Thelypteridaceae is a family of about 900 species of ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the suborder Aspleniineae. Alternatively, the family may be submerged in a very broadly defined family Aspleniaceae as the subfamily Thelypteridoideae.
Ophioglossaceae, the adder's-tongue family, is a small family of ferns. In the Pteridophyte Phylogeny Group classification of 2016, it is the only family in the order Ophioglossales, which together with the Psilotales is placed in the subclass Ophioglossidae. The Ophioglossidae are one of the groups traditionally known as eusporangiate ferns. Members of the family differ from other ferns in a number of ways. Many have only a single fleshy leaf at a time. Their gametophytes are subterranean and rely on fungi for energy.
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.
Polypodiaceae is a family of ferns. In the Pteridophyte Phylogeny Group classification of 2016, the family includes around 65 genera and an estimated 1,650 species and is placed in the order Polypodiales, suborder Polypodiineae. A broader circumscription has also been used, in which the family includes other families kept separate in PPG I. Nearly all species are epiphytes, but some are terrestrial.
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 Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp places or to locations where they are wetted by spray from waterfalls or springs. A recent fossil find shows that ferns of Hymenophyllaceae have existed since at least the Upper Triassic.
Lorinseria is a genus of fern in the subfamily Woodwardioideae of the family Blechnaceae. Its only species is Lorinseria areolata, the netted chain fern, native to eastern North America. The monotypic genus Lorinseria has been separated from Woodwardia in the Pteridophyte Phylogeny Group classification of 2016, on the basis of its anastamosing veins and lobed frond form, as well as its more marked frond dimorphism. However, the genus name Lorinseria appears to be a later homonym of LorinseraOpiz, and will need to be replaced or conserved.
Blechnum, known as hard fern, is a genus of ferns in the family Blechnaceae, subfamily Blechnoideae, according to the Pteridophyte Phylogeny Group classification of 2016. Two very different circumscriptions of the genus are used by different authors. In the PPG I system, based on Gasper et al. (2016), Blechnum is one of 18 genera in the subfamily Blechnoideae, and has about 30 species. Other sources use a very broadly defined Blechnum s.l., including accepting only two other genera in the subfamily. The genus then has about 250 species. In the PPG I circumscription, the genus is mostly neotropical, with a few southern African species.
Aleuritopteris is a genus of ferns in the Cheilanthoideae subfamily of the Pteridaceae. As with some other genera of the Cheilanthoideae, molecular phylogenetic studies have suggested that it is not monophyletic, and so may need to be circumscribed differently in future.
Thelypteris is a genus of ferns in the subfamily Thelypteridoideae, family Thelypteridaceae, order Polypodiales. Two radically different circumscriptions of the genus are in use as of January 2020. In the Pteridophyte Phylogeny Group classification of 2016, the genus is a very small one with about two species. In other approaches, the genus is the only one in the subfamily Thelypteridoideae, and so includes between 875 and 1083 species.
Grammitidoideae is a subfamily of the fern family Polypodiaceae, whose members are informally known as grammitids. It comprises a clade of about 750 species. They are distributed over higher elevations in both the Old and New World. This group was previously treated as a separate family, Grammitidaceae until molecular phylogenies showed it to be nested within the Polypodiaceae. It has since been treated as an unranked clade within subfamily Polypodioideae, and, most recently, as a separate subfamily.
Hemidictyum is a genus of ferns with a single species, Hemidictyum marginatum, commonly known as the marginated half net fern. In the Pteridophyte Phylogeny Group classification of 2016, it is the only genus in the family Hemidictyaceae. Alternatively, the family, along with Aspleniaceae sensu stricto, may be placed in a much more broadly defined family Aspleniaceae as the subfamily Asplenioideae.
Didymoglossum is a tropical genus of ferns in the family Hymenophyllaceae. It comprises more than 30 epilithic or low-epiphytic species under two subgenera. The genus is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not by some other sources which sink it into a broadly defined Trichomanes.
Vittarioideae is a subfamily of the fern family Pteridaceae, in the order Polypodiales. The subfamily includes the previous families Adiantaceae and Vittariaceae.
Cheilanthoideae is one of the five subfamilies of the fern family Pteridaceae. The subfamily is thought to be monophyletic, but some of the genera into which it has been divided are not, and the taxonomic status of many of its genera and species remains uncertain, with radically different approaches in use as of December 2019.
Anchistea is a genus of leptosporangiate ferns in the family Blechnaceae. It has only one species, Anchistea virginica the Virginia chain fern, which has long creeping, scaly, underground stems or rhizomes giving rise to tall widely separated, deciduous, single leaves. In contrast, the leaves of Osmundastrum cinnamomeum, which can be mistaken for A. virginica, grow in a group from a crown. Also in contrast to O. cinnamomeum the leaves are monomorphic without distinct fertile fronds. The lower petiole or stipe is dark purple to black, shiny and swollen, the upper rachis is dull green. The leaf blade is green and lanceolate, composed of 12 to 23 paired, alternate pinnatifid pinnae. The pinnae are subdivided into 15 to 20 paired segments that are ovate to oblong. The lower rachis is naked for about half its length. The sori or spore-producing bodies are found on the underside of the pinnae and are long and form a double row which outlines the major veins of the pinnae. In common with all ferns, A. virginica exhibits a gametophyte stage in its life cycle and develops a haploid reproductive prothallus as an independent plant. The spores are produced in red-brown sori which line the spaces (areolae) between the costa and costules. Further photographs can be found at the Connecticut Botanical Society and Ontario Ferns websites.
Blechnopsis is a small genus of ferns in the family Blechnaceae, subfamily Blechnoideae, according to the Pteridophyte Phylogeny Group classification of 2016. The genus is accepted in a 2016 classification of the family Blechnaceae, but other sources sink it into a very broadly defined Blechnum, equivalent to the whole of the PPG I subfamily.
Hemionitis is a genus of ferns in the subfamily Cheilanthoideae of the family Pteridaceae. Its circumscription varies greatly in different systems of fern classification. In the Pteridophyte Phylogeny Group classification of 2016, it was one of more than 20 genera in the subfamily Cheilanthoideae, and was said to have five species. Other sources treat it as the only genus in the subfamily, and so accept about 450 species. With the restricted circumscription, species are native to tropical America.
Lemmaphyllum is a genus of ferns in the family Polypodiaceae, subfamily Microsoroideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I).
