Lygodium circinnatum (Burm.f.) Sw.

Family

Lygodiaceae

Nomenclature

Lygodium circinnatum (Burm.f.) Sw., Syn. Fil.: 153. 1806; Bedd., Handb. Ferns Brit. India: 455, f. 281. 1883; Holttum, Rev. Fl. Malaya ed. 1, 2: 55, f. 9. 1955 [‘1954’]; Holttum, Fl. Males., Ser. II, Pterid. 1: 59, f. 5d & 14. 1959; Tagawa & K.Iwats., Acta Phytotax. Geobot. 23: 51. 1968; Tagawa & K.Iwats., Fl. Thailand 3: 65. 1979; Boonkerd & Pollawatn, Pterid. Thailand: 82. 2000. – Ophioglossum circinnatum Burm.f., Fl. Ind.: 228. 1768.

Lygodium conforme C.Chr., Bull. Mus. Natl. Hist. Nat. II. 6: 104. 1934; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 35. 1939. – Type: Colani 2983, Vietnam, Lang Nac (BM; P x3, US).

Description

Rhizome shortly creeping, densely covered with blackish hairs. Fronds large, climbing to several metres; stipes brownish stramineous, hairy on the lower part, narrowly winged on upper part; rachis 2–5 mm diam., glabrous, with very short wings (or ridges) or not; primary rachis-branches very short, less than 2 mm long, the apex dormant and somewhat sunken, covered with pale brownish hairs; secondary rachis-branches 2–4 cm long, sometimes branching once dichotomously; sterile leaflets with 2–7 lobes palmately divided with cuneate base, the lobes gradually narrowing towards acute apex, entire at margin, up to 20 cm long, more than 2 cm broad, sometimes fertile on the upper part; lamina softly papyraceous, glabrous except sparsely hairy main veins, sometimes warty; fertile leaflets similar in the branching system to the sterile ones, narrower or not, up to 1.6 cm broad (excluding the sporangia-bearing lobes). Sporangia-bearing lobes protruding, numerous at margin of tertiary leaflets, 2–5 mm long, about 1.2 mm broad; indusia glabrous .

Distribution in Thailand

SOUTH-EASTERN: Chanthaburi; PENINSULAR: Surat Thani, Phangnga, Nakhon Si Thammarat, Satun, Yala, Narathiwat.

Distribution in Laos

Luang Phrabang.

Wider Distribution

Sri Lanka, NE India, throughout Malesia to Micronesia and the Solomons.

Ecology

In light shade in tropical evergreen forest at low or medium altitude.

Proposed IUCN Conservation Assessment

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

Notes

This is a very variable species .  Larger forms have been recognised as Lygodium conforme but there would appear to be a continuum of variation from the smaller to the larger forms.  Dy Phon (2000) records Lygodium conforme a synonym of Lygodium circinnatum, for Cambodia.  We have seen no material and her description of "a small slightly climbing fern" usually would not to apply to this species.  We are unclear what species it should be.

Uses. – Stems used in making handbags and hats.

Voucher specimens - Thailand

Larsen et al. 32007, Chanthaburi, Nam Tok Taka Mao (P); Middleton et al. 5353, Satun, Beside road 2 km from Thale Ban National Park (E); Sangkhachand 1399, Yala, Bannang Sata (P).

Habit

Habit

Young pinnae

Young pinnae

Lamina

Lamina

Rachis, primary rachis branch (extremely short) and two secondary rachis branches (ending in lamina)

Rachis, primary rachis branch (extremely short) and two secondary rachis branches (ending in lamina)

Secondary rachis branch and lamina

Secondary rachis branch and lamina

Mature sori

Mature sori

Young sori

Young sori

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