Abrodictyum obscurum (Blume) Ebihara & K.Iwats. var. obscurum

Family

Hymenophyllaceae

Nomenclature

Abrodictyum obscurum (Blume) Ebihara & K.Iwats., Blumea 51(2): 244. 2006. – Trichomanes obscurum Blume, Enum. Pl. Javae.: 227. 1828; Copel., Philipp. J. Sci. 51: 233, pl. 43–44. 1933; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 69. 1939; Holttum, Rev. Fl. Malaya ed. 1, 2: 108, f. 44. 1955 [‘1954’]; Holttum, Dansk Bot. Ark. 23: 229. 1965. – Selenodesmium obscurum (Blume) Copel., Philipp. J. Sci. 67: 81. 1938; Ching, Fl. Reipubl. Popularis Sin. 2: 191. 1959; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 44. 1967; Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 52. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 99. 1979. – Cephalomanes obscurum (Blume) K.Iwats., J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 13: 547. 1985; Tagawa & K.Iwats., Fl. Thailand 3: 615. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 68. 2000.

Trichomanes rigidum auct. non Sw.: Bedd., Handb. Ferns Brit. India: 44. 1883; Christ, Bot, Tidsskr. 24: 103. 1901.

Description

Terrestrial. Rhizome very short, creeping or ascending, bearing many wiry roots and stipes, covered with dark hairs, 1–1.2 mm diam. Stipes stiff, stramineous, wingless, covered with brownish hairs, the hairs dense at base, 0.7–1.3 mm in diameter, sometimes more than 10 cm long but often dwarfed. Fronds oblong-subdeltoid or oblong-ovate, gradually narrowing towards acute apices, broadly cuneate or subtruncate at base, the larger ones more than 15 cm long, 8 cm wide, tripinnatifid, or more finely dissected; rachis narrowly winged, pinnae with very short stalks, oblong-lanceolate, acute at apex, cuneate at base, up to 5 cm long, 1.5 cm wide; pinnules with several segments, the base decurrent to form narrow wings of costae; texture coarse, dark green in colour. Sori apical on apical segments, cup-shaped, 1.2 mm long, 1 mm diam., winged, the mouth truncate .

Distribution in Thailand

NORTH-EASTERN: Loei; CENTRAL: Nakhon Nayok; PENINSULAR: Ranong, Nakhon Si Thammarat, Trang, Satun, Yala.

Wider Distribution

Widely distributed in the tropics of the Old World.

Ecology

On wet sandy ground near streams in dense evergreen forest at high altitudes.

Proposed IUCN Conservation Assessment

Least Concern (LC). Widespread and not under any immediate known threat.

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