Hymenophyllum digitatum (Sw.) Fosberg




Hymenophyllum digitatum (Sw.) Fosberg, Smithsonian Contr. Bot. 45: 1. 1980. – Trichomanes digitatum Sw., Syn. Fil.: 370, 422. 1806; Bedd., Handb. Ferns Brit. India: 39, f. 19. 1883; Copel., Philipp. J. Sci. 51: 159, pl. 7, f. 3 & 4. 1933; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 66. 1939; Holttum, Rev. Fl. Malaya ed. 1, 2: 94, f. 32. 1955 [‘1954’]. – Microtrichomanes digitatum (Sw.) Copel., Philipp. J. Sci. 67: 36. 1938; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 41. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 79, f. 5.6. 1979. – Crepidomanes digitatum (Sw.) K.Iwats., Acta Phytotax. Geobot. 35: 175. 1984; Tagawa & K.Iwats., Fl. Thailand 3: 613. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 69. 2000.


Rhizome long creeping, hairy, hairs caducous, pale brownish, up to 1 mm long. Stipes like rhizome, hairs caducous, terete, wingless except in the uppermost part, 2–4 cm long. Laminae rather irregular in outline, almost circular to oblong, every axis winged to form the segments just the same as the ultimate segments, to 5 cm long, 4 cm wide; ultimate segments linear-lanceolate, usually slightly falcate, round to obtuse at apex, 1.5–2 mm broad, usually 1 cm or so in length but occasionally elongate to the length of more than 2 cm, flat and setiferous or not at margin. Sori sunk in the apices of the ultimate segments; involucre cup-shaped with seemingly bilabiate mouth, 2 mm long including mouth, 1 mm diam., the mouth as broad as the ultimate segments.

Distribution in Thailand

PENINSULAR: Nakhon Si Thammarat, Yala.

Wider Distribution

Widely known in the Old World tropics: Madagascar, Mauritius, Peninsular Malaysia, Borneo, Java, Philippines and Samoa; type from ‘Ins. Franciae et Borboniae’.


On muddy rocks in dense tropical evergreen forest, known only on Khao Luang, locally abundant there.

Proposed IUCN Conservation Assessment

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

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