{{Short description|Species of fern in the spleenwort family}} {{Speciesbox | image = Asplenium trichomanes IMG 7821 Langaara Asker Norway.JPG | image_caption = ''Asplenium trichomanes'' subsp. ''trichomanes'', Langaara, Oslo Fjord, Norway | status = {{TNCStatus}} | status_system = TNC | status_ref = <ref>{{cite NatureServe |id=2.129841 |title=''Asplenium trichomanes'' |date=November 1, 2024 |access-date=November 16, 2024}}</ref> | genus = Asplenium | species = trichomanes | authority = L. | subdivision_ranks = Infraspecific taxa | subdivision = See text }}

'''''Asplenium trichomanes''''', the '''maidenhair spleenwort''' (not to be confused with the similarly-named but very different maidenhair fern),<ref name=BSBI07>{{BSBI 2007 |accessdate=2014-10-17 }}</ref> is a small fern in the spleenwort genus ''Asplenium''. It is a widespread and common species, occurring almost worldwide in a variety of rocky habitats. It is a variable fern with several subspecies.

The specific epithet ''trichomanes'' refers to a Greek word for fern.<ref name=RHSLG>{{cite book |last=Harrison |first=Lorraine |title=RHS Latin for Gardeners |year=2012 |publisher=Mitchell Beazley |location=United Kingdom |isbn=978-1845337315 }}</ref>

==Description== left|thumb|Sori on the underside of the frond ''Asplenium trichomanes'' is a small plant forming tufts between {{cvt|10|and|30|cm}} tall, arising from a short, scaly rhizome. The scales are dark and the evergreen fronds are long and narrow, gradually tapering towards the tip. They are simply divided into small, yellow-green to dark-green, roundish leaflets or pinnae. The stipe and rachis of the frond are dark all along their length. The fronds can reach {{cvt|40|cm}} in length but are more commonly between {{cvt|8|and|20|cm}}. The indusia are linear to oval, straight, and attached to the upper-side of the fertile vein. There are usually four to eight sori per pinna, and each may be up to {{cvt|3.5|mm|2}} long. The diploid (2n) chromosome count is 72.<ref name="CoffinPfannmuller1988">{{cite book|author1=Barbara Coffin|author2=Lee Pfannmuller|title=Minnesota's Endangered Flora and Fauna|url=https://books.google.com/books?id=wfWNq91AjeoC|year=1988|publisher=U of Minnesota Press|isbn=978-0-8166-1689-3|page=56}}</ref><ref>{{Cite web|title=Asplenium trichomanes L.|url=http://www.worldfloraonline.org/taxon/wfo-0001109364|access-date=2020-12-05|website=www.worldfloraonline.org}}</ref> It is known to display foliage motion; in this regard it resembles the unrelated ''Codariocalyx motorius'' though this has its leaflets in motion much of the time.<ref>{{cite journal | last= Gray | first= Asa | last2= Loomis | first2= Alfred | date= March 1880 | title= Automatic Movements in the Fronds...etc.| journal= Botanical Gazette | volume= 5 | issue= 3 | page= 27}}</ref><ref>{{cite journal | last= Gray | first= Asa | last2= Loomis | first2= Alfred | date= April 1880 | title= Automatic Movements in the Fronds...etc.| journal= Botanical Gazette | volume= 5 | issue= 4 | page= 43}} issue 4 (April 1880) page 43</ref>

==Distribution and habitat== It is widespread in temperate and subarctic areas and also occurs in mountainous regions in the tropics. Its range includes most of Europe and much of Asia south to Turkey, Iran and the Himalayas with a population in Yemen. It occurs in northern, southern and parts of eastern Africa and also in eastern Indonesia, south-east Australia, Tasmania, New Zealand and Hawaii. It is found in North America and Central America and Cuba, and the northern and western regions of South America such as Chile. Even though its range is wide spread, it is often rare, and populations are widely spread out from each other based on the availability of suitable habitat.<ref name="CoffinPfannmuller1988"/>

It grows in rocky habitats such as cliffs, scree slopes, walls and mine waste, the type of rock used as a substrate depending on the subspecies. It grows from sea-level up to 3000 metres in North America while in the British Isles it reaches 870 metres.

