Below are lists of extant

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 ...

families and subfamilies using the classification scheme proposed by 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 ...

in 2016 (PPG I). The scheme is based on molecular phylogenetic studies, and also draws on earlier classifications, particularly those by Smith ''et al.'' (2006), Chase and Reveal (2009), and Christenhusz ''et al.'' (2011). It rejects the very broad

circumscription Circumscription may refer to: *Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) *Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthrop ...

of some families used by Christenhusz and Chase (2014), whose Aspleniaceae corresponds to the entire 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 PPG I. __TOC__

Systematic order

*Class

Polypodiopsida 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 ...

Cronquist, Takht. & W.Zimm. (ferns, including horsetails) :*Subclass

Equisetidae Equisetidae is one of the four subclasses of Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with whorls of needle-lik ...

Warm. (horsetails and scouring-rushes) ::*Order

Equisetales Equisetales is an order of subclass Equisetidae with only one living family, Equisetaceae Equisetaceae, sometimes called the horsetail family, is the only extant family of the order Equisetales, with one surviving genus, ''Equisetum'', which ...

DC. ex Bercht. & J.Presl ::::*Family

Equisetaceae Equisetaceae, sometimes called the horsetail family, is the only extant family of the order Equisetales, with one surviving genus, ''Equisetum'', which comprises about twenty species. Evolution and systematics Equisetaceae is the only survivin ...

Michx. ex DC :*Subclass

Ophioglossidae 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 treatm ...

Klinge (whisk ferns, adder's-tongues and moonworts) ::*Order

Psilotales Psilotaceae is a family of ferns (class Polypodiopsida) consisting of two genera, '' Psilotum'' and ''Tmesipteris'' with about a dozen species. It is the only family in the order Psilotales. Description Once thought to be descendants of early va ...

Prant ::::*Family

Psilotaceae Psilotaceae is a family of ferns (class Polypodiopsida) consisting of two genera, ''Psilotum'' and '' Tmesipteris'' with about a dozen species. It is the only family in the order Psilotales. Description Once thought to be descendants of early v ...

J.W.Griff. & Henfr. ::*Order

Ophioglossales Ophioglossaceae, the adder's-tongue family, is a small family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is the only family in the order Ophioglossales, which together with the Psilotales is placed in the su ...

Link ::::*Family Ophioglossaceae Martinov :::::*Subfamily Helminthostachyoideae C.Presl :::::*Subfamily Mankyuoideae J.R.Grant & B.Dauphin :::::*Subfamily Ophioglossoideae C.Presl :::::*Subfamily Botrychioideae C.Presl :*Subclass

Marattiidae Marattiaceae is the only family of extant (living) ferns in the order Marattiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), Marattiales is the only order in the subclass Marattiidae. The family has six genera and about ...

Klinge (marattioid ferns) ::*Order

Marattiales Marattiaceae is the only family of extant (living) ferns in the order Marattiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), Marattiales is the only order in the subclass Marattiidae. The family has six genera and about ...

Link ::::*Family

Marattiaceae Marattiaceae is the only family of extant (living) ferns in the order Marattiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), Marattiales is the only order in the subclass Marattiidae. The family has six genera and about ...

Kaulf :*Subclass

Polypodiidae Polypodiidae may refer to: * Polypodiidae (cnidarians), a zoological family that only includes ''Polypodium hydriforme'', a cnidarian parasite of fish eggs *Polypodiidae (plant), a botanical subclass of Equisetopsida sensu lato that includes the le ...

Cronquist, Takht. & W.Zimm. (leptosporangiate ferns) ::*Order

Osmundales Osmundaceae (royal fern family) is a family of ferns containing four to six extant genera and 18–25 known species. It is the only living family of the order Osmundales in the class Polypodiopsida (ferns) or in some classifications the only ord ...

