Family

Athyriaceae

Nomenclature

Diplazium riparium Holttum, Gard. Bull. Straits Settlem. 11: 97, f. 5. 1940; Tagawa & K.Iwats., Fl. Thailand 3: 454. 1988; Boonkerd & Pollawatn, Pterid. Thailand: 195. 2000. – Athyrium riparium (Holttum) Holttum, Rev. Fl. Malaya ed. 1, 2: 554, f. 326. 1955 [‘1954’].

Description

Rhizome short, ascending to suberect; scales narrowing towards long-tailed apex, up to 15 by 1.3 mm, dark brown to nearly black, margined with caducous brownish membrane, entire. Stipes stramineous, scaly at base, 40–70 cm long. Laminae imparipinnate with less than four pairs of lateral pinnae, about 35 cm long and wide; rachis grooved on upper surface, minutely hairy, without buds; lateral pinnae oblong, subentire or serrate at margin, broadest at middle or upper portion, rounded at apex, gradually narrowing towards narrowly cuneate, sessile or adnate base, 12–25 by up to 5.5 cm; chartaceous, deep green above, paler below, glabrous; costa grooved above, raised below; veins widely placed on costa with angles of more than 60°, 2–3 times branched, free, visible on both surfaces. Sori along veins, from basal veinlets to minor branches, often on every veinlet, about 2 cm long; indusia thin but firm , pale brown when dried, attached by posterior side.

Distribution in Thailand

PENINSULAR: Surat Thani, Satun, Yala.

Wider Distribution

Peninsular Malaysia, Borneo, and Philippines.

Ecology

On muddy rocks or on earth by streams in dense forests at low altitudes.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is widespread and not under any known threat.