Pteris phuluangensis Tagawa & K.Iwats.

Family

Pteridaceae, subfamily Pteridoideae

Nomenclature

Pteris phuluangensis Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 111, f. 7. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 248, f. 18.2. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 130. 2000; Newman et al., Checkl. Vasc. Pl. Lao PDR: 31. 2007.

Pteris sp. aff. P. grevilleana: Tagawa & K.Iwats., SouthE. Asian Stud. 5: 80. 1967.

Description

Rhizome short, erect, scaly at apex; scales about 3 by 0.5 mm at base, linear-subtriangular, dark brown to nearly black with entire, brown, thinner edges. Stipes shining, deep castaneous to purplish, puberulous or glabrescent, up to 35 cm long on fertile fronds and 25 cm on sterile ones. Frond dimorphic with taller fertile fronds; lamina oblong-subdeltoid, deeply bipinnatisect, 15–23 by 12–22 cm at base; lateral pinnae 2–3 pairs, opposite or nearly so, 7–10 by 2.5–3.5 cm, oblong in outline, caudately acuminate at apex with unlobed long segments up to 3 cm long, broadly cuneate at sessile base, sometimes bearing basal basiscopic projections up to 5 by 3 cm; rachis shining, deep castaneous to purplish, hardly hirsute, with spines on upper surface; ultimate segments linear, lobed almost to costa, falcate, round to moderately acute at apex, serrate at margin, up to 30 by 6 mm, thinly papyraceous; veins forked, hardly visible on both surfaces, glabrous. Sori continuous along margin of ultimate segments except at sinus and towards apex; indusia thin, pale, up to 0.1 mm broad, irregular at margin .

Distribution in Thailand

NORTH-EASTERN: Loei.

Wider Distribution

Endemic in Thailand.

Ecology

On rather dry slopes in dry evergreen forests at about 800 m alt. Pteris phuluangensis is endemic to Loei.

Proposed IUCN Conservation Assessment

Least Concern (LC). Although this species is only known from Phu Luang Wildlife Sanctuary and its exact Area of Occupancy is unknown this area is well protected and there are no known threats to the population(s).

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