Family

Hymenophyllaceae

Nomenclature

Hymenophyllum polyanthos (Sw.) Sw., Schrad. J. Bot. 1800(2): 102. 1801; Bedd. Handb. Ferns Brit. India: 30. 1883; Copel., Philipp. J. Sci. 64: 97, pl. 46 & 47. 1937; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 54. 1939; Holttum, Rev. Fl. Malaya ed. 1, 2: 81, f. 23. 1955 [‘1954’]; Holttum, Dansk Bot. Ark. 20: 17. 1961; Holttum, Dansk Bot. Ark. 23: 229. 1965; Seidenf., Nat. Hist. Bull: Siam Soc. 19: 85. 1958; Tagawa & K.Iwats., Fl. Thailand 3: 611. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 30, 74. 2000. – Trichomanes polyanthos Sw., Prod. Fl. Ind. Occ.: 137. 1788. – Mecodium polyanthos (Sw.) Copel., Philipp. J. Sci. 67: 19. 1938; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 37. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 70. 1979.

Hymenophyllum osmundoides Bosch, Ned. Kruidk. Arch. 5(3): 164. 1863. – Mecodium osmundoides (Bosch) Ching, Fl. Reipubl. Popularis Sin. 2: 147, pl. 10, f. 7-11. 1959; Ching & S.-K.Wu in C.-Y.Wu, Fl. Xizang. 1: 49. 1983.

Description

Rhizome slender, less than 0.2 mm diam., with hairy rootlets. Stipes (1–) 2–5.5 cm long, wingless except the uppermost part, sparsely hairy especially in the younger parts, the rootlets densely hairy, the hairs brown, up to 1 mm long. Laminae very variable both in size and form, lanceolate, oblong-lanceolate, oblong or subdeltoid, acute to acuminate at apex, 3–13.8 cm long, 1.5–8 cm wide, usually tripinnatifid, light green, herbaceous; rachis winged throughout, wings very narrow, entire, flat; pinnae less than 10 in pairs, the largest one in the middle of the frond, reducing in size both upward and downward, the larger ones oblong-subdeltoid or oblong-lanceolate, somewhat falcate; ultimate segments linear or narrowly lanceolate, round to obtuse at apex, the margin entire and flat, usually about 0.8 mm broad. Sori scattered usually on the upper parts of fronds; involucre ovate, subdeltoid or rarely reniform, about 1 mm in length, usually longer than the breadth, deeply divided; lips round or moderately acute, entire or slightly crenate; receptacles clavate, included . Cell walls thin, straight, rarely rather thick.

Distribution in Thailand

NORTHERN: Chiang Mai, Phitsanulok; NORTH-EASTERN: Loei; SOUTH-WESTERN: Kanchanaburi; CENTRAL: Nakhon Nayok; SOUTH-EASTERN: Chanthaburi, Trat; PENINSULAR: Chumphon, Surat Thani, Nakhon Si Thammarat.

Distribution in Laos

Khammouane.

Distribution in Cambodia

Kampot

Wider Distribution

Tropics or subtropics throughout the world, north to central Japan.

Ecology

Epiphytic on tree trunks or on mossy rocks in light or deep shade, common at medium or higher altitudes.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is common and widespread.

Notes

This is a very widespread and variable species with many synonyms throughout its range.

Voucher specimens - Thailand

Middleton et al. 4897, Chiang Mai, Doi Inthanon National Park (E); Middleton et al. 5072, 5080 & 5081, Phitsanulok, Phu Hin Rong Kla National Park; Middleton et al. 5155, Loei, Phu Luang Wildlife Sanctuary (E).