Family

Dryopteridaceae

Nomenclature

Polystichum biaristatum (Blume) T.Moore, Index Filic.: 86. 1858; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 342. 1941; Holttum, Dansk Bot. Ark. 23: 238. 1965; Tagawa & K.Iwats., SouthE. Asian Stud. 3(3): 86. 1965; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 94. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 337, f. 29.10 & 29.11. 1988; Boonkerd & Pollawatn, Pterid. Thailand: 161, 208. 2000. – Aspidium biaristatum Blume, Enum. Pl. Javae 164. 1828. – Polystichum aculeatum var. biaristatum (Blume) Bedd., Handb. Ferns Brit. India: 209. 1883.

Aspidium aculeatum auct. non (L.) Sw.: Hoss., Beih. Bot. Centralbl. 28(2): 363. 1911. – Polystichum aculeatum auct. non (L.) Schott: Holttum, Dansk Bot. Ark. 20: 30. 1961.

Description

Rhizome short, suberect; scales narrowly subtriangular, attenuate at apex, entire at margin, up to 25 by 4 mm, bicoloured, central portion shining black and tough, the margin brown to dark brown with ferrugineous margin. Stipes 30–40 cm long; scales at base of two kinds, one like those on rhizome, the other narrower, linear, up to 1 cm long, brown, toothed at margin, those on upper part linear, black with brown broader base. Laminae oblong-lanceolate, widest at middle, slightly narrowing towards base, acuminate at apex, 40–50 by 25–30 cm; rachis densely scaly throughout with linear black scales with brown broader base; pinnae more than 15 pairs, lower pinnae patent or slightly ascending, very shortly stalked, lanceolate, gradually acuminate at apex, broadly cuneate or subtruncate at base, up to 15 by 3 cm; basal acroscopic pinnules larger; pinnules rather close, oblong or gradually narrowing towards apex, falcate, acute and ending in sharp awns at apex, sessile, 15–20 by 5–8 mm, shallowly lobed at margin; veinlets a little raised on lower surface, minutely scaly; coriaceous, green. Sori arranged in one row at submarginal or medial part of pinnules; indusia pale brown, about 1 mm diam.

Distribution in Thailand

NORTHERN: Chiang Mai, Chiang Rai, Tak; NORTH-EASTERN: Loei; SOUTH-WESTERN: Kanchanaburi; SOUTH-EASTERN: Prachin Buri, Chanthaburi; PENINSULAR: Ranong.

Wider Distribution

Sri Lanka, N India, S China, Taiwan and Java.

Ecology

On humus-rich floor of dense evergreen forests at 900–1400 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. 4739, Kanchanaburi, Lam Khlong Ngu National Park (E).