Adiantum edgeworthii Hook.

Etymology

According to Holttum (1954), the botanical name, Adiantum (unwetted) refers to the way in which water-drops run off the surface of the pinnae without wetting them.

Family

Adiantum edgeworthii Hook.

Nomenclature

Adiantum edgeworthii Hook., Sp. Fil. 2: 14, t. 81B. 1851; Bedd., Suppl. Ferns Brit. Ind.: 17. 1892; Ching, Icon. Filic. Sin. 3: t. 139. 1935; Ching, Acta Phytotax Sin. 6: 315. 1957; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 109. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 210, f. 16. 4. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 98, 117. 2000. – Adiantum caudatum var. edgeworthii (Hook.) Bedd., Handb. Ferns Brit. India: 84. 1883.

Description

Lithophytic. Rhizome short, erect, scaly at apex; scales narrow, 3–4 mm long, entire, bicoloured with black central portion and dark brown edge. Stipes up to 13 cm long, castaneous to bright blackish-purple, glabrous except scaly lower portion; scales on stipe like those on rhizome but concolorous brown. Laminae linear, simply pinnate, gradually narrowing upwards, up to 20 by 2 cm; rachis perfectly glabrous or with only occasional thin scale, usually prolonged, leafless on upper part, rooting at tip; lower pinnae hardly reduced; larger pinnae sessile, half-crescent-shaped to nearly parallelogram-shaped, round to moderately acute at apex, lower margin round, upper margin straight and lobed, inner edge straight, forming narrow cuneate base with lower margin, up to 10 by 5 mm, upper margin lobed to about 1/3 of width of pinnae, forming distinct sinus; lobes round, moderately acute to subtruncate at slightly toothed apex; papyraceous to softly chartaceous, perfectly glabrous on both surfaces; veins rather indistinct. Sori on apices of lobes, reflexed flaps circular or elongate, glabrous .

Distribution in Thailand

NORTHERN: Chiang Mai.

Wider Distribution

NE India, Upper Burma, China (north to Manchuria), Vietnam, Taiwan, Philippines, Timor, and northwards to S Japan.

Ecology

On muddy rocks in semi-shade or evergreen forests at 1600–1750 m alt.

Proposed IUCN Conservation Assessment

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

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