Acrosorus friderici-et-pauli (Christ) Copel.


After Karl Friedrich Sarasin (1859-1942) and his cousin Paul Benedikt Sarasin (1856-1929)



Type Specimen Information

F. & P. Sarasin 760, Sulawesi ("Celebes"), G. Matinang (BAS, BM).


Acrosorus friderici-et-pauli (Christ) Copel., Philipp. J. Sci. 1(Suppl. 2): 159. 1906; Parris, Fl. Pen. Malaysia, Ser. I, Ferns & Lycoph. 1: 134. 2010. – Davallia friderici-et-pauli Christ, Verh. Naturf. Ges. Basel 11: 202. 1895. – Type: F. & P. Sarasin 760, Indonesia, Sulawesi, G. Matinang (isotype P).

Acrosorus triangularis Copel., Philipp. J. Sci., Sect. C, Botany 3: 347. 1909; Holttum, Rev. Fl. Malaya ed. 1, 2: 222, f. 122. 1955 [‘1954’]; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 62. 1967; Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 53. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 597, f. 59.4–5. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 289. 2000. – Polypodium triangulare Scort. ex Bedd., J. Bot. 25: 324, t. 278, f. 1. 1887, nom. illeg. non Polypodium triangulare G.F.Gmel. (1791); Bedd., Suppl. Ferns Brit. Ind.: 87. 1892.


Epiphytic. Rhizome short, suberect, bearing fronds in a tuft, usually also with old fronds, scaly; scales linear, up to 5 by 0.4 mm, brown or bright brown, with 3–6 rows of longitudinal cells, entire. Stipes indistinct or to 4 mm long, green to brown, winged to the very base, glabrous. Laminae linear, up to 5–20(–53) cm by 2–7(–9) mm, gradually narrowing towards both apex and base, deeply lobed almost to midrib; sterile lobes subtriangular, the acroscopic edges almost straight, nearly perpendicular to midrib, the basiscopic edges almost straight or slightly curved, forming about 45° to midrib, the apex moderately acute, 3–4 mm in both length and width; thinly leathery, glabrous or nearly so except on midrib, veins hardly visible, simple; fertile lobes at middle or apical portion of fronds, sometimes mixed with sterile ones, each bearing a sorus, circular to broadly elliptic in outline, deeply sunken in rimless pouches in the margin of the lamina, prominent on upper surface.

Distribution in Thailand

PENINSULAR: Surat Thani, Nakhon Si Thammarat, Yala.

Wider Distribution

Thailand, Vietnam, Peninsular Malaysia, Borneo, Philippines, Sulawesi and Maluku.


On mossy tree trunks in dense evergreen forests on ridges or sometimes lithophytic .  At medium or high altitudes.

Proposed IUCN Conservation Assessment

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

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