Asplenium tenerum G.Forst.

Family

Aspleniaceae

Nomenclature

Asplenium tenerum G.Forst., Prod.: 80. 1786; Bedd., Handb. Ferns Brit. India: 147, f. 74. 1883; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 226. 1940; Holttum, Rev. Fl. Malaya ed. 1, 2: 432. 1955 [‘1954’]; Sledge, Bull. Brit. Mus. (Nat. Hist.) Bot. 3: 253. 1965; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 86. 1967; Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 55. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 273. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 145, 178. 2000.

Asplenium tenerum var. retusum auct. non C.Chr.: Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 50. 1968.

Description

Epiphytic or lithophytic, rarely terrestrial. Rhizome short, ascending, up to 5 mm diam.; scales narrowing from base towards long-acuminate apex, about 5 by 1.2 mm, dark brown, clathrate, the edges bearing long projections. Stipes up to 15 cm long, dark green to dark brown, scaly throughout with smaller scales or glabrescent. Laminae pinnate, usually widest at base, acuminate at apex, up to 27 by 8.5 cm; rachis winged throughout, minutely scaly when young, proliferous; lateral pinnae about 20 pairs, patent to slightly ascending, falcate, acuminate at apex, auricled and subtruncate at acroscopic base and subdimidiate to narrowly cuneate at basiscopic base, regularly serrate with a single veinlet in each tooth, up to 5 by 1.5 cm, the upper ones smaller; chartaceous, green, glabrescent; costa raised above, veins visible on both surfaces, simple or basal acroscopic ones forked; crenae at margin oblique, rounded at apex, one-nerved, about 2 by 1.3 mm. Sori elongate along veins, up to 4 mm long, from near costa to below sinus; indusia thin but persistent , up to 0.8 mm broad.

Distribution in Thailand

NORTHERN: Phitsanulok; SOUTH-WESTERN: Phetchaburi, SOUTH-EASTERN: Chanthaburi; PENINSULAR: Surat Thani, Nakhon Si Thammarat, Trang, Yala, Narathiwat.

Distribution in Cambodia

Kampot, Kompong Chhnang.

Wider Distribution

Sri Lanka and S India to Polynesia, north to Vietnam and Taiwan.

Ecology

On mossy tree-trunks or on rocks in dense evergreen forests at medium altitudes (500– 1100 m).

Proposed IUCN Conservation Assessment

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

Voucher specimens - Cambodia

Pierre 5805, Kampot, Cam Chay (P); Poilane 28763, Kompong Chhnang, Phnom Chom (P).

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