Lygodium flexuosum (L.) Sw.

Family

Lygodiaceae

Nomenclature

Lygodium flexuosum (L.) Sw., Schrad. J. Bot. 1800(2): 106. 1801; Bedd., Handb. Ferns Brit. India: 457, f. 283. 1883; Hosseus, Beih. Bot. Centralbl. 28(2): 367. 1911; C.Chr., Contr. U.S. Natl. Herb. 26: 329. 1931; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 38. 1939; Holttum, Rev. Fl. Malaya ed. 1, 2: 57, f. 11. 1955 [‘1954’]; Holttum, Fl. Males., Ser. II, Pterid. 1: 53, f. 9e & f. 1959; Holttum, Dansk Bot. Ark. 20: 15. 1961; Holttum, Dansk Bot. Ark. 23: 228. 1965; Seidenf., Nat. Hist. Bull. Siam Soc. 19: 85. 1958; Ching, Fl. Reipubl. Popularis Sin. 2: 111. 1959; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 35. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 62. 1979; Boonkerd & Pollawatn, Pterid. Thailand: 82. 2000; Dy Phon, Dictionary of Plants used in Cambodia: 411. 2000; Newman et al., Checkl. Vasc. Pl. Lao PDR: 28. 2007; Leti et al., Fl. Photogr. Cambodge 555. 2013. – Ophioglossum flexuosum L., Sp. Pl. 1063. 1753.

Lygodium flexuosum var. altum auct. non C.B.Clarke: Tardieu & C.Chr., Botul. Syst. (Paris) 5: 168. 1936; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 39. 1939.

Lygodium dichotomum auct. non Sw.: Ostenf., Bull. Herb. Boiss. II. 5: 721. 1905.

Lygodium giganteum auct. non Tagawa & K.Iwats.: Newman et al., Checkl. Vasc. Pl. Lao PDR: 28. 2007.

Description

Rhizome short, densely covered with dark brown hairs. Fronds climbing, usually several metres tall; stipes 50 cm or more long, stramineous with dark brown basal portion, minutely hairy or glabrescent, narrowly winged on the upper part; rachis winged throughout, puberulous on the upper surface between the wings, stramineous; primary rachis-branches very short, up to 3 mm, the apex dormant, covered with downy pale brown hairs; secondary rachis-branches pinnate to bipinnate, oblong to subdeltoid in outline, usually with acute apex, 10–25 cm long, 7–12 cm wide; tertiary leaflets of lower branches palmate, the base distinctly cordate, those of the distal part of plants trilobed, hastate, or simple, the base of lobes distinctly cordate, the ultimate lobe up to 15 cm long, 2.5 cm broad, acute to moderately acute at apex, distinctly serrate at margin, with distinct stalk at base, the stalks up to 1 cm long, winged, sparsely hairy, without articulation or with a small thickening at base of laminar part; lamina herbaceous, glabrous above, lamina below between veins with minute glandular hairs but appearing glabrous or with the glandular hairs and larger stiff hairs, veins with the larger hairs. Sporangia-bearing lobes protruding at margin of tertiary leaflets, up to 1 cm long, 1.5 mm broad; indusia glabrous .

Distribution in Thailand

NORTHERN: Mae Hong Son, Chiang Mai, Chiang Rai, Nan, Lamphun, Lampang, Phrae, Tak, Phitsanulok; NORTH-EASTERN: Loei, Khon Kaen; EASTERN: Nakhon Ratchasima; SOUTH-WESTERN: Kanchanaburi, Prachuap Khiri Khan; CENTRAL: Bangkok, Saraburi, Nakhon Nayok; SOUTH-EASTERN: Prachin Buri; PENINSULAR: Chumphon, Phangnga, Nakhon Si Thammarat.

Distribution in Laos

Champasak, Luang Phrabang, Vientiane.

Distribution in Cambodia

Kampot, Koh Kong, Mondulkiri, Pursat, Ratanakiri.

Wider Distribution

Sri Lanka, N India, SW and S China, Hongkong, Ryukyus and Taiwan, southwards to Queensland through Malesia and Melanesia.

Ecology

Climbing on shrubs or on branches of tall trees in open areas or in deciduous or mixed forest, fairly common at low or medium altitudes.

Proposed IUCN Conservation Assessment

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

Notes

We have been unable to find the Lao specimen identified as Lygodium flexuosum var. altum by Tardieu & Christensen in Fl. Indo-Chine.  The other material cited by them under this variety is clearly just Lygodium flexuosum but we refrain from any comment on whether the variety is a synonym pending further research.  Medicinal properties are reported from Cambodia (Dy Phon, 2000).

Voucher specimens - Thailand

Larsen et al. 645, Phitsanulok, Tung Salaeng Luang (P).

Voucher specimens - Laos

Maxwell 98-900, Champasak (CMU); Munzinger 184, Champasak, Vat Phou (P); Dupuy 277, Luang Prabang (P); Vidal 969B, Vientiane, km20-22 route de Paksane (P).

Voucher specimens - Cambodia

Geoffray 55bis, Kampot (P); Long et al. CL378, CL381 & CL471, Mondulkiri (P); Schnell 10230 bis, Mondulkiri (P); Martin 1322, Pursat, Dak Bat (P); David et al. CL713, Ratanakiri, Veal Thmor Longley (P); Martin 1465bis, Ratanakiri, Ban Lang (P).

Habit

Habit

Pinna

Pinna

Undersurface of pinna and marginal sori

Undersurface of pinna and marginal sori

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