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 s.s., in which the family contains only two genera, and a very broad one, Aspleniaceae s.l., in which the family includes 10 other families kept separate in the narrow circumscription, with the Aspleniaceae s.s. being reduced to the subfamily Asplenioideae. The family has a worldwide distribution, with many species in both temperate and tropical areas. Elongated unpaired sori are an important characteristic of most members of the family.
Osmunda is a genus of primarily temperate-zone ferns of family Osmundaceae. Five to ten species have been listed for this genus.
Gleicheniales is an order of ferns in the subclass Polypodiidae. The Gleicheniales have records potentially as early as the Carboniferous, but the oldest unambiguous records date to the Permian.
The Dryopteridaceae are a family of leptosporangiate ferns in the order Polypodiales. They are known colloquially as the wood ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Polypodiineae. Alternatively, it may be treated as the subfamily Dryopteridoideae of a very broadly defined family Polypodiaceae sensu lato.
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.
A pteridophyte is a vascular plant that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden.
Blechnaceae is a family of ferns in the order Polypodiales, with a cosmopolitan distribution. Its status as a family and the number of genera included have both varied considerably. In the Pteridophyte Phylogeny Group classification of 2016, the family has 24 genera, and excludes genera placed in the separate family Onocleaceae. The family is divided into three subfamilies, including Blechnoideae s.s. Alternatively, the entire family may be treated as the subfamily Blechnoideae s.l. of a very broadly defined family Aspleniaceae, and include genera others place in Onocleaceae.
Pteridaceae is a family of ferns in the order Polypodiales, including some 1150 known species in ca 45 genera, divided over five subfamilies. The family includes four groups of genera that are sometimes recognized as separate families: the adiantoid, cheilanthoid, pteridoid, and hemionitidoid ferns. Relationships among these groups remain unclear, and although some recent genetic analyses of the Pteridales suggest that neither the family Pteridaceae nor the major groups within it are all monophyletic, as yet these analyses are insufficiently comprehensive and robust to provide good support for a revision of the order at the family level.
The Athyriaceae are a family of terrestrial ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Aspleniineae, and includes two genera. Alternatively, it may be treated as the subfamily Athyrioideae of a very broadly defined family Aspleniaceae. The family has with a cosmopolitan distribution.
Athyrium (lady-fern) is a genus of about 180 species of terrestrial ferns, with a cosmopolitan distribution. It is placed in the family Athyriaceae, in the order Polypodiales. Its genus name is from Greek a- ('without') and Latinized Greek thyreos ('shield'), describing its inconspicuous indusium . The common name "lady fern" refers in particular to the common lady fern, Athyrium filix-femina.
Onocleaceae is a small family of terrestrial ferns in the order Polypodiales. It is placed in the suborder Aspleniineae in the Pteridophyte Phylogeny Group classification of 2016. Alternatively, the family, along with Blechnaceae, may be placed in a very broadly defined family Aspleniaceae as the subfamily Blechnoideae. The family may contain from one to four genera, consisting of five species largely in north temperate climes. The four genera, Matteuccia, Onoclea, Onocleopsis and Pentarhizidium, may be included under the single genus Onoclea.
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 order Blechnales as described by J. L. Reveal in 1993. Aspleniineae includes some important ferns, including Onoclea sensibilis, the sensitive fern, which grows as a virtual weed throughout much of its temperate North American range, and ferns of the genus Thelypteris, a genus that has shown remarkable speciation. It also includes one of the more common horticultural ferns, Matteuccia struthiopteris, the ostrich fern.
Saccolomataceae is a family of ferns in the order Polypodiales with about 19 species. It has been formerly treated as part of the Dennstaedtiaceae, however it has been classified as its own family according to Smith et al. (2006) The genus Saccoloma has been classified to include Orthiopteris, but the phylogeny of the group not yet fully understood. The family includes a dozen known species.
Diplazium is a genus of ferns that specifically includes the approximately 400 known species of twinsorus ferns. The Greek root is diplazein meaning double: the indusia in this genus lie on both sides of the vein. These ferns were earlier considered part of either the Athyriaceae, Dryopteridaceae, Aspleniaceae, or Polypodiaceae families or recognized as belonging to their own taxonomic family. The Pteridophyte Phylogeny Group classification of 2016 places the genus in the Athyriaceae. The taxonomy of the genus is difficult and poorly known, and by 2009 has never been the subject of a complete monographic study. Their distribution is pantropical, with a few species extending into temperate areas.
Polypodiineae is a suborder of ferns in the order Polypodiales. It is equivalent to the clade eupolypods I in earlier systems, and to the very broadly defined family Polypodiaceae in the classification of Christenhusz & Chase (2014). It probably diverged from the suborder Aspleniineae during the mid-Cretaceous. The divergence is supported by both molecular data and an often overlooked morphological characteristic which lies in the vasculature of the petiole. Most species that make up the suborder have three vascular bundles. The only exceptions are the grammitid ferns which have one, and the genus Hypodematium which has two. This differs from eupolypods II which mostly have two vascular bundles.
Rhachidosorus is a genus of ferns in the order Polypodiales. It is the only genus in the family Rhachidosoraceae in the Pteridophyte Phylogeny Group classification of 2016. Alternatively, the genus may be placed in the subfamily Rhachidosoroideae of a more broadly defined family Aspleniaceae, the family placement used in Plants of the World Online as of November 2019.
Vittarioideae is a subfamily of the fern family Pteridaceae, in the order Polypodiales. The subfamily includes the previous families Adiantaceae and Vittariaceae.
Cryptogrammoideae is a subfamily of ferns in the family Pteridaceae. The subfamily contains three genera and about 23 species.
Hymenasplenium is one of three genera of ferns in the Aspleniaceae, in the eupolypods II clade of the order Polypodiales. The others are Hemidictyum and Asplenium. Hymenasplenium was segregated because it is a natural grouping with differing rhizome morphology – dorsiventral v. radial for the rest of Asplenium, differing chromosome count – x=39 v. x=36 for the rest of Asplenium, and a clear monophyletic grouping based on genetic analysis. It was confirmed as a sister group to Asplenium in a 2015 molecular study of the genera.
Ophioglossidae is one of the four subclasses of Polypodiopsida (ferns). This subclass consists of the ferns commonly known as whisk ferns, grape ferns, adder's-tongues and moonworts. It is equivalent to the class Psilotopsida in previous treatments, including Smith et al. (2006). The subclass contains two orders, Psilotales and Ophioglossales, whose relationship was only confirmed by molecular phylogenetic studies.
