Brackens (Pteridium) are a genus of about ten species of large, coarse ferns, in the family Dennstaedtiaceae. 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. Therefore it is considered to have a cosmopolitan distribution. 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 e

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # TAGS