Family

Aspleniaceae

Nomenclature

Asplenium tenuifolium D.Don, Prod. Fl Nepal.: 8. 1825; Bedd., Handb. Ferns Brit. India: 159, f. 78. 1883; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 238. 1940; Tagawa & K.Iwats., Acta Phytotax. Geobot. 24: 62. 1969; Tagawa & K.Iwats., Fl. Thailand 3: 274. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 178. 2000. – Type: Wallich 216, Nepal (lectotype Brussels (designated by Morton); isolectotype US).  

Description

Terrestrial or lithophytic. Rhizome short, ascending to suberect, densely scaly; scales narrowly lanceolate, gradually narrowing from base towards apex, dark brown, clathrate, entire, about 4 by 0.8 mm. Stipes green above, dark brown or purplish and shiny below, grooved above, scaly at base, glabrescent above, about 6–12 cm long. Laminae oblong-subdeltoid, rounded at base, acuminate at apex, up to 22 by 10 cm, quadripinnate to quadripinnatifid; rachis sometimes gemmiferous; 10–19 pairs of pinnate pinnae, anadromic throughout, shortly stalked, unequally subtriangular, acuminate at apex, 2–8.5 x 1.2–5 cm, gradually becoming smaller upwards, basal ones a little smaller; pinnules ovate-subdeltoid, rounded to broadly cuneate at base, moderately acute to rounded at apex, up to 1.5 by 1 cm; secondary pinnules with a few lobed segments or a segment with a few lobes; ultimate lobes oblong, acuminate at apex, entire, about 1 mm broad, one-nerved; papyraceous, glabrous, light green. Sori one to each lobe, medial; indusia firm , pale green to whitish.

Distribution in Thailand

NORTHERN: Chiang Mai; PENINSULAR: Chumphon.

Wider Distribution

Sri Lanka, S India, E Himalaya from Nepal to India (Assam), SW China, Indochina and Taiwan.

Ecology

Lower montane forests along streams in moist places, on rocks or stream banks.

Proposed IUCN Conservation Assessment

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

Voucher specimens - Thailand

Middleton et al. 4890, Chiang Mai, Doi Inthanon National Park (E); Middleton et al. 5047, Chiang Mai, Doi Pha Hom Pok National Park (E).