and about 6-7 other species
Brackens (Pteridium) are a genus comprising several species of large, coarse ferns. Ferns (Pteridophyta) are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells (eggs and sperm). Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly divided leaves. They are commonly found on moorland. Brackens are cosmopolitan, being found on all continents except Antarctica and in all environments except deserts. The genus probably has the widest distribution of any fern genus in the world.
In the past, the genus was commonly treated as having only one species, Pteridium aquilinum, but the recent trend is to subdivide it into about ten species.
As ferns, brackens do not have seeds or fruits, but the immature fronds, known as fiddleheads, are edible.
The word bracken is of Old Norse origin, related to the Swedish word bräken, meaning fern.
Description and biology
Evolutionarily, bracken may be considered to be one of the most successful ferns. It is also one of the oldest, with fossil records of over 55 million years old having been found. 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 ft) 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.
It is a herbaceous perennial plant, deciduous in winter. The fronds are produced singly from an underground rhizome, and grow to 1–3 m tall; the main stem is up to 1 cm diameter at the base. The rhizomes typically grow to a depth of 50 cm, although in some soils this may extend to more than a metre.
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