Polystichum tenggerense Rosenst.

Family

Dryopteridaceae

Nomenclature

Polystichum tenggerense Rosenst., Repert. Spec. Nov. Regni Veg. 8: 164. 1910; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 95. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 338, f. 29.8 & 29.9. 1988; Boonkerd & Pollawatn, Pterid. Thailand: 209. 2000.

Description

Rhizome massive, erect; scales oblong-ovate, up to 2.5 by 1.2 cm, bicoloured, central portion dark castaneous to nearly black, thin but stiff, margins brown, ferrugineous. Stipes to 60 cm long, brown, grooved above, densely scaly throughout, scales of two kinds, larger ones oblong-ovate, narrow ones up to 1.2 mm in breadth, ferrugineous. Laminae tripinnate to tripinnatifid, oblong-lanceolate, hardly narrowing at base, gradually narrowing towards acute apex, 65–75 by 25–36 cm; rachis densely scaly, larger scales concolorously brown, up to 10 by 5 mm, linear ones ferrugineous, in upper part like downy hairs; pinnae up to 30 or more pairs, the lowest ones subopposite, a little deflexed, middle ones patent, slightly falcate, linear-lanceolate, subtruncate and sessile, attenuate at apex, up to 18.5 by 4.5 cm; pinnules patent, up to 30 pairs, oblong, moderately acute at apex, slightly auricled at acroscopic and dimidiate at basiscopic bases, up to 12 by 5 mm, lobed to half-way; lobes subdeltoid, acuminate at apex, about 1 mm long, up to 1.5 mm broad, apex ending in awns; veins pinnate, softly coriaceous, light green. Sori arranged in one row close to midrib of pinnules or medial between midrib and margin, confluent at maturity; indusia peltate, pale to deep brown, thin, fugacious, glabrous .

Distribution in Thailand

NORTHERN: Chiang Mai.

Wider Distribution

Sumatra and Java.

Ecology

In Thailand known only on Doi Inthanon, on humus-rich mountain slopes in dense mossy forest at about 2200 m alt.

Proposed IUCN Conservation Assessment

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

Voucher specimens - Thailand

Middleton et al. 4907, Chiang Mai, Doi Inthanon National Park (E).

Frond

Frond

Rhizome

Rhizome

Stipes

Stipes

Scales on stipe

Scales on stipe

Lower surface of lamina with sori

Lower surface of lamina with sori

Site hosted by the Royal Botanic Garden Edinburgh. Content managed by Stuart Lindsay, Gardens by the Bay, Singapore and David Middleton, Singapore Botanic Gardens. Last updated 16 November 2016.