In the US state of Minnesota ''A. trichomanes'' is listed as a threatened species. It occurs on ledges and in crevices on moist, east-facing cliffs and occasionally on talus with similar conditions. The Minnesota populations are ''Asplenium trichomanes'' subsp. ''trichomanes''.<ref name="CoffinPfannmuller1988"/>

==Taxonomy== thumb|''Asplenium trichomanes'' subsp. ''quadrivalens'', Austria Linnaeus was the first to describe maidenhair spleenwort with the binomial ''Asplenium trichomanes'' in his ''Species Plantarum'' of 1753.<ref>{{cite book | title=Species Plantarum | edition=1st | volume=II | last=Linnaeus | first=C. | authorlink=Carl Linnaeus | year=1753 | publisher=Laurentii Salvii | location=Stockholm | url=https://www.biodiversitylibrary.org/page/359101|page=1080}}</ref>

''Asplenium trichomanes'' has diploid, tetraploid and hexaploid cytotypes, which it has been argued should be recognised as distinct species. A triploid cytotype (a sterile hybrid between the diploid and tetraploid cytotype) is also known. Within these cytotypes several subspecies are recognised. ''Plants of the World Online'' accepts 20 infraspecific subdivisions {{As of|2025|2|lc=y}}.<ref name = powo>{{cite web |title=''Asplenium trichomanes'' L. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:310197-2 |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=3 February 2025}}</ref> These include:

*''Asplenium trichomanes'' subsp. ''trichomanes'' prefers acidic rocks such as sandstone, basalt and granite. In Europe and North America it is most often found in mountainous areas and is commonest in the north. It is a delicate plant with a slender stipe and rachis and relatively few pinnae. Diploid. *''Asplenium trichomanes'' subsp. ''quadrivalens'' {{small|D.E.Mey.}} prefers calcareous rocks such as limestone and dolomite and often grows on the mortar in walls. It is commoner than ''A. t.'' subsp. ''trichomanes'' in much of Europe but is less widespread in North America, although it is present in southern North America where ssp. ''trichomanes'' is absent. Compared to the nominate subspecies it is stouter and has more pinnae which are more square in shape and have less of a stalk. The fronds tend to grow close to the rock while those of ''A. t.'' subsp. ''trichomanes'' tend to arch away. Tetraploid. *''Asplenium trichomanes'' subsp. ''pachyrachis'' {{small|(Christ) Lovis & Reichst.}} (syn. ''Asplenium csikii'') is mainly found on limestone rocks and walls. It is small and delicate, grows close to the rock and has a rigid, fragile stipe and rachis. Tetraploid. *''Asplenium trichomanes'' subsp. ''coriaceifolium'' {{small|Rasbach, K.Rasbach, Reichst. & Bennert}} (syn. ''Asplenium azomanes''): Majorca, Spain, Morocco. Tetraploid. *''Asplenium trichomanes'' subsp. ''densum'' {{small|(Brack.) W.H.Wagner}} – Hawaiian Islands *''Asplenium trichomanes'' subsp. ''hastatum'' {{small|(Christ) S.Jess.}}. Tetraploid. *''Asplenium trichomanes'' subsp. ''humistratum'' {{small|(Ching) Fraser-Jenk.}} *''Asplenium trichomanes'' subsp. ''inexpectans'' {{small|Lovis}}. Diploid. *''Asplenium trichomanes'' subsp. ''kulumyssiense'' {{small|Stepanov}} *''Asplenium trichomanes'' subsp. ''maderense'' {{small|Gibby & Lovis}}. Madeira, Azores. Hexaploid. Hexaploids also occur in Australia and New Zealand. *''Asplenium trichomanes'' nothosubsp. ''barraraense'' {{small|Rasbach, K.Rasbach, Reichst. & Bennert}}. Tetraploid (''coraceifolium'' × ''quadrivalens'') – Balearic Islands *''Asplenium trichomanes'' nothosubsp. ''lovisianum''. Tetraploid (''hastatum'' × ''quadrivalens''). *''Asplenium trichomanes'' nothosubsp. ''lucanum'' {{small|Cubas, Rosselló & Pangua}} – Balearic Islands *''Asplenium trichomanes'' nothosubsp. ''lusaticum'' {{small|(D.E.Mey.) Lawalrée}}. Triploid (''trichomanes'' × ''quadrivalens''). *''Asplenium trichomanes'' nothosubsp. ''malacitense'' {{small|Rasbach, K.Rasbach, Reichst. & Bennert}}. Triploid (''coraceifolium'' × ''inexpectans''). *''Asplenium trichomanes'' nothosubsp. ''melzeri'' {{small|Lovis, Rasbach & Reichst.}}. Triploid (''quadrivalens'' × ''inexpectans''). *''Asplenium trichomanes'' nothosubsp. ''melzerianum'' {{small|S.Jess.}}. Triploid (''hastatum'' × ''inexpectans''). *''Asplenium trichomanes'' nothosubsp. ''moravicum'' {{small|S.Jess.}}. Tetraploid (''hastatum'' × ''pachyrachis''). *''Asplenium trichomanes'' nothosubsp. ''staufferi'' {{small|Lovis & Reichst.}}. Tetraploid (''pachyrachis'' × ''quadrivalens''). *''Asplenium trichomanes'' nothosubsp. ''tadei-reichsteinii'' {{small|S.Jess.}}. Triploid (''pachyrachis'' × ''inexpectans'').

