{{Short description|Order of ferns}} {{Automatic taxobox | name = Tree fern (Cyatheales) | fossil_range = {{fossil range|Early Jurassic|Recent}}<ref>{{Cite journal |date=1978 |title=Regional stratigraphic table of northern China, Nei Monggol |journal=Geological Publishing House}}</ref> | image = Dicksonia antarctica in Nunniong, Australia.jpg | image_caption = ''Dicksonia antarctica'' | taxon = Cyatheales | authority = A.B.Frank | subdivision_ranks = Families | subdivision = * Thyrsopteridaceae * Loxsomataceae * Culcitaceae * Plagiogyriaceae * Cibotiaceae * Metaxyaceae * Dicksoniaceae * Cyatheaceae * ?{{extinct}}Tempskyaceae Note: These families are alternatively treated as subfamilies of the single family Cyatheaceae <ref name="christenhusz-chase-2014">{{Cite journal |last=Christenhusz |first=Maarten J. M. |last2=Chase |first2=Mark W. |date=13 February 2014 |title=Trends and concepts in fern classification |journal=Annals of Botany |volume=113 |issue=4 |pages=571–594 |doi=10.1093/aob/mct299 |pmc=3936591 |pmid=24532607}}</ref> }}
The order '''Cyatheales''', which includes most tree ferns, is a taxonomic order of the fern class, Polypodiopsida.<ref name=Koral-2007/> No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicate the order is monophyletic. Some species in the Cyatheales have tree-like growth forms from a vertical rhizome, others have shorter or horizontal expanding rhizomes.
Some species have scales on the stems and leaves, while others have hairs. However, most plants in the Cyatheales are tree ferns and have trunk-like stems up to {{convert|10|m|ft}} tall. It is unclear how many times the tree form has evolved and been lost in the order.<ref name="Judd 2008">Judd, W.S., C.S. Campbell, E.A. Kellogg, P.F. Stevens, and M.J. Donoghue (Eds.) 2008. Plant Systematics: A Phylogenetic Approach, Third Edition. Sinauer Associates, Sunderland, Massachusetts, USA.</ref>
==Description== While the Cyatheales have been shown to be monophyletic through molecular analysis, no prominent morphological characteristics are common to the entire group.<ref>{{Cite book |last=Schuettpelz |first=Eric |url=https://archive.org/details/biologyevolution00rank_362 |title=Biology and Evolution of Ferns and Lycophytes |last2=Pryer |first2=Kathleen M. |publisher=Cambridge University Press |year=2008 |isbn=978-0-521-69689-0 |editor-last=Ranker |editor-first=Tom A. |location=Cambridge |page=[https://archive.org/details/biologyevolution00rank_362/page/n425 404] |chapter=Fern Phylogeny |editor-last2=Haufler |editor-first2=Christopher H. |url-access=registration}}</ref> Though loosely referred to as "tree ferns", most but not all members of the order possess the characteristic tree fern morphology: the rhizome is massive, woody, and rather than creeping horizontally below or on the ground, it stands erect and above ground, like a tree trunk, bearing a crown of fronds. This habit is most evident in families Dicksoniaceae and Cyatheaceae. Outside of the Cyatheales, a few ferns in other groups could be considered tree ferns, such as several ferns (''Leptopteris'' and ''Todea'') in the family Osmundaceae that can achieve short trunks under {{convert|1|m|ft}} tall. A few species in the genera ''Blechnum and Sadleria'' could also be considered tree ferns in a liberal interpretation of the term. {{cn|date=June 2025}}
Like all ferns, tree ferns reproduce by means of spores developed in sporangia on the undersides of the fronds.{{cn|date=June 2025}}
thumb|left|''Dicksonia antarctica'' at Kew
The fronds of tree ferns are usually very large and multiple-pinnated, but at least one type has entire (undivided) fronds. The fronds of tree ferns also exhibit circinate vernation, meaning the young fronds emerge in coils that uncurl as they grow.{{cn|date=June 2025}}
Unlike flowering plants, tree ferns do not form new woody tissue in their trunk as they grow. Rather, the trunk is supported by a fibrous mass of roots that expands as the tree fern grows.{{clarify|reason=huh? does the trunk never grow bigger then, or what?|date=December 2024}}
