rosenstock; G. subpectinata Christ; G. warburgii Christ; Mertensia dichotoma (Thunberg) Willdenow; M. linearis (N. L. Burman) Fritsch (1901), not Greene (1897); P. dichotomum Thunberg (1784); P. lineare N. L. Burman.
Plants 0.5-2(-3) m tall. Rhizomes creeping, 2-3 mm in diam., covered with dense dark brown or brown hairs. Stipe stramineous, 0.3-1(-2) m, 2-6 mm wide, glabrous; rachis 1-3(-5) times dichotomously branched, basal internode 10-15 cm, covered with dark brown hairs, glabrescent, second internode 3-5 cm; apical buds ca. 2 mm, covered with dense brown hairs; bracts ovate to ovate-oblong, 5-10 mm, margin irregularly crenate, rarely entire; rachises with a pair of lateral stipulelike pinnae at each dichotomy; lower lateral pinnules broadly lanceolate, 10-25 × 4-7 cm, upper ones smaller, 4-10 × 2-4 cm; ultimate pinnae lanceolate or broadly lanceolate, 15-25(-35) × 4-8(-10) cm, base attenuate, apex caudate; lobes 15-50 on each side, linear-lanceolate or lanceolate, 10-50 × 2-4 mm, margin entire, apex emarginate or obtuse; lamina papery, glaucous abaxially, yellowish green or green adaxially, with sparse brown hairs on costae and veins abaxially; costae prominent on both surfaces; veins 3-5 in each group. Sori in 1 line on each side of costule; sporangia 5-8.
Dicranopteris pedata cannot be distinguished from D. linearis with any clear discriminative characters. The Japanese form is easily included in the range of variable forms of so-called D. linearis, and no infraspecific taxa are recognized under that variable species in the present treatment.
Dicranopteris linearis is widely distributed in tropical areas of S Asia and is sometimes an invasive weed. It is very variable, and Holttum (Fl. Males., Ser. 2, 1: 33-36. 1959) recognized thirteen varieties, four of which have been reported in Taiwan: D. linearis var. linearis, D. linearis var. montana (here treated under D. taiwanensis), D. linearis var. subpectinata, and D. linearis var. tetraphylla. These were separated by the presence or absence of hairs on the pinnules, rachis dichotomies equal or unequal, presence or absence of lateral pinnae subtending the ultimate pinnae, and dimensions of the pinnae (Fl. Taiwan, ed. 2, 1: 92-94. 1994); however, we believe that these vary too continuously to justify the recognition of distinct taxa.
The status of Gleichenia linearis var. longicauda Christ (Bull. Herb. Boissier 7: 19. 1899), described from Yunnan, is uncertain.
Thickets, forests, valleys, by rivers, hillsides; below 100-2200 m. Anhui, Fujian, Gansu (Wenxian), Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangsu, Jiangxi, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [India, Indonesia, Japan, Malaysia, Nepal, Singapore, Sri Lanka, Thailand, Vietnam; Australia].