Bracken
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Pteridium aquilinum |
Brackens (Pteridium) are a genus of about ten species of large, coarse ferns, in the family Hypolepidaceae. The genus has probably the widest distribution of any fern genus in the world, being found on all continents except Antarctica and in all environments except for hot and cold deserts. In the past, the genus was commonly treated as having only one species, Pteridium aquilinum, but the recent trend is to subdivide it into several species.
Evolutionarily, bracken may be considered to be one of the most successful ferns. The plant sends up large, triangular fronds from a wide-creeping underground rootstock, and may form dense thickets. This rootstock may travel a metre or more underground between fronds. The fronds may grow up to 2.5 m (8 feet) long or longer with support, but typically are in the range of 0.6-2 m (2-6 feet) high. In cold environments bracken is winter-deciduous, and, as it requires well-drained soil, is generally found growing on the sides of hills.
Bracken fiddleheads (the immature, tightly curled emerging fronds) have been considered edible by many cultures throughout history, and are still commonly used today as a foodstuff. Bracken fiddleheads are either consumed fresh (and cooked) or preserved by salting, pickling, or sun drying. Both fronds and rhizomes have been used to brew beer, and the rhizome starch has been used as a substitute for arrowroot. Bread can be made out of dried and powered rhizomes alone or with other flour. American Indians cooked the rhizomes, then peeled and ate them or pounded the starchy fiber into flour. In Japan, starch from the rhizomes is used to make confections.
Bracken has also been used as a form of herbal remedy. Powdered rhizome has been considered particularly effective against parasitic worms. American Indians ate raw rhizomes as a remedy for bronchitis.
Bracken has been shown to be carcinogenic and is thought to be an important cause of the high incidence of stomach cancer in Japan. It is currently under investigation as a possible source of new insecticides.
Besides causing cancer, uncooked bracken conatins the enzyme thiaminase, which breaks down thiamine. Thus, eating excessive quantities of bracken can also cause beriberi, especially in creatures with simple-stomachs. Ruminants are less vulnerable because they synthesize thiamine.
Bracken is a prolific and abundant plant in the highlands of British Isles. It causes such a problem of invading pastureland that at one time the British government had an eradication program. Special filters have even been used on some British water supplies to filter out the bracken spores.
The word bracken is of Old Norse origin, related to the Swedish word bräken, meaning fern.
Last of the Summer Wine, a British television sitcom, frequently featured scenes of the characters walking through bracken thickets.
External links
- World fern species list - Pteridium (http://homepages.caverock.net.nz/~bj/fern/pteridium.htm)
- Independent page devoted to bracken (uses older classification scheme) (http://www.rook.org/earl/bwca/nature/ferns/pteridiumaqui.html)nl:Adelaarsvaren