Dennstaedtiaceae is one of fifteen families in the order
Polypodiales, the most derived families within
monilophytes (ferns). It includes the world's most abundant fern,
Pteridium aquilinum (bracken). Members of the order generally have large, highly divided leaves and have either small, round intramarginal sori with cup-shaped
indusia (e.g.
Dennstaedtia) or linear marginal sori with a false indusium formed from the reflexed leaf margin (e.g.
Pteridium). The morphological diversity among members of the order has confused past taxonomy, but recent molecular studies have supported the
monophyly of the order and the family. The reclassification of Dennstaedtiaceae and the rest of the monilophytes was published in 2006, so most of the available literature is not updated.