==Cultivation== ''Asplenium trichomanes'' is valued in cultivation for its hardiness (down to {{convert|-20|C|F}}), its evergreen foliage and its ability to colonise crevices in stone walls. It prefers a fully or partially shaded aspect. It has gained the Royal Horticultural Society's Award of Garden Merit.<ref name = RHSPF>{{cite web | url= https://www.rhs.org.uk/Plants/1731/i-Asplenium-trichomanes-i/Details |title = RHS Plantfinder - ''Asplenium trichomanes'' | publisher = Royal Horticultural Society | accessdate=12 January 2018}}</ref>

==References== {{Reflist}} *Flora of North America. [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200004180 ''Asplenium trichomanes'']. Accessed 13 August 2008. *Hutchinson, G. (1996) ''Welsh Ferns'', National Museums and Galleries of Wales. *Page C. N. (1982) ''The Ferns of Britain and Ireland'', Cambridge University Press. *Preston, C. D. & Pearman, D. A. (2002) ''New Atlas of the British and Irish Flora'', Oxford University Press. *Stace, Clive A. (1997) ''New Flora of the British Isles'', Cambridge University Press. *Tutin, T. G. ''et al.'' (1964) ''Flora Europaea'', Volume 1. Cambridge University Press.

==External links== {{Commons}} *[http://bsbi.org/maps?taxonid=2cd4p9h.aq BSBI Maps: Distribution in Britain and Ireland] *[http://www.pfaf.org/database/plants.php?Asplenium+trichomanes Plants for a Future database] *[https://www.paenflowered.org/apgii/polypodiales/aspleniaceae/asplenium/asplenium-trichomanes Flora of Pennsylvania]

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trichomanes Category:Ferns of the Americas Category:Ferns of Asia Category:Ferns of Europe Category:Ferns of Australasia Category:Ferns of the United States Category:Alpine flora Category:Tropical flora Category:Flora of Central America Category:Flora of Southern America Category:Flora of Australasia Category:Flora of Asia Category:Flora of Australia Category:Plants described in 1753 Category:Botanical taxa named by Carl Linnaeus Category:Flora of Hawaii