Some genera — for example ''Dicksonia'' and ''Cibotium'', and some ''Cyathea'' — can be transplanted by severing the top portion from the rest of the trunk and replanting it. If the transplanted top part is kept moist it will regrow a new root system over the next year. The success rate of transplantation increases if the roots are dug up intact. If the crown of the Tasmanian tree fern ''Dicksonia antarctica'' (the most common species in gardens) is damaged, it will die because all new growth occurs there. But other clump-forming tree fern species, such as ''D. squarrosa'' and ''D. youngiae'', can regenerate from basal offsets or from "pups" emerging along the surviving trunk length. Tree ferns often fall over in the wild, yet manage to reroot from this new prostrate position and begin new vertical growth.{{cn|date=June 2025}} [[Image:Tree fern frond at Akatarawa.jpg|thumb|left|Tree fern frond ("fiddlehead") by the Akatarawa River, New Zealand.]] The number of tree fern species is likely to be around a thousand. Although new species are discovered in New Guinea with each botanical survey, many species throughout its range have become extinct in the last century as forest habitats have come under pressure from human activities.{{cn|date=June 2025}}
[[Image:nzfern.arp.500pix.jpg|thumb|right|Transplanted ''Dicksonia antarctica'' tree ferns at Combe Martin Wildlife and Dinosaur Park, Devon, England]]
==Taxonomy== In the molecular phylogenetic classification of Smith et al. in 2006, the Cyatheales were placed in the leptosporangiate ferns, class Polypodiopsida. Eight families, Thyrsopteridaceae, Loxsomataceae, Culcitaceae, Plagiogyriaceae, Cibotiaceae, Cyatheaceae, Dicksoniaceae, and Metaxyaceae, were recognized.<ref name="smith-etal-2006">{{Cite journal |last=Smith |first=Alan R. |last2=Pryer |first2=Kathleen M. |last3=Schuettpelz |first3=Eric |last4=Korall |first4=Petra |last5=Schneider |first5=Harald |last6=Wolf |first6=Paul G. |date=August 2006 |title=A classification for extant ferns |url=https://www.fieldmuseum.org/sites/default/files/smith-et-al-taxon-2006.original.pdf |journal=Taxon |volume=55 |issue=3 |pages=705–731 |doi=10.2307/25065646 |jstor=25065646 |archive-url=https://web.archive.org/web/20211209070955/https://www.fieldmuseum.org/sites/default/files/smith-et-al-taxon-2006.original.pdf |archive-date=2021-12-09 |access-date=2016-12-22}}</ref> The linear sequence of Christenhusz et al. (2011), intended for compatibility with the classification of Chase and Reveal (2009)<ref name="christenhusz-etal-2011">{{Cite journal |last=Christenhusz |first=Maarten J. M. |author-link=Maarten J. M. Christenhusz |last2=Zhang |first2=Xian-Chun |last3=Schneider |first3=Harald |date=18 February 2011 |title=A linear sequence of extant families and genera of lycophytes and ferns |url=http://www.mapress.com/phytotaxa/content/2011/f/pt00019p054.pdf |journal=Phytotaxa |volume=19 |pages=7–54 |doi=10.11646/phytotaxa.19.1.2}}</ref> which placed all land plants in Equisetopsida,<ref>{{Cite journal |last=Chase |first=Mark W. |author-link=Mark Wayne Chase |last2=Reveal |first2=James L. |author-link2=James L. Reveal |date=October 2009 |title=A phylogenetic classification of the land plants to accompany APG III |journal=Botanical Journal of the Linnean Society |volume=161 |issue=2 |page=122 |doi=10.1111/j.1095-8339.2009.01002.x |doi-access=free}}</ref> reclassified Smith's Polypodiopsida as subclass Polypodiidae and placed the Cyatheales there. The circumscription of the order and its families was not changed.<ref name="christenhusz-etal-2011" /> The classification of Christenhusz and Chase (2014) placed all members of the Cyatheales in a more broadly defined Cyatheaeaceae, reducing the eight existing families to subfamilies as Thyrsopteridoideae, Loxsomatoideae, Culcitoideae, Plagiogyrioideae, Cibotioideae, Cyatheoideae, Dicksonioideae, and Metaxyoideae.<ref name="christenhusz-chase-2014">{{Cite journal |last=Christenhusz |first=Maarten J. M. |last2=Chase |first2=Mark W. |date=13 February 2014 |title=Trends and concepts in fern classification |journal=Annals of Botany |volume=113 |issue=4 |pages=571–594 |doi=10.1093/aob/mct299 |pmc=3936591 |pmid=24532607}}</ref> The PPG I classification (2016) returned to the eight-family definition of the order.,<ref name="PPGI">{{Cite journal |last=The Pteridophyte Phylogeny Group |date=November 2016 |title=A community-derived classification for extant lycophytes and ferns |url=https://www.researchgate.net/publication/309744599 |journal=Journal of Systematics and Evolution |volume=54 |issue=6 |pages=563–603 |doi=10.1111/jse.12229 |s2cid=39980610}}</ref> but this is not yet accepted by the general botanical community.