Link (royal ferns) ::::*Family

Osmundaceae Osmundaceae (royal fern family) is a family of ferns containing four to six extant genera and 18–25 known species. It is the only living family of the order Osmundales in the class Polypodiopsida (ferns) or in some classifications the only ord ...

Martinov ::*Order

Hymenophyllales The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp pla ...

A.B.Frank (filmy ferns and bristle ferns) ::::*Family

Hymenophyllaceae The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp pla ...

Mart :::::*Subfamily

Trichomanoideae The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp pla ...

C.Presl :::::*Subfamily Hymenophylloideae Burnett ::*Order

Gleicheniales :''This article defines the Gleicheniales in a loose sense. For the restricted definition, see Gleicheniaceae.'' Gleicheniales is an order of ferns in the subclass Polypodiidae (the leptosporangiate ferns). The Gleicheniales have records potenti ...

Schimp ::::*Family

Matoniaceae Matoniaceae is one of the three families of ferns in the Gleicheniales order of the Polypodiopsida class. Fossil records reveal that Matoniaceae ferns were abundant during the Mesozoic era (about 250-million to 66-million years ago), during which ...

C.Pres ::::*Family

Dipteridaceae The Dipteridaceae is a family of ferns in the order Gleicheniales of the class Polypodiopsida. They are commonly known as umbrella ferns and contain two genera, ''Cheiropleuria'' and ''Dipteris'', with a total of nine species confined to Asia, N ...

Seward & E.Dale ::::*Family

Gleicheniaceae The forked ferns are the family Gleicheniaceae, which includes six genera and about 160 known species. The formerly independent families Dicranopteridaceae and Stromatopteridaceae are generally included in the Gleicheniaceae, whereas the Dipteri ...

C.Presl ::*Order

Schizaeales Schizaeales is an order of ferns (class Polypodiopsida). Description While the three clades of Schizaeales are all well-distinguished from one another by numerous morphological characters, members of the order all have dimorphic fertile and s ...

Schimp. ::::*Family Lygodiaceae M.Roem ::::*Family Schizaeaceae Kaulf ::::*Family Anemiaceae Link ::*Order

Salviniales The order Salviniales (formerly known as the Hydropteridales and including the former Marsileales) is an order of ferns in the class Polypodiopsida. Description Salviniales are all aquatic and differ from all other ferns in being heterosporous, ...

Link ::::*Family

Salviniaceae Salviniaceae (), is a family of heterosporous ferns in the order Salviniales. The Salviniaceae contain the two genera ''Azolla'' and ''Salvinia ''Salvinia'', a genus in the family Salviniaceae, is a floating fern named in honor of Anton Ma ...

Martinov ::::*Family

Marsileaceae Marsileaceae () is a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group is commonly known as the "pepperwort family" or as the "water-clover family" because ...

Mirb. ::*Order Cyatheales A.B.Frank (tree ferns) ::::*Family

Thyrsopteridaceae ''Thyrsopteris'' is a genus of tree fern. It contains a single living species, ''Thyrsopteris elegans'', endemic to the Juan Fernandez Archipelago off the coast of Chile. ''Thyrsopteris'' is the only genus in the family Thyrsopteridaceae in the ...

C.Presl ::::*Family

Loxsomataceae The Loxsomataceae are a family of ferns in the order Cyatheales with two extant genera in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may be treated as the subfamily Loxsomatoideae of a very broadly ...

C.Presl ::::*Family

Culcitaceae ''Culcita'' is a genus of ferns, native to the Americas, Macaronesia and Iberian Peninsula. It is the only genus in the family Culcitaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may be treated ...

Pic.Serm ::::*Family

Plagiogyriaceae ''Plagiogyria'' is a genus of ferns, the only genus in family Plagiogyriaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may be treated as the subfamily Plagiogyrioideae of a very broadly defined ...

Bowe ::::*Family

Cibotiaceae ''Cibotium'' (from Ancient Greek language, Greek , ''kibṓtion'', "little chest" or "box"), also known as manfern, is a genus of 11 species of tropical Cyatheales, tree ferns. It is the only genus in family Cibotiaceae in the Pteridophyte Phylog ...

