Bracken or Brake is a large, coarse fern, classified as Pteridium aquilinum, in the family Hypolepidaceae. It has probably the widest distribution of any fern in the world. Bracken is found on all continents except Antarctica and in all environments except for hot and cold deserts. Bracken is hardy but frost-tender, so in cold environments it is generally found growing on the sides of hills and in sheltered areas.
Bracken fiddleheads (the immature, tightly curled emerging fronds) have been considered edible by many cultures throughout history, and it is 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 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. Bracken 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 simple stomached creatures. Ruminants are less vulnerable because they synthesize thiamine.
Bracken is a prolific and abundant plant in the highlands of Great Britain. It causes such a problem of invading pastureland that the British government has an eradication program. Special filters have even been used on some British water supplies to filter out the bracken spore.
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 several feet (over a meter) underground between fronds. The fronds may grow up to eight feet (about 2.5 meters) long or longer with support, but typically are in the range of two to five feet high (about 0.5 meter to 1.5 meter).
Last of the Summer Wine, a British television sitcom, frequently featured scenes of the characters walking through bracken thickets.