Cyclosorus validus (Christ.) Ching

Family

Thelypteridaceae

Nomenclature

Cyclosorus validus (Christ) Ching, Bull. Fan Mem. Inst. Biol. 8: 221. 1938; C.Chr. & Tardieu, Notul. Syst. 7: 78. 1938; C.Chr. & Tardieu, Fl. Indo-Chine 7(2): 398. 1941. – Dryopteris valida Christ, J. Bot. 21: 230, 261. 1908. – Thelypteris valida (Christ) Tagawa & K.Iwats., Acta Phytotax. Geobot. 22: 101. 1967; SouthE. Asian Stud. 5: 67. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 420. 1988. – Sphaerostephanos validus (Christ) Holttum, Kew Bull. 34: 224. 1979.

Dryopteris hirtisora C.Chr., Contr. U.S. Natl. Herb. 26: 277, 330. 1931. – Cyclosorus hirtisorus (C.Chr.) Ching, Bull. Fan Mem. Inst. Biol. 8: 221. 1938; Boonkerd & Pollawatn, Pterid. Thailand: 223. 2000. – Thelypteris hirtisora (C.Chr.) K.Iwats., J. Jap. Bot. 38: 314. 1963; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 66. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 418, f. 43.1–2. 1988. – Sphaerostephanos hirtisorus (C.Chr.) Holttum, Kew Bull. 34: 223. 1979.

Cyclosorus acuminatus auct. non (Houtt.) Nakai ex H.Ito: Holttum, Dansk Bot. Ark. 20: 22. 1961.

Description

Rhizome long creeping, about 6(–10) mm diam.; scales up to 10 by 1.5 mm, brown, hairy. Stipes 20–59 cm long, scaly at base, hirsute throughout. Laminae oblong or subrectangular with a long terminal pinna, up to 80 by 50 cm; lower pinnae hardly reduced, or lower one or two pairs slightly reduced and deflexed, larger pinnae patent to slightly ascending, about 12 pairs, nearly straight, shortly stalked, linear, gradually narrowing to long-acuminate apex, round to broadly cuneate at base, up to 26.5 by 2.5 cm, lobed more than 1/3 way towards costa; segments subdeltoid, oblique, acute at apex; softly papyraceous, hirsute on surface, more than 2 pairs of lower veinlets truly anastomosing below callous-sinus. Sori medial, round; indusia rather small, hairy, persistent but usually under sporangia in matured sori; sporangia setose .

Distribution in Thailand

NORTHERN: Chiang Mai, Chiang Rai, Tak; NORTH-EASTERN: Phetchabun, Loei; SOUTH-WESTERN: Kanchanaburi, Phetchaburi.

Distribution in Laos

Xieng Khouang.

Distribution in Cambodia

Kampot.

Wider Distribution

SW China, Upper Burma and Indochina.

Ecology

On rather dry slopes in mixed or evergreen forests at medium altitudes at 600–1300 m alt.

Proposed IUCN Conservation Assessment

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

Notes

We are following the species concept of Tardieu-Blot & Christensen in Fl. Indo-Chine. The different justifications for recognising two species made by both Tagawa & Iwatsuki in the Flora of Thailand and by Holttum in his revision (Kew Bulletin 34: 221–232. 1979) need further investigation but we choose to recognise a broader species concept here.

Voucher specimens - Thailand

Maxwell 08-50, Chiang Mai (QBG).

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