Onychium siliculosum (Desv.) C.Chr.
Pteridaceae, subfamily Pteridoideae
Onychium siliculosum (Desv.) C.Chr., Index Filic.: 468. 1906; C.Chr., Bot. Tidsskr. 32: 347. 1916; Ching, Lingnan Sci. J. 13: 495. 1934; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 169, f. 20.4. 1940; Holttum, Dansk Bot. Ark. 20: 32. 1961; Holttum, Dansk Bot. Ark 23: 243. 1965; Tagawa & K.Iwats., Fl. Thailand 3: 195. 1985; Boonkerd & Pollawatn, Pterid. Thailand: 102, 124. 2000. – Pteris siliculosa Desv., Berl. Mag. 5: 324. 1811.
Onychium auratum Kaulf., Enum. Filic.: 144. 1824; Bedd., Handb. Ferns Brit. India: 96, f. 49. 1883; Christ, Bot. Tidsskr. 24: 106. 1901.
Rhizome short, ascending or creeping, densely covered with scales; scales linear, 5–7 mm long, thin but firm, entire, concolorously brown. Stipes stramineous, scaly at base, up to 30 cm long. Laminae quadripinnate, oblong-ovate, acuminate at apex, round at base, up to 35 by 10–25 cm; rachis glabrous, grooved on upper surface; lateral pinnae gradually reducing in size upwards, lower ones oblong-subdeltoid, caudately acuminate at apex, stalked at base, up to 20 by 8 cm; pinnules and secondary pinnules distinctly stalked; segments (4th divisions in lower pinnae) spathulate, oblique, sometimes slightly falcate, acute at apex, 6–10 by 1.5–2.5 mm, with a few lobes; ultimate lobes narrow, acute, entire, uninervate in sterile ones; herbaceous, perfectly glabrous on both surfaces, green to yellow green. Fertile segments larger, 10–30 by 1.5–2.5 mm, lower side covered by sporangia, completely protected by reflexed marginal flaps, densely coated with lemon yellow wax.
Distribution in Thailand
NORTHERN: Mae Hong Son, Chiang Mai, Lamphun; NORTH-EASTERN: Phetchabun; SOUTH-WESTERN: Kanchanaburi; SOUTH-EASTERN: Trat; PENINSULAR: Phangnga.
Distribution in Laos
Hua Phan, Xieng Khouang.
India, SW China (Yunnan), Taiwan, Indochina, throughout Malesia to Polynesia.
On rather dry banks of new roads in open areas at 800–1000 m alt.
Proposed IUCN Conservation Assessment
Least Concern (LC). This species is widespread and not under any known threat.
Voucher specimens - Thailand
Prakawowanakit s.n., Mae Hong Son, Mae Sarieng, Hui Sai (P); Middleton et al. 4933, Chiang Mai, Road to Ban Ung from Ban Mae Na Chon (E); Middleton et al. 4745, Kanchanaburi, Khao Laem National Park (E); Larsen & Larsen 33422, Phangnga, Khao Paw Ta Luang Keo (P).
Voucher specimens - Laos
Poilane 2196, Xieng Khouang (P).
Cross section through stipe
Lamina from beneath
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