Family

Cyatheaceae

Nomenclature

Cyathea borneensis Copel., Philipp. J. Sci. 6: 135. 1911; Holttum, Fl. Males., Ser. II, Pterid. 1: 110. 1963; Holttum, Dansk Bot. Ark. 23: 229. 1965; Holttum, Kew Bull. 19: 469. 1965; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 45. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 102. 1979; Boonkerd & Pollawatn, Pterid. Thailand: 113. 2000.

Cyathea obtusata Rosenst., Meded. Rijksherb. 31: 1. 1917; Holttum, Rev. Fl. Malaya ed. 1, 2: 121. 1955 [‘1954’].

Description

Trunks to 2 m or more tall. Stipes about 10 cm long, with short spines throughout, scaly at base, dark purplish or brownish; scales linear, up to 2 cm long, 1 mm broad, dark brown, shining, edges ferrugineous, narrow, soon abraded; pneumathodes 1 cm or more in length, in a single row with a short distance between each other; main rachis with short spines at base only, smooth or warty, pale brown; lower pinnae distant, more than 10 cm apart, reduced to 5 cm long or so, variable in form; longest pinnae about 50 cm long, 18 cm wide, caudately acuminate at apex; pinna-rachis brown or paler, purplish at basal portion, sparsely hairy with pale crisped hairs and bearing very sparse pale brown scales; pinnules more than 25 pairs, larger ones 2.5 cm apart, very shortly stalked, patent, straight or more or less falcate, lanceolate, gradually narrowing towards acuminate apex, truncate at base, about 10 cm long, 2 cm wide, lobed almost to costae, remaining decurrent lamina 0.2–1 mm broad; lobes oblique, falcate, round at apex, serrate at margin, about 1 cm long, 4 mm broad; costae sparsely scaly beneath with entire, acuminate, dark, usually flat scales; thinly papyraceous, veins forked, distinct on both surfaces. Sori close to costules; receptacles swollen; indusia thin, flat, on costular side of receptacles, usually under mature sori , but visible.

Distribution in Thailand

EASTERN: Buri Ram; SOUTH-WESTERN: Phetchaburi; CENTRAL: Nakhon Nayok; PENINSULAR: Chumphon, Surat Thani, Nakon Si Thammarat, Satun, Trang.

Wider Distribution

Burma, Peninsular Malaysia and Borneo.

Ecology

On rather dry ground near rivers in light shade in tropical evergreen forest at 400–1800 m alt. or in lower montane forest at high altitudes, 1000–1600 m alt.

Proposed IUCN Conservation Assessment

Least Concern (LC). Although Cyathea species are often exploited for the horticultural industry (mainly for their trunks as a base for epiphytic orchids) this species is widespread and not noticeably being adversely impacted.  Monitoring is necessary.

Notes

Fibrous trunk used for orchid media.  It is reported for Cambodia in the Flora of Thailand but we have seen no specimens to support this.