Family

Thelypteridaceae

Nomenclature

Cyclosorus larutensis (Bedd.) Ching, Bull. Fan Mem. Inst. Biol. 10: 245. 1941; Holttum, Rev. Fl. Malaya ed. 1, 2: 284, f. 165. 1955 [‘1954’]. – Nephrodium larutense Bedd., Suppl. Ferns Brit. Ind.: 73. 1892. – Mesochlaena larutensis (Bedd.) Alderw., Malayan Ferns: 232. 1908; Sphaerostephanos larutensis (Bedd.) C.Chr., Index Filic. Suppl. 3: 172. 1934; Holttum, Fl. Males., Ser. II, Pterid. 1: 489, f. 12d–e. 1982 [‘1981’]; Boonkerd & Pollawatn, Pterid. Thailand: 229. 2000. – Thelypteris larutensis (Bedd.) Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 53. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 417. 1988. – Lectotype (Holttum, Flora Malesiana 1981): Kunstler 2398, Perak, Larut (K).

Description

Rhizome short; scales narrow, hairy. Stipes hairy throughout, scaly near base, bearing reduced pinnae, 40–70 cm to first full-sized pinnae. Laminae oblong-lanceolate, 50–70 by 30–47 cm, 7–14 pairs of full-sized pinnae, with a distinct terminal pinna; middle lateral pinnae narrowly lanceolate, gradually narrowing towards long-acuminate apex, subtruncate to broadly cuneate at sessile base, longest pinnae 19–30 by 2.5–4 cm, lobed to 1/4 way towards costa; segments oblique, round to obtuse at apex, papyraceous, pubescent on both surfaces; rachis and costa hairy, hairs setose, multicellular; veins pinnate, veinlets 10–12 pairs, several basal pairs uniting to form a long excurrent vein, hairy, glandular on under surface. Sori medial, oblong, hardly confluent at maturity; indusia oblong, persistent, up to 1.7 by 0.7 mm, bearing round, red, sessile glands and setose hairs.

Distribution in Thailand

PENINSULAR: Yala.

Wider Distribution

Peninsular Malaysia and Borneo.

Ecology

In shade at low altitudes (but in Peninsular Malaysia to 1000 m so likely to be found higher in Thailand).

Proposed IUCN Conservation Assessment

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