Koral ::::*Family

Metaxyaceae ''Metaxya'' is a neotropical genus of ferns in the order Cyatheales. It is the only genus in the family Metaxyaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the genus may be placed in the subfamily Metax ...

Pic.Serm. ::::*Family

Dicksoniaceae Dicksoniaceae is a group of tropical, subtropical and warm temperate ferns, treated as a family in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), and counting 30-40 species. Alternatively, the family may be sunk into a very bro ...

M.R.Schomb. ::::*Family

Cyatheaceae The Cyatheaceae are a family of ferns, the scaly tree ferns, one of eight families in the order Cyatheales in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may defined much more broadly (Cyatheaceae ...

Kaulf. ::*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 ...

Link :::*Suborder Saccolomatineae Hovenkamp ::::*Family

Saccolomataceae 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 '' Sa ...

Doweld :::*Suborder Lindsaeineae Lehtonen & Tuomist ::::*Family

Cystodiaceae ''Cystodium'' is a fern in its own family, Cystodiaceae. It contains a single species: ''Cystodium sorbifolium'' . Because it looks like a small tree fern, it had previously been placed in the tree fern family Dicksoniaceae. Subsequent analysis ...

J.R.Croft ::::*Family Lonchitidaceae Doweld ::::*Family Lindsaeaceae C.Presl ex M.R.Schomb. :::*Suborder Pteridineae J.Prado & Schuettp ::::*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 ...

E.D.M.Kirchn. :::::*Subfamily Parkerioideae Burnett :::::*Subfamily Cryptogrammoideae S.Lindsay :::::*Subfamily Pteridoideae Link :::::*Subfamily

Vittarioideae Vittarioideae is a subfamily of the fern family Pteridaceae, in the order Polypodiales. The subfamily includes the previous families Adiantaceae (adiantoids or maidenhair ferns) and Vittariaceae (vittarioids or shoestring ferns). Description The ...

Link :::::*Subfamily Cheilanthoideae Horvat :::*Suborder Dennstaedtiineae Schwartsb. & Hovenkamp ::::*Family

Dennstaedtiaceae Dennstaedtiaceae is one of fifteen families in the order Polypodiales, the most derived families within monilophytes (ferns). It comprises 10 genera with ca 240 known species, including one of the world's most abundant ferns, ''Pteridium aquilin ...

Lotsy :::*Suborder

H.Schneid. & C.J.Rothf ::::*Family Cystopteridaceae Shmakov ::::*Family Rhachidosoraceae X.C.Zhang ::::*Family Diplaziopsidaceae X.C.Zhang & Christenh. ::::*Family Desmophlebiaceae Mynssen ::::*Family

Hemidictyaceae ''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 (PPG I), it is the only genus in the family Hemidic ...

Christenh. & H.Schneid. ::::*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 ...

Newman ::::*Family

Woodsiaceae ''Woodsia'' is a genus of ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is the only genus in the family Woodsiaceae, placed in the suborder Aspleniineae. The family can also be trea ...

Herter ::::*Family

Onocleaceae 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 (PPG I). Alternatively, the family, along with Blechnaceae, may be ...

Pic.Serm. ::::*Family

Blechnaceae 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 ...

Newman :::::*Subfamily Stenochlaenoideae (Ching) J.P.Roux :::::*Subfamily Woodwardioideae Gasper :::::*Subfamily

Blechnoideae 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 ...

Gasper, V.A.O.Dittrich & Salino ::::*Family

Athyriaceae The Athyriaceae (ladyferns and allies) 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 gene ...

Alston ::::*Family

Thelypteridaceae Thelypteridaceae is a family of about 900 species of ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is placed in the suborder Aspleniineae. Alternatively, the family may be submerged in a ...

