All ferns except the Royal Ferns (Osmundaceae), Ferns (Hymenophyllaceae), Adder's-Tongue Ferns (Ophioglossaceae), Water Ferns (Azollaceae), Water Clovers (Marsileaceae), and Floating Ferns (Salviniaceae) are here summed up as Real Ferns (Pteridopsida). In between this inhomogeneous group has been splitted into many smaller families:
- Genus Pteridium forms family Dennstaedtiaceae.
- Genus Adiantum, Anogramma, Cheilanthes, Cryptogramma, and Pteris are in between maintained under the family Pteridaceae.
- Genus Asplenium forms family Aspleniaceae.
- Genus Thelypteris, Oreopteris, and Phegopteris are assigned to the family Thelypteridaceae.
- Genus Blechnum forms family Blechnaceae.
- Genus Athyrium, Cystopteris, Gymnocarpium, and Woodsia are now maintained under the family Woodsiaceae.
- Genus Matteuccia and Onoclea are assigned to the family Onocleaceae.
- Genus Dryopteris, Cyrtomium, and Polystichum are now maintained under family Dryopteridaceae.
- Genus Polypodium forms family Polypodiaceae.
- Genus Davallia (Hare's-Foot Fern) forms family Davalliaceae.