Leptosporangiate ferns are the largest group of living
ferns, including some 11000 species worldwide. They constitute the subclass Polypodiidae, but are often considered to be the class
Pteridopsida or
Polypodiopsida, although other classifications assign them a different rank. The leptosporangiate ferns are one of the four major groups of ferns, with the other three being the
Eusporangiate ferns comprising the marattioid ferns (Marattiidae,
Marattiaceae), the
horsetails (Equisetiidae,
Equisetaceae), and
whisk ferns and
moonworts.