Family

Pteridaceae, subfamily Cheilanthoideae

Nomenclature

Cheilanthes fragilis Hook., Fil. Exot. : t. 96. 1859; Bedd., Handb. Ferns Brit. India: 91. 1883; Tagawa & K.Iwats., Acta Phytotax. Geobot. 25: 19. 1971; Tagawa & K.Iwats., Fl. Thailand 3: 203, f. 15.3. 1985; Tagawa & K.Iwats., Fl. Thailand 3: 617. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 120. 2000. – Type: Moulmein, Parish 93 (K?; possible duplicate E).

Description

Rhizome short, erect, scaly; scales gradually narrowing towards acuminate apex, about 4 mm long, up to 0.5 mm broad, brown, central portion sometimes stiff and darker, entire. Stipes castaneous or darker, up to 10 cm long, scaly near base, densely pubescent throughout, hairs coarse, multicellular, 2–5 cells long, patent, dark. Laminae bipinnatifid, oblong-lanceolate or narrower, up to 31 by 7.5 cm in fertile, up to 15 cm by 7 cm in sterile fronds; rachis pubescent throughout, grooved on upper surface; pinnae alternate, sessile, narrowly elliptic, acuminate at apex, subtruncate at base, or narrowly oblanceolate with moderately acute apex, up to 4 by 1 cm; costa castaneous, green in distal portion, pubescent or glabrescent; pinnules close to somewhat distant, patent to oblique, oblong, round to moderately acute at apex, adnate at base, entire or slightly waved at margin, softly papyraceous, sparsely hairy at margin and on lamina above, sparsely hairy or glabrous beneath; veinlets simple, hardly visible. Sori at apex of veinlets, protected by thin reflexed flaps.

Distribution in Thailand

NORTHERN: Chiang Mai, Nan, Tak.

Wider Distribution

Burma.

Ecology

On limestone rocks on ridges of hills in teak jungles at 750–930 m alt.

Proposed IUCN Conservation Assessment

Data Deficient (DD). This species is known from just a small number of karst limestone sites in Thailand, mostly not in protected areas, but its distribution in Burma is unknown.

Notes

Cheilanthes is a difficult genus that needs more taxonomic research.

Voucher specimens - Thailand

Middleton et al. 5597, Nan, Tham Sakoen (E); Middleton et al. 4845, Tak, Wat Tham Inthanin (E); Middleton et al. 4859, Tak, limestone hill behind Phawo Shrine (E).