Adiantum phanomensis S.Linds. & D.J.Middleton


Named after the district of Thailand (Phanom) in which the type was collected.


Pteridaceae, subfamily Vittarioideae


Adiantum phanomensis S.Linds. & D.J.Middleton, Harvard Pap. Bot. 8: 137. 2004. – Type: Thailand, Surat Thani, Amphoe Phanom, Khlong Phanom National Park, c.100 m alt., 11 Aoril 2003, Middleton et al. 2133 (holo BKF; iso A, BKF).


Lithophytic on soft eroding limestone. Rhizome short, erect, covered with scales; scales narrow, black with a brown margin, 2–3 mm long, 0.1–0.2 mm wide. Stipe dark brown, 0.5–5.8 cm long, glabrous or with few scales near base. Laminae simply pinnate, 3–13 cm long, 1.4–4 cm wide, oblong in outline; rachis glabrous; pinnae 3–12 on each side of rachis, gradually becoming slightly smaller upwards; pinnae on stalks 2–8 mm long; pinnae flabellate, 6.5–20 by 5–11 mm, base narrow forming an angle of 40–80°, margins entire and straight, flat apex only weakly lobed with a narrow, inconspicuous sinus; thin, glabrous above, densely brown to grey pubescent beneath; veins dichotomous, slightly raised above (not visible beneath due to pubescence). Sori on flat apex of lobes, 2–4 reflexed soral flaps (false indusia), elongate , 2–4 mm long.

Distribution in Thailand

PENINSULAR: Surat Thani.

Wider Distribution

Endemic to Thailand. Known only from Klong Phanom and Khao Sok National Parks.


On steep banks of soft eroding limestone.

Similar species

Adiantum gomphophyllum Baker

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is geographically restricted but occurs in two well protected areas in Khao Sok and Khlong Phanom National Parks in Thailand.

Voucher specimens - Thailand

Middleton et al. 4322, Surat Thani, Khao Sok National Park (E); Middleton et al. 4359 & 5550, Surat Thani, Khlong Phanom National Park (E).







Rhizome and stipes

Rhizome and stipes

Site hosted by the Royal Botanic Garden Edinburgh. Content managed by Stuart Lindsay, Gardens by the Bay, Singapore and David Middleton, Singapore Botanic Gardens. Last updated 24 January 2012