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 latifolium Lam., Encycl. 1: 43. 1783; Proctor in Howard (ed.), Fl. Lesser Antilles 2: 114. 1977; Mickel & Smith, Pteridophytes of Mexico: 31. 2004; Boonkerd et al., Thai For. Bull. (Bot.) 32: 7. 2004.

Description

Terrestrial. Rhizome long creeping, 2–3 mm diam., fronds widely spaced; scales pale brown, 2–3 x 0.5–0.8 mm, linear-lanceolate, clathrate, margin entire or weakly toothed. Stipes dark brown to black, 26–53 cm long, 2–3 mm wide, glabrous to long brown pubescent or stipe and rachis; lamina bipinnate at base, simple pinnate at apex, 19.5–40 by 18–30 cm, more or less triangular to ovate in outline, 1–2(–4) pinnae on each side which are again pinnate plus a pinnate terminal portion similar to the lateral branches, pinnae 7.5–15 cm long, 3.7–6 cm wide; pinnules dimidiate, oblong to triangular, sometimes slightly falcate, more or less sessile, 1.5–6 by 0.5–1.6 cm, apex obtuse to rounded, base obtuse to cuneate, glabrous above and beneath, margin of sterile pinnules minutely sharply serrate, venation simple, repeatedly forked. Sori several along upper edge and approximately outer half of lower margin of each segment, 2–5 mm long, oblong .

Distribution in Thailand

PENINSULAR: Phangnga, Krabi, Satun, Songkhla, Yala, Narathiwat.

Wider Distribution

Neotropical, naturalised in the palaeotropics.

Ecology

Disturbed open areas.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is weedy and frequently naturalises outside of its natural range.

Voucher specimens - Thailand

Watthana & Pumicong 2081, Phangnga, Taphud (CMU); Maxwell 06-558, Krabi, Klong Tawm (CMU); Larsen et al. 45772, Songkhla, Ton Nga Chang National Park (QBG); Suksathan 2416, Yala, Khao Pok Yo (QBG); Niyomdham et al. 944, Narathiwat, Sungai Kolok (P).