Family

Aspleniaceae

Nomenclature

Asplenium siamense Tagawa & K.Iwats., Acta Phytotax. Geobot. 25: 17. 1971; Tagawa & K.Iwats., Fl. Thailand 3: 281. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 177. 2000.

Asplenium trichomanes var. ?: Holttum, Dansk Bot. Ark. 20: 29. 1961.

Description

Lithophytic. Rhizome short, ascending or suberect, bearing several living fronds and numerous stipes without pinnae, and appearing brush-like, densely scaly; scales gradually narrowing from base towards acuminate apex, about 2.5 by up to 0.4 mm, nearly black with brown edges which becoming fimbriate or soft hairy in age. Stipes very dark purple to nearly black, polished, glabrous but scaly at base, up to 4 cm long or in smaller fronds less than 1 cm. Laminae simply pinnate except for the decompound apical portion, 3–8 cm long, lower half of lamina pinnate, 6–10 mm wide, nearly parallel at edges; pinnae sessile, 2–5 mm apart, rounded at apex, a little ascending and nearly straight at basiscopic side, subtruncate at inner side, and shallowly lobed at acroscopic edge, 3–7 by 2–3 mm, fallen ones leaving minute scars on rachis; lobes rounded, with round sinus; veins hardly visible, a few times forked, not reaching the margin of lobes; rachis bearing branches at middle or above, sometimes the axes forked a few times, each branch with the appearance of pinnate frond; the apical pinnae adnate at base ending in indistinct apical pinnae. Sori one to three in each lobe, 1–1.5 mm long; indusia covered under sporangia at maturity.

Distribution in Thailand

NORTH-EASTERN: Loei.

Wider Distribution

Endemic to Thailand.

Ecology

Sandstone rock at about 1300 m alt.

Proposed IUCN Conservation Assessment

Data Deficient (DD). This is a poorly known species currently only known from Phu Kradueng in Loei province.  Although this is a protected area the size and distribution of the population are unknown.