Onychium contiguum C.Hope

Family

Pteridaceae, subfamily Pteridoideae

Nomenclature

Onychium contiguum C.Hope, J. Nat. Hist. Soc. Bombay 13: 444. 1901; Ching, Lingnan Sci. J. 13: 498. 1934; Tagawa & K.Iwats. SouthE. Asian Stud. 5: 108. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 196, f. 15.1. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 124. 2000.

Description

Rhizome creeping, bearing rather close-set stipes, densely covered with scales; scales narrow, brown to deep brown, thin but firm, entire, 3–6 mm long. Stipes stramineous except dark basal portion, black portion up to 5 cm long, grooved on adaxial surface, scaly at base, glabrous upwards, up to 20(–31.5) cm long. Laminae oblong-subdeltoid, quadripinnate, 13–20(–42) by 8–15 cm; rachis stramineous, grooved on upper surface, the grooves decurrent to those on pinna-rachis, glabrous; lateral pinnae largest at base, gradually becoming smaller upwards, basal acroscopic pinnule the largest; segments (4th division in larger pinnae) 2–5 lobed, spathulate; ultimate lobes lanceolate, acuminate at apex, entire, up to 2 by 0.5 mm, one-nerved; herbaceous to softly papyraceous, glabrous on both surfaces, green. Fertile segments 2–4 mm long, lower surface covered with sporangia, completely protected by reflexed marginal flaps.

Distribution in Thailand

NORTHERN: Chiang Mai, Chiang Rai.

Wider Distribution

N India, SW China and Taiwan.

Ecology

On dry sandy slopes below limestone cliffs or in crevices of limestones in light shade.

Proposed IUCN Conservation Assessment

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

Voucher specimens - Thailand

Maxwell 05-644, Chiang Rai (CMU).

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