Family

Pteridaceae, subfamily Cheilanthoideae

Nomenclature

Cheilanthes tenuifolia (Burm.f.) Sw., Syn. Fil.: 129, 332. 1806; Bedd., Handb. Ferns Brit. India: 92. 1883; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 173. 1940; Holttum, Rev. Fl. Malaya ed. 1, 2: 590, f. 347. 1955 [‘1954’]; Holttum, Dansk Bot. Ark. 20: 33. 1961; Holttum, Dansk Bot. Ark 23: 243. 1965; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 108. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 201. 1985; Tagawa & K.Iwats., Fl. Thailand 3: 617. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 99, 100, 122. 2000. – Trichomanes tenuifolium Burm.f., Fl. Indica: 237. 1768. – Cheilosoria tenuifolia (Burm.f.) Trevis., Atti Reale Ist. Veneto Sci. Lett. Arti 5(3): 579. 1877.

Description

Rhizome short, ascending, covered with scales; scales light brown, very narrow, entire, 3–4 mm long. Stipes castaneous, polished, slightly swollen and densely scaly at base, sparsely and minutely scaly upwards, 10–25 cm long, grooved on adaxial surface. Frond dimorphic; sterile lamina smaller, with stipe 8–12 cm in length, deltoid in outline. Fertile lamina tripinnate, or the larger quadripinnatifid, subdeltoid in outline, up to 20 by 8 cm; rachis and pinna-rachis scaly, grooved on upper surface; pinnae ten or more pairs, basal ones the largest, subtriangular, acute at apex; middle pinnae oblong-subtriangular; larger pinnules pinnatisect with a few pairs of lobes and a large terminal one, terminal lobes of pinnules like terminal pinnae and pinnules, oblong, round at apex, 5–10 by c. 3 mm, entire; ultimate lobes round or oval, 2–4 mm long, up to 1.5 mm broad, papyraceous, green; veins all free, obscure. Sporangia confined to the end of veins but appearing continuous at margin of lobes, when young protected by reflexed margin of lobes, edges uneven, pellucid.

Distribution in Thailand

NORTHERN: Mae Hong Son, Chiang Mai, Lamphun, Lampang, Phrae, Tak, Phitsanulok; EASTERN: Ubon Ratchathani; CENTRAL: Nakhon Nayok; SOUTH-EASTERN: Chanthaburi, Trat; PENINSULAR: Chumphon, Surat Thani, Phangnga, Krabi, Trang, Satun, Songkhla, Yala.

Distribution in Laos

Champasak.

Distribution in Cambodia

Kampot, Kompong Speu, Pursat

Wider Distribution

Tropics of Asia and Oceania, from India and S China through Malesia to Polynesia, Australia and New Zealand.

Ecology

On rather dry clayey banks of paths in mixed forests at low altitudes.

Proposed IUCN Conservation Assessment

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

Notes

Cheilanthes is a difficult genus that needs more taxonomic research.

Voucher specimens - Thailand

Middleton et al. 4931, Chiang Mai, Road to Ban Ung from Ban Mae Na Chon (E); Middleton et al. 5192, Ubon Ratchathani, Phu Chong Nayoi National Park (E); Maxwell 06-549, Krabi (CMU, QBG).

Voucher specimens - Laos

Maxwell 98-953, Champasak (CMU).