Family

Lindsaeaceae

Nomenclature

For the species

Lindsaea orbiculata (Lam.) Mett. ex Kuhn, Ann. Mus. Bot. Lugduno-Batavi 4: 279. 1869; Bedd., Handb. Ferns Brit. India: 75. 1883; Christ, Bot. Tidsskr. 24: 110. 1901; C.Chr., Bot. Tidsskr. 32: 345. 1916; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 125. 1939; Ching, Fl. Reipubl. Popularis Sin. 2: 264. 1959; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 74. 1967; Kramer, Fl. Males., Ser. II, Pterid. 1: 206, f. 15. 1971; Kramer, Gard. Bull. Singapore 26: 21. 1972; Tagawa & K.Iwats., Fl. Thailand 3: 135. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 94. 2000. – Adiantum orbiculatum Lam., Encycl. (Lamarck) 1: 41. 1783. – Schizoloma orbiculatum (Lam.) Kunh, Chaetopterides: 346. 1882; Holttum, Rev. Fl. Malaya ed. 1, 2: 344, f. 199. 1955 [‘1954’]; Holttum, Dansk Bot. Ark. 20: 25. 1961.

For var. commixta

Lindsaea orbiculata (Lam.) Mett. ex Kuhn var. commixta (Tagawa) K.U.Kramer, Fl. Males., Ser. II, Pterid. 1: 207. 1971; Kramer, Gard. Bull. Singapore 26: 22, f. 8. 1972; Tagawa & K.Iwats., Fl. Thailand 3: 137. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 94. 2000. – Lindsaea commixta Tagawa, Acta Phytotax. Geobot. 6: 37, f. 3, H–J. 1937; Ching, Fl. Reipubl. Popularis Sin. 2: 268. 1959. – Lindsaea tenera Dryand . var. commixta (Tagawa) Iwatsuki, Acta Phytotax. Geobot. 19: 6. 1961.

Description

Rhizome short creeping, about 1.5 mm diam., scaly throughout; scales linear, up to 2 mm long, 2–3 rows of cells at base, brown. Frond dimorphic. Sterile frond: stipe up to 4 cm long, brown to castaneous, paler above, grooved on upper surface, round beneath; lamina simply pinnate, 4–6 cm long, up to 2 cm wide; pinnae sessile, up to 10 pairs, almost fan-shaped, lower and inner edges straight or a little bending, meeting at right angles, the other edges round, serrate at margin; texture herbaceous, veins all free, distinct on both surfaces. Fertile frond: stipe much longer, up to 30 cm long; lamina narrowly subtriangular, simply pinnate or bipinnate with a few lateral pinnae, altogether up to 34 pairs of lateral pinnae, up to 28.5 cm long, up to 19 cm wide at base; lateral pinnae very shortly stalked, simply pinnate with up to 10 pairs of almost fan-shaped pinnules; terminal pinnae like the laminae of simply pinnate fronds; lower pinnules of terminal pinnae almost fan-shaped, upper ones oblong. Sori continuous along upper and outer edges; indusia firm , not reaching the edge.

Key to the varieties in Thailand

1. Fertile frond pinnate, or bipinnate with a few lateral pinnae …var. orbiculata
1. Fertile frond bipinnate nearly to the apex …var. commixta

Distribution in Thailand

Var. orbiculata

EASTERN: Chaiyaphum; CENTRAL: Nakhon Nayok; SOUTH-EASTERN: Trat; PENINSULAR: Surat Thani, Trang.

Var. commixta

NORTHERN: Chiang Mai; NORTH-EASTERN: Loei; SOUTH-EASTERN: Chanthaburi.

Distribution in Cambodia

Var. orbiculata

Kampot

Wider Distribution

Var. orbiculata

NE India, S China, Burma, Indochina, W and Central Malesia, extending north to S Japan through Taiwan and the Ryukyus.

Var. commixta

Sri Lanka, Himalayas, Burma, S China, Indochina, Taiwan, northwards to S Japan and southwards to the Philippines and Java.

Ecology

Var. orbiculata

On clayey slopes, often on banks of rivers in light shade or in evergreen forests, 0–800 m alt.

Var. commixta

Terrestrial on rather dry clayey ground in evergreen forests at medium altitudes, 900–1300 m alt.

Similar species

Lindsaea chienii Ching

Proposed IUCN Conservation Assessment

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

Notes

This species is very similar to Lindsaea chienii . We are doubtful they are separate species . This has also been discussed by Kramer, Fl. Males., Ser. II, Pterid. 1: 207. 1971.

Voucher specimens - Thailand

Var. orbiculata - Middleton et al. 4668, Chanthaburi, Khao Khitchakut National Park (E, P); Charoenphol et al. 5082, Trat, Ko Kut (P).

Var. commixta - Van Beusekom et al. 4545, Loei, Phu Kradung (P).