Historically, the Plagiogyriaceae were considered the single member of order Plagiogyriales, thought to be more closely related to Osmundales than to the tree ferns, but this hypothesis has been disproven by molecular phylogenetics.{{cn|date=June 2025}}
thumb|''Cyathea medullaris'' can grow up to 20 m tall in its native New Zealand.
{| class="wikitable" |- ! colspan=1 |Koral 2006, Koral 2007 & Lehtonen 2011<ref name=Koral-2007/><ref name=Koral-2006/><ref name=Lehtonen-2011/> ! colspan=1 |Nitta et al. 2022<ref>{{Cite journal |last=Nitta |first=Joel H. |last2=Schuettpelz |first2=Eric |last3=Ramírez-Barahona |first3=Santiago |last4=Iwasaki |first4=Wataru |display-authors=et al. |year=2022 |title=An Open and Continuously Updated Fern Tree of Life |journal=Frontiers in Plant Science |volume=13 |article-number=909768 |doi=10.3389/fpls.2022.909768 |pmc=9449725 |pmid=36092417 |doi-access=free}}</ref> and Fern Tree of life<ref>{{Cite web |display-authors=et al. |year=2023 |title=Tree viewer: interactive visualization of FTOL |url=https://fernphy.github.io/viewer.html |access-date=17 August 2023 |version=FTOL v1.5.0 [GenBank release 256]}}</ref> |- | style="vertical-align:top| {{clade|style=font-size:90%;line-height:80% |label1=Cyatheales |1={{clade |1={{clade |1=Thyrsopteridaceae |2={{clade |1=Loxsomataceae |2={{clade |1=Culcitaceae |2=Plagiogyriaceae }} }} }} |2={{clade |1=Cyatheaceae |2={{clade |1=Cibotiaceae |2={{clade |1=Dicksoniaceae |2=Metaxyaceae }} }} }} }} }} | {{Clade |style=font-size:90%;line-height:80% |label1=Cyatheales |1={{clade |1={{clade |1=Thyrsopteridaceae |2={{clade |1=Loxsomataceae |2={{clade |1=Culcitaceae |2=Plagiogyriaceae }} }} }} |2={{clade |1={{clade |1=Metaxyaceae |2=Cibotiaceae }} |2={{clade |1=Dicksoniaceae |2=Cyatheaceae }} }} }} }} |}
=== ''Incertae sedis'' fossil genera === * ''Alienopteris'' – Cerro Negro Formation, Antarctica, Early Cretaceous (Aptian) (stem) * ''Yavanna'' – Cerro Negro Formation, Antarctica, Early Cretaceous (Aptian) (stem) * ''Rafaherbstia'' – Cerro Negro Formation, Antarctica, Early Cretaceous (Aptian) (stem) * ''Natalipteris'' – Mzinene Formation?, South Africa, Cretaceous (Albian-Turonian) (stem) * ''Kwazulupteris'' – Mzinene Formation?, South Africa, Cretaceous (Albian-Turonian) (stem)
==Distribution and habitat== Tree ferns are found growing in tropical and subtropical areas, as well as temperate rainforests in South Africa, Australia, Spain, Portugal, New Zealand, and other island groups nearby; a few genera extend further, such as ''Culcita'' in southern Europe.{{cn|date=June 2025}}
While many ferns are able to achieve a widespread distribution because of their spore reproduction, tree fern species tend to be very local. This makes their species much more susceptible to the effects of local deforestation. Why species are not more widespread is unknown, especially considering they have sufficient height to have a greater chance of getting spores into the wind stream.{{Citation needed|date=May 2008}}
==Conservation== [[File:Fern Tree next to the Peak Tram road.jpg|thumb|right|A lone tree fern next to the Peak Tram line on Hong Kong Island]] Where feral pigs are a problem, as in some Hawaiian rainforests, they will knock over tree ferns to root out the starchy pith, killing the plant.<ref>{{Cite book |last=Baskin |first=Yvonne |title=A Plague of Rats and Rubbervines: The Growing Threat of Species Invasions |publisher=Island Press |year=2003 |isbn=978-1-55963-051-1 |pages=74–75}}</ref> {{clear}}