Ching ex Pic.Serm. :::::*Subfamily Phegopteridoideae Salino, A.R.Sm. & T.E.Almeid :::::*Subfamily Thelypteridoideae C.F.Reed :::*Suborder

Polypodiineae 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 ...

Dumort. ::::*Family Didymochlaenaceae Ching ex Li Bing Zhang & Liang Zhang ::::*Family Hypodematiaceae Ching ::::*Family

Dryopteridaceae 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 ...

Herter :::::*Subfamily

Polybotryoideae Polybotryoideae is a subfamily of the fern family Dryopteridaceae. Genera The Pteridophyte Phylogeny Group classification of 2016 (PPG I) accepts the following genera: * '' Cyclodium'' C.Presl * ''Maxonia ''Maxonia'' is a genus of ferns in ...

H.M.Liu & X.C.Zhang :::::*Subfamily

Elaphoglossoideae Elaphoglossoideae is a subfamily of the fern family Dryopteridaceae 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 clas ...

(Pic.Serm.) Crabbe, Jermy & Mickel :::::*Subfamily Dryopteridoideae Link :::::*2 genera unassigned to a subfamily ::::*Family Nephrolepidaceae Pic.Serm. ::::*Family Lomariopsidaceae Alston ::::*Family

Tectariaceae Tectariaceae is a family of leptosporangiate ferns in the order Polypodiales. 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 ...

Panigrahi ::::*Family Oleandraceae Ching ex Pic.Serm. ::::*Family Davalliaceae M.R.Schomb. ::::*Family

Polypodiaceae Polypodiaceae is a family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family includes around 65 genera and an estimated 1,650 species and is placed in the order Polypodiales, suborder Polypodiineae. A broade ...

J.Presl & C.Presl :::::*Subfamily

Loxogrammoideae Loxogrammoideae is a small subfamily of the fern family Polypodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), with two genera, '' Dictymia'' and '' Loxogramme''. The subfamily was previously considered to be a se ...

H.Schneid. :::::*Subfamily

Platycerioideae Platycerioideae is a small subfamily of the fern family Polypodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The subfamily is also treated as the tribe Platycerieae within a very broadly defined family Polypodi ...

B.K.Nayar :::::*Subfamily

Drynarioideae Drynarioideae is a subfamily of the fern family Polypodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The subfamily is also treated as the tribe Drynarieae within a very broadly defined family Polypodiaceae ''sen ...

Crabbe, Jermy & Mickel :::::*Subfamily Microsoroideae B.K.Nayar :::::*Subfamily

Polypodioideae Polypodioideae is a subfamily belonging to the fern family Polypodiaceae, which is a member of the suborder Polypodiineae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the subfamily may be treated as th ...

Sweet :::::*Subfamily

Grammitidoideae 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 w ...

Parris & Sundue :::::*1 genus unassigned to a subfamily

Alphabetic order

* Anemiaceae Link (1 genus) *

Newman (2 genera) *

Alston (3 genera) *

Newman (24 genera) *

Koral (1 genus) *

Pic.Serm (1 genus) *

Kaulf. (3 genera) *

J.R.Croft (1 genus) * Cystopteridaceae Shmakov (3 genera) * Davalliaceae M.R.Schomb. (1 genus) *

Lotsy (10 genera) * Desmophlebiaceae Mynssen (1 genus) *

M.R.Schomb. (3 genera) * Didymochlaenaceae Ching ex Li Bing Zhang & Liang Zhang (1 genus) * Diplaziopsidaceae X.C.Zhang & Christenh. (2 genera) *

Seward & E.Dale (2 genera) *

Herter (26 genera) *

Michx. ex DC (1 genus) *

C.Presl (6 genera) *

Christenh. & H.Schneid. (1 genus) *

Mart (9 genera) * Hypodematiaceae Ching (2 genera) * Lindsaeaceae C.Presl ex M.R.Schomb. (7 genera) * Lomariopsidaceae Alston (4 genera) * Lonchitidaceae Doweld (1 genus) *

