Arachniodes spectabilis (Ching) Ching

Family

Dryopteridaceae

Nomenclature

Arachniodes spectabilis (Ching) Ching, Acta Bot. Sin. 10: 259. 1962; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 93. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 343, f. 30.3–4. 1988; Boonkerd & Pollawatn, Pterid. Thailand: 200. 2000. – Rumohra spectabilis Ching, Sinensia 5: 58, pl. 11. 1934.

Description

Terrestrial. Rhizome short, erect; scales dense, narrow, up to 12 by 1.3 mm, brown, entire. Stipes stramineous, up to 60 cm long, scaly on basal part, glabrescent upwards; scales up to 20 by 1.5 mm, dark-brown, entire. Laminae oblong-subtriangular, gradually narrowing towards acuminate apex, tripinnate, up to 50 by 35 cm; rachis glabrous, grooved on upper surface; lateral pinnae more than 10 pairs, the lowest the largest, with large basal acroscopic pinnules, middle pinnae distinctly stalked, slightly falcate, linear-subtriangular, widest at base, gradually narrowing towards caudate-acute apex, about 20 by 5–6 cm, upper ones gradually becoming smaller; pinnules oblong-subdeltoid, acute at apex, unequally cuneate at stalked base, often dimidiate at posterior base; segments sessile, oblong, oblique, round to moderately acute, lobed at margin, up to 10 by 5 mm; lobes serrate at margin, ending with moderate awns; harsh, glabrous green on upper surface. Sori dorsal on veinlets, near midrib; indusia round, entirely covered and enveloping the sori when young, breaking down irregularly, about 1.5 mm diam.

Distribution in Thailand

NORTHERN: Mae Hong Son, Chiang Mai, Chiang Rai, Lampang, Phitsanulok; SOUTH-WESTERN: Kanchanaburi; SOUTH-EASTERN: Chanthaburi.

Wider Distribution

E Himalayas and SW China.

Ecology

On rather dry or humus-rich mountain slopes in mixed or in evergreen forests at 300–1500 m alt.

Proposed IUCN Conservation Assessment

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

Voucher specimens - Thailand

Middleton et al. 5049, Chiang Mai, Doi Pha Hom Pok National Park (E).

Whole frond

Whole frond

Rhizome

Rhizome

Transverse section through rhizome

Transverse section through rhizome

Stipe

Stipe

Lamina

Lamina

Frond apex

Frond apex

Costa/rachis junction showing confluence of grooves

Costa/rachis junction showing confluence of grooves

Upper surface of lamnia

Upper surface of lamnia

Lower surface of lamina and sori

Lower surface of lamina and sori

Sori

Sori

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