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 fragiliforme C.Chr., Bot. Tidsskr. 32: 347. 1916.

Description

Lithophytic. Rhizome short, erect, bearing a dense tuft of fronds, covered with scales; scales linear, slightly broader at base, entire, c. 8 mm long, brown, concolorous. Stipes terete, not grooved above, black, few scales at base, 3.5–19 cm long. Laminae tripinnate at base, 7–17 by 4.5–7 cm; rachis terete, glabrous, black; leaflets fan-shaped, distinctly stalked, 6–10 by 6–10 mm, base obtuse to acute, distal margin round, sometimes 2-lobed, thin, glabrous; veins not raised. Sori round, 1–2 mm long, 1–2(–4) to each leaflet.

Distribution in Thailand

SOUTH-EASTERN: Trat.

Wider Distribution

Cambodia

Ecology

In rock crevices above water in dry evergreen forest at low altitudes.

Similar species

Adiantum stenochlamys Baker

Proposed IUCN Conservation Assessment

Data Deficient (DD).  Due to confusion with other species the distribution of this species is not entirely clear.  It is posisble it only occurs in Trat and neighbouring areas in Cambodia so might have a very restricted distribution.

Notes

This species was combined with Adiantum stenochlamys Baker in the Flora of Thailand but without taking into account its distribution in South-East Thailand.  It differs in the generally smaller pinnae with fewer sori.

Voucher specimens - Thailand

Middleton et al. 4624 & 4626, Trat, Ko Chang, Trail from Khlong Phlu Ranger Station (E)