Family

Dennstaedtiaceae

Nomenclature

Pteridium aquilinum (L.) Kuhn in Deck., Reis. Ost-Afr. 3(3): 11. 1879; C.Chr., Contr. U.S. Natl. Herb. 26: 333. 1931; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 136. 1939; R.M.Tryon, Rhodora 43: 12. 1941; Holttum, Rev. Fl. Malaya ed. 1, 2: 389, f. 225. 1955 [‘1954’]; Holttum, Dansk Bot. Ark. 20: 26. 1961; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 78. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 125, f. 9.4 & 9.6. 1979; Newman et al., Checkl. Vasc. Pl. Lao PDR: 26. 2007. – Pteris aquilina L., Sp. Pl.: 1075. 1753; Bedd., Handb. Ferns Brit. India: 115. 1883.

Description

Rhizome long creeping, covered with fine pale brown hairs. Stipes long, more than 1 m long, thick, dark brown to black in hypogeal parts, stramineous upwards, densely covered with pale brown hairs; lamina tripinnate to quadripinnatifid at base, the apex growing for a considerable period, up to 1 m or more both in length and width; rachis, costae and costules grooved on upper surface, the grooves decurrent to those in the next higher order; basal pair of pinnae larger, almost comparable with rest of lamina in size, up to 70 cm long, 40 cm wide, or rather narrower; ultimate leaflets small and narrow, subcoriaceous, usually covered with pale brown hairs, veins free, forked, raised beneath, hairy. Sori linear, submarginal, the apices of veins joined by vascular commissure, thus forming long continuous receptacles; indusia formed in two parts, one consisting of the thin reflexed edge of the leaflets, the other thin, almost transparent membrane attached just below the receptacles.

Distribution in Thailand

NORTHERN: Chiang Mai, Chiang Rai, Lamphun, Phitsanulok; NORTH EASTERN: Phetchabun, Loei.

Distribution in Laos

Unspecified.

Distribution in Cambodia

Kompong Speu, Mondulkiri.

Wider Distribution

Cosmopolitan.

Ecology

Usually growing in open areas, up to 2000 m alt., common throughout the region. Sometimes forms a big thicket at edge of forest or recent clearing in sunny places. This is an acidiphilous plants and common in pine forest but rather rare in limestone areas. The rhizomes run deeply underground, and can produce buds after fire. This species as a whole is distributed throughout the temperate and tropical regions and is usually known as bracken.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is the most widespread species of fern in the world and not under any known threat.

Notes

Two subspecies are in the region, Pteridium aquilinum (L.) Kuhn subsp. wightianum (J.Agardh) W.C.Shieh and Pteridium aquilinum (L.) Kuhn subsp. japonicum (Nakai) A.Löve & D.Löve.  Further work is necessary to clarify the taxonomic status of these infraspecific taxa in Asia so we are not attempting to key and describe them separately here.

The young leaves are edible, and starch is available from the rhizome .

Voucher specimens - Cambodia

Long et al. CL335, CL340 & CL426, Mondulkiri (P).