==References== {{Reflist|refs= <ref name="Koral-2006">{{Cite journal |last=Korall |first=Petra |last2=Pryer |first2=Kathleen M. |last3=Metzgar |first3=Jordan S. |last4=Schneider |first4=Harald |last5=Conant |first5=David S. |year=2006 |title=Tree ferns: Monophyletic groups and their relationships as revealed by four protein-coding plastid loci |url=http://www.pryerlab.net/publication/fichier734.pdf |journal=Molecular Phylogenetics and Evolution |volume=39 |issue=3 |pages=830–845 |doi=10.1016/j.ympev.2006.01.001 |pmid=16481203}}</ref> <ref name="christenhusz-chase-2014">{{Cite journal |last=Christenhusz |first=Maarten J. M. |last2=Chase |first2=Mark W. |date=13 February 2014 |title=Trends and concepts in fern classification |journal=Annals of Botany |volume=113 |issue=4 |pages=571–594 |doi=10.1093/aob/mct299 |pmc=3936591 |pmid=24532607}}</ref> <ref name="Lehtonen-2011">{{Cite journal |last=Lehtonen |first=Samuli |year=2011 |title=Towards Resolving the Complete Fern Tree of Life |journal=PLOS ONE |volume=6 |issue=10 |article-number=e24851 |bibcode=2011PLoSO...624851L |doi=10.1371/journal.pone.0024851 |pmc=3192703 |pmid=22022365 |doi-access=free}}</ref>
<ref name="Koral-2007">{{Cite journal |last=Korall |first=Petra |last2=Conant |first2=David S. |last3=Metzgar |first3=Jordan S. |last4=Schneider |first4=Harald |last5=Pryer |first5=Kathleen M. |year=2007 |title=A Molecular phylogeny of scaly tree ferns (Cyatheaceae) |journal=American Journal of Botany |volume=94 |issue=5 |pages=873–886 |doi=10.3732/ajb.94.5.873 |pmid=21636456}}</ref> }} * {{Cite journal |last=Pryer |first=K.M. |last2=Smith |first2=A.R. |last3=Skog |first3=J.E. |year=1995 |title=Phylogenetic relationships of extant ferns based on evidence from morphology and rbcL sequences |url=https://www.biodiversitylibrary.org/part/230658 |journal=American Fern Journal |volume=85 |issue=4 |pages=205–282 |doi=10.2307/1547810 |jstor=1547810}} * C.Michael Hogan. 2010. [https://web.archive.org/web/20111109071540/http://www.eoearth.org/article/Fern ''Fern''. Encyclopedia of Earth. National council for Science and the Environment]. Washington, DC * Large, M.F. and J.E. Braggins ''Tree Ferns''. Timber Press (2004). * Smith, A.R., K.M. Pryer, E. Schuettpelz, P. Korall, H. Schneider & P.G. Wolf 2006. {{Cite web |title=A classification for extant ferns. |url=http://www.pryerlab.net/publication/fichier749.pdf |archive-url=https://web.archive.org/web/20080226232147/http://www.pryerlab.net/publication/fichier749.pdf |archive-date=2008-02-26}} {{small|(420 KiB)}} ''Taxonomy'' '''55'''(3): 705–731.
==External links== {{Sister project links|wikt=no|c=yes|n=no|q=no|s=no|b=no|v=no|species=yes|m=no}} * [https://web.archive.org/web/20050908055016/http://www.baumfarn.at/treefern/ Community: Care and propagation of Treeferns] (German/English) * [https://web.archive.org/web/20121020134615/http://www.forestferns.co.uk/tree-ferns/cyathea Fern Files: Tree Ferns]
{{Plant classification}} {{Fern classification}} {{Taxonbar|from=Q623232}} {{Authority control}}
Category:Cyatheales Category:Fern orders