Cystopteridaceae is a family of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

s 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 ...

. 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 relatio ...

classification of 2016 (PPG I), the family is placed in the suborder

Aspleniineae Aspleniineae is a suborder of ferns in the order Polypodiales. It is equivalent to the clade eupolypods II in earlier systems; it is also treated as a single very broadly defined family Aspleniaceae. The suborder generally corresponds with the o ...

of the order

, and includes three genera. Alternatively, it may be treated as the subfamily Cystopteridoideae of a very broadly defined family

Aspleniaceae The Aspleniaceae (spleenworts) are a family of ferns, included in the order Polypodiales. The composition and classification of the family have been subject to considerable changes. In particular, there is a narrow circumscription, Aspleniaceae ...

. Cystopteridaceae are small or medium-sized ferns in forests and crevices. They generally have thin laminae, and small, round, naked sori.

Genera

Three genera are accepted in the PPG I classification, and by the ''Checklist of Ferns and Lycophytes of the World'' . One hybrid genus also exists: *'' Acystopteris'' Nakai *''

Cystopteris ''Cystopteris'' is a genus of ferns in the family Cystopteridaceae. These are known generally as bladderferns or fragile ferns. They grow in temperate areas worldwide. This is a very diverse genus and within a species individuals can look quite ...

'' Bernh. *''

Gymnocarpium ''Gymnocarpium'' is a small genus of ferns, called oak ferns. It was once placed with various other groups, including the dryopteroid ferns and the athyrioid ferns. Cladistic analysis has demonstrated that ''Gymnocarpium'' and ''Cystopteris'' ...

'' Newman *'' ×Cystocarpium'' Fraser-Jenk. '' Cystopteris chinensis'' has been placed in a separate genus, ''Cystoathyrium'', but the genus is not accepted by recent sources.

Phylogenetic relationships

''Gymnocarpium'' and ''Cystopteris'' have been found to be sister to the remaining Aspleniineae.

References

Polypodiales Fern families {{Polypodiales-stub