Etymology

According to Holttum (1954), the botanical name, Adiantum (unwetted) refers to the way in which water-drops run off the surface of the pinnae without wetting them.

Family

Pteridaceae, subfamily Vittarioideae

Nomenclature

Adiantum erylliae C.Chr. & Tardieu, Not. Syst. 6; 172, f. 1 & 2. 1938; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 184. 1940; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 110. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 213, f. 16.1. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 117. 2000. – Type: E. Smith 2322,Thailand, Tak, Raheng (P).

Description

Terrestrial or lithophytic. Rhizome short, erect, rather densely covered with scales; scales linear, 3–4 mm long, c.3 mm wide, indistinctly bicoloured with black centre somewhat paler brown margin, margin entire or with very occasional tooth. Stipes shiny, brown to nearly black, 2–20 cm long, glabrous except for scaly basal portion, scales like those on rhizome but concolorous dark brown. Laminae simply pinnate, 4–6 pairs of pinnae, lanceolate to linear-lanceolate, gradually narrowing upwards, 10–16 by 2.5–4 cm; rachis glabrous, often greatly prolonged and rooting at tip; lateral pinnae distinctly stalked, stalks 1.5–4 mm long; leaflets flabellate, 0.6–1.6(–2) by 0.6–2.7 cm, basal two edges entire, more or less straight to slightly curved outwards, base cuneate to obtuse, distal margin round, subentire or with shallow sinuses, middle sinus sometimes deeper to about half length of pinna, lamina thin, glabrous; veins repeatedly forking. Sori more or less semicircular to oblong, up to ten per pinna; false indusia 1–3 mm wide.

Distribution in Thailand

NORTHERN: Chiang Mai, Lampang, Tak; NORTH-EASTERN: Phetchabun, Khon Kaen; EASTERN: Chiayaphum; SOUTH-WESTERN: Kanchanaburi; PENINSULAR: Surat Thani, Phangnga, Krabi.

Distribution in Laos

Champasak.

Wider Distribution

Vietnam and Cambodia.

Ecology

On dry slopes or in crevices of limestone caves in light shade at low altitudes.

Similar species

Adiantum capillus-junonis Rupr.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is widespread but the limestone habitat on which it occurs is often exploited so its status should be reviewed.

Voucher specimens - Thailand

Middleton et al. 4517 & 4877, Chiang Mai, Doi Inthanon National Park (E); Nanakorn et al. 1684, Phetchabun, Nam Nao (QBG); Norsaengsri & Lakoet 3901, Khon Kaen, Phu Pha Man (QBG); Norsaengsri 3789, Chaiyaphum, Nong Bua Daeng (QBG).

Voucher specimens - Laos

Newman et al. 1991, Champasak (E); Thorel s.n., Champasak, Kong (P).