C.Presl (2 genera) * Lygodiaceae M.Roem (1 genus) *

Kaulf (6 genera) *

Mirb. (3 genera) *

C.Pres (2 genera) *

Pic.Serm. (1 genus) * Nephrolepidaceae Pic.Serm. (1 genus) * Oleandraceae Ching ex Pic.Serm. (1 genus) *

Pic.Serm. (4 genera) * Ophioglossaceae Martinov (10 genera) *

Martinov (6 genera) *

Bowe (1 genus) *

J.Presl & C.Presl (65 genera) *

J.W.Griff. & Henfr. (2 genera) *

E.D.M.Kirchn. (53 genera) * Rhachidosoraceae X.C.Zhang (1 genus) *

Doweld (1 genus) *

Martinov (2 genera) * Schizaeaceae Kaulf (2 genera) *

Panigrahi (7 genera) *

Ching ex Pic.Serm. (30 genera) *

C.Presl (1 genus) *

Herter (1 genus)

References

{{reflist, refs= {{cite journal , author=PPG I , year=2016 , title=A community-derived classification for extant lycophytes and ferns , journal=Journal of Systematics and Evolution , volume=54 , issue=6 , pages=563–603 , doi=10.1111/jse.12229 {{cite journal , author1=Alan R. Smith , author2=Kathleen M. Pryer , author3=Eric Schuettpelz , author4=Petra Korall , author5=Harald Schneider , author6=Paul G. Wolf , year=2006 , title=A classification for extant ferns , journal=Taxon , volume=55 , issue=3 , pages=705–731 , doi=10.2307/25065646 , url=http://www.pryerlab.net/publication/fichier749.pdf , url-status=dead , archiveurl=https://web.archive.org/web/20080226232147/http://www.pryerlab.net/publication/fichier749.pdf , archivedate=2008-02-26 {{cite journal , author=Maarten J. M. Christenhusz, Xian-Chun Zhang & Harald Schneider , year=2011 , title=A linear sequence of extant families and genera of lycophytes and ferns , journal=

Phytotaxa ''Phytotaxa'' is a peer-reviewed scientific journal for rapid publication on any aspect of systematic botany. It publishes on a wide range of subjects, but focuses on new species, monographs, floras, revisions, reviews, and typification issues ...

, volume=19, pages=7–54 , url=http://www.mapress.com/phytotaxa/content/2011/f/pt00019p054.pdf {{Cite journal, last1= Christenhusz , first1=Maarten J.M., authorlink1=Maarten J. M. Christenhusz , last2=Chase, first2=Mark W., authorlink2=Mark W. Chase , year=2014 , title=Trends and concepts in fern classification , journal=

Annals of Botany ''Annals of Botany'' is a monthly peer-reviewed scientific journal publishing experimental, theoretical and applied papers on all aspects of plant biology. The current (2022) Chief Editor is Rowan Sage, replacing John Seymour (Pat) Heslop-Harriso ...

, volume=113 , issue=9 , pages=571–594 , name-list-style=amp , doi=10.1093/aob/mct299 , pmid=24532607 , pmc=3936591 {{cite journal , author1=Mark W. Chase , author2=James L. Reveal , name-list-style=amp, year=2009 , title=A phylogenetic classification of the land plants to accompany APG III , journal=

Botanical Journal of the Linnean Society The ''Botanical Journal of the Linnean Society'' is a scientific journal publishing original papers relating to the taxonomy of all plant groups and fungi, including anatomy, biosystematics, cytology, ecology, ethnobotany, electron microscopy, ...

, volume=161, pages=122–127 , url=https://www.scribd.com/doc/51117527/CHASE-REVEAL-2009-A-phylogenetic-classi%EF%AC%81cation-of-the-land-plants-to-accompany-APG-III , doi=10.1111/j.1095-8339.2009.01002.x, doi-access=free 01 . * Fern families