Diplazium siamense C.Chr.




Diplazium siamense C.Chr., Contr. U.S. Natl. Herb. 26: 332, pl. 26. 1931; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 104. 1967; Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 116. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 460. 1988; Boonkerd & Pollawatn, Pterid. Thailand: 195. 2000.

Diplazium latilobum Holttum, Dansk Bot. Ark. 23: 308. 1966.


Rhizome erect; scales concolorous, brown, about 15 by 0.8 mm, irregularly minutely toothed. Stipes about 50 cm long, stramineous with dark scaly basal portion. Laminae oblong with acute apex, up to 70 by 30 cm, pinnate; lateral pinnae about 7 pairs below indistinct terminal portion of frond, with distinct stalks more than 1 cm long, gradually narrowing towards long acuminate apex, rounded to cuneate at base, up to 20 cm long, 3.5 cm wide in middle, lobed half-way to costa; terminal portion of frond lobed near base, gradually narrowing towards attenuate apex, up to 20 cm long; rachis and costa often minutely scaly, veins pinnate with 6–9 pairs of simple veinlets, the basal anterior ones ending below the sinus between lobes; lobes oblong, oblique, rounded to obtuse at apex, serrate; thinly chartaceous, green to deep green, paler below. Sori along veinlets, those on basal anterior veinlets not exceptionally elongate, rarely diplazioid; indusia thin but firm, persistent .

Distribution in Thailand

NORTHERN: Chiang Mai, Chiang Rai, Phrae, Phitsanulok; NORTH-EASTERN: Phetchabun, Loei.

Wider Distribution

Endemic to northern Thailand.


On humus-rich mountain slopes in mixed or evergreen forests at 850–1500 m alt.

Proposed IUCN Conservation Assessment

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

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