Onychium siliculosum (Desv.) C.Chr.

Family

Pteridaceae, subfamily Pteridoideae

Nomenclature

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.

Description

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.

Wider Distribution

India, SW China (Yunnan), Taiwan, Indochina, throughout Malesia to Polynesia.

Ecology

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).

Whole plant

Whole plant

Rhizome

Rhizome

Crozier

Crozier

Cross section through stipe

Cross section through stipe

Lamina from beneath

Lamina from beneath

Sori

Sori

Site hosted by the Royal Botanic Garden Edinburgh. Content managed by Stuart Lindsay, Gardens by the Bay, Singapore and David Middleton, Singapore Botanic Gardens. Last updated 16 November 2016.