Family

Pteridaceae, subfamily Pteridoideae

Nomenclature

Pteris semipinnata L., Sp. Pl.: 1076. 1753; Bedd., Handb. Ferns Brit. India: 109, f. 58. 1883; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 151. 1940; Holttum, Rev. Fl. Malaya ed. 1, 2: 401, f. 232. 1955 [‘1954’]; Tagawa & K.Iwats., Fl. Thailand 3: 243. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 131. 2000.

Description

Rhizome short, ascending, covered with scales: scales narrow, bicoloured, the central portion dark brown, stiff, 3.5 by 0.2 mm, the marginal portion pale brown, ferrugineous, about a half the breadth of central portion. Stipes about 50 cm long, purplish or dark at basal portion, polished, glabrescent, narrowly grooved on upper surface. Laminae elliptic, up to 50 by 25 cm, bipinnatisect; lateral pinnae 4–7 pairs, bearing 3–6 basiscopic segments and long terminal ones, about 15 cm long, up to 6 cm wide, the acroscopic side entire, cuneate at base with short stalk; basiscopic lateral pinnules gradually becoming smaller distally, narrowing towards acute apex, dentate in sterile ones, up to 50 by 8 mm, apical segments up to 10 cm long; costa purple, polished, grooved on upper surface, papyraceous, deep green on upper surface, paler beneath; veins forked, all free, paler and visible on both surfaces. Sori linear, continuous along the margin nearly throughout the segments and acroscopic pinna-margin; indusia paler, stiff, nearly entire , up to 0.6 mm broad.

Distribution in Thailand

NORTHERN: Phitsanulok; EASTERN: Nakhon Ratchasima.

Distribution in Laos

Khammouane.

Wider Distribution

S China, Burma, Indochina, Malesia, north to southern edge of Japan.

Ecology

In evergreen forests at middle elevation.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is widespread and not under any known threat.