Thelypteris dayi (Bedd.) B.K.Nayar & S.Kaur




Thelypteris dayi (Bedd.) B.K.Nayar & S.Kaur, Companion Handb. Ferns Brit. India: 59. 1974. – Nephrodium dayi Bedd., J. Bot. 25: 323. 1887 – Aspidium dayi (Bedd.) Bedd., J. Bot. 26: 4. 1888 – Lastrea dayi (Bedd.) Bedd., Suppl. Ferns Brit. Ind.: 54. 1892. – Metathelypteris dayi (Bedd.) Holttum in B.K.Nayar & S.Kaur, Companion Handb. Ferns Brit. India: 205. 1974. – Type: J.Day s.n., Peninsular Malaysia, Perak, March 1887 (K, barcode K000638046, lectotype designated by Holttum (Flora Malesiana, 1982)).

Thelypteris singalanensis auct. non (Baker) Ching: Tardieu & C.Chr., Fl. Indo-Chine 7(2): 365. 1941; Holttum, Rev. Fl. Malaya ed. 1, 2: 243, f. 138. 1955 [‘1954’]; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 63. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 399, f. 38.1–3. 1988. – Metathelypteris singalanensis auct. non (Baker) Ching: Boonkerd & Pollawatn, Pterid. Thailand: 225. 2000.


Rhizome short, erect; scales very sparse, linear, up to 8 by 0.2 mm, dark brown. Stipes stramineous, up to 60 cm long, scaly and hairy at base when young, glabrescent upwards. Laminae about 60 by 35 cm, pinnate-bipinnatifid; pinnae sessile, linear-lanceolate, caudate-acuminate at apex, up to 20 by 3 cm; rachis and costa densely hairy on upper surface, glabrous below; pinnules narrowly oblong, patent to falcate, up to 15 by 4.5 mm, entire, rounded to moderately acute at apex; softly papyraceous to papyraceous, green; veins pinnate, veinlets simple, forked, or triforked, glabrous. Sori dorsal on veinlets, in a medial row between costules and margin of pinnules; indusia thin, glabrous .

Distribution in Thailand

NORTHERN: Phitsanulok; SOUTH-WESTERN: Phetchaburi; PENINSULAR: Nakhon Si Thammarat.

Wider Distribution

Vietnam, Peninsular Malaysia, Sumatra, Borneo and W Java.


On mountain slopes in light shade or in evergreen forests at medium altitudes.

Proposed IUCN Conservation Assessment

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

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