Bracken Fern is one of 15 families in the order Polypodiales.
It comprises 10 genera with some 240 known species, including
one of the world's most abundant fern (Bracken). Members of the
order generally have large, highly divided leaves and have small,
round intramarginal sori (structures that produce spores) that
may be cup-shaped or linear. The diversity among members of the
order has confused past taxonomy, but recent studies have supported
the monophyly of the order and the family. The reclassification
of Dennstaedtiaceae was recently published in 2006, so most of
the available literature is not updated. Generally, however,
the characteristics of Bracken Fern as we know it, will have
long-creeping rhizomes that allow the plant to spread rapidly.
The leaves have stalks that are usually gutter-shaped;
smooth with a soft downy covering. The blades are large; 2 or
3 pinnate that may be divided; veins are forked, rarely vanishing.
The sori is near the leaf margin, or may be sub-marginal and
sometimes fused with the blade to form a cup or pouch.
Although the plant is known for its weedy nature, some
species are grown ornamentally.