Ceratopteridaceae is an improper family name for the clade that is now known to include the two genera ''

Ceratopteris ''Ceratopteris'' is the only genus among homosporous ferns that is exclusively aquatic. It is pan-tropical and classified in the Parkerioideae subfamily of the family Pteridaceae. Description Erect aquatic or subaquatic ferns of moderate size. ...

'' and ''

Acrostichum ''Acrostichum'' is a fern genus in the Parkerioideae subfamily of the Pteridaceae. It was one of the original pteridophyte genera delineated by Linnaeus. It was originally drawn very broadly, including all ferns that had sori apparently "ac ...

''. Although ''Ceratopteris'' was long isolated under its own family, due to adaptations for a dedicated aquatic existence, recent genetic study has determined that these two genera are allied. The correct name for this taxon at the level of family is Parkeriaceae; in the

Pteridophyte Phylogeny Group The Pteridophyte Phylogeny Group, or PPG, is an informal international group of systematic botanists who collaborate to establish a consensus on the classification of pteridophytes (lycophytes and ferns) that reflects knowledge about plant relation ...

classification of 2016 (PPG I), it is treated as the subfamily

Parkerioideae Parkerioideae, Synonym (taxonomy), synonym Ceratopteridoideae, is one of the five subfamilies in the fern family Pteridaceae. It includes only the two genera ''Acrostichum'' and ''Ceratopteris''. The following diagram shows a likely phylogenic re ...

. Christenhusz ''et al.'', 2011, included these two genera alone in the subfamily Ceratopteridoideae (now the Parkerioideae) in their larger treatment of the family

Pteridaceae Pteridaceae is a family of ferns in the order Polypodiales, including some 1150 known species in ca 45 genera (depending on taxonomic opinions), divided over five subfamilies. The family includes four groups of genera that are sometimes recogni ...

in the order

Polypodiales The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas. Description Polypodiale ...

References

{{Taxonbar, from=Q5063806 Pteridaceae Fern families Historically recognized plant families