Polystichum biaristatum (Blume) T.Moore

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).

Habit

Habit

Rhizome

Rhizome

Venation

Venation

Lower surface of lamina

Lower surface of lamina

Lower surface of pinna with fertile pinnules

Lower surface of pinna with fertile pinnules

Pinnule

Pinnule

Pinnules

Pinnules

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