{{short description|Species of vascular plant in the horsetail family}} {{Italic title}} {{Speciesbox | name = Marsh horsetail | image = equisetum_palustre_detail.jpeg | image_caption = ''Equisetum palustre'' | status = {{TNCStatus}} | status_system = TNC | parent = Equisetum subg. Equisetum | genus = Equisetum | species = palustre | authority = L. | synonyms_ref = <ref name=POWO_30039890-2>{{Cite POWO|title=''Equisetum palustre'' L..|id=30039890-2|access-date=2024-09-17|mode=cs1}}</ref> | synonyms = {{Species list|hidden=yes |Equisetum aquatile|Scheller, nom. superfl. |Equisetum arenarium|Opiz |Equisetum hybridum|Huter |Equisetum limosum var. minus|Roth |Equisetum nodosum|Hoppe |Equisetum palustre subvar. apiculatum|Coss. & Germ. |Equisetum palustre var. americanum|Vict. |Equisetum palustre var. aphyllum|Lej. |Equisetum palustre var. apiculatum|(Coss. & Germ.) Rouy |Equisetum palustre var. arcuatum|Milde |Equisetum palustre var. collinum-tenerrimum|Schur |Equisetum palustre var. japonicum|Nakai |Equisetum palustre var. leptostachyum|Wallr., nom. superfl. |Equisetum palustre var. membranaceum|Lej. |Equisetum palustre var. microstachyum|Schur |Equisetum palustre var. nanum|Milde |Equisetum palustre var. nigridens|H.St.John |Equisetum palustre var. nudum|Duby, nom. illeg. |Equisetum palustre var. nudum|Opiz |Equisetum palustre var. paludosum|Schur |Equisetum palustre var. polystachion|Gray |Equisetum palustre var. polystachyum|A.Braun & Engelm., nom. illeg. |Equisetum palustre var. polystachyum|Weigel |Equisetum palustre var. prostratum|Brause, nom. illeg. |Equisetum palustre var. ramosissimum|M.Peck |Equisetum palustre var. ramosum|Opiz |Equisetum palustre var. ramulosum|Milde |Equisetum palustre var. simplex|Rupr. |Equisetum palustre var. simplicissimum|A.Braun & Engelm. |Equisetum palustre var. szechuanense|C.N.Page |Equisetum palustre var. tenue|Döll |Equisetum palustre var. tenuissimum|Gray |Equisetum torgesianum|Rothm. |Equisetum tuberosum|Hectot ex DC. |Equisetum veronense|Pollini |Presla palustris|(L.) Dulac }} }}
'''''Equisetum palustre''''', the '''marsh horsetail''',<ref name=BSBI07>{{BSBI 2007 |accessdate=2014-10-17 }}</ref> is a perennial herbaceous pteridophyte belonging to the subclass of horsetails (Equisetidae). It is widespread in cooler regions of Eurasia and North America.<ref name=POWO>{{cite web |title=''Equisetum palustre'' L. |work=Plants of the World Online |publisher=Royal Botanic Gardens, Kew|url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30039890-2 |access-date=2024-09-16 }}</ref><ref>[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500621 Flora of North America, Marsh horsetail, prêle des marais, ''Equisetum palustre'' Linnaeus, Sp. Pl. 2: 1061. 1753. ]</ref><ref>[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=233500621 Flora of China, <big>犬问荆</big> quan wen jing ''Equisetum palustre'' Linnaeus]</ref>
== Description == ''Equisetum palustre'' has stems growing between 10-60 cm tall. The upright stems are usually scarcely branched with loose green leaf sheaths that have 5-10 narrow, dark teeth. The teeth are light at the edges. The lowest internode of the upright branches are much shorter than the leaf sheath of the stem.<ref name=hwh>Hyde, H. A., Wade, A. E., & Harrison, S. G. (1978). ''Welsh Ferns''. National Museum of Wales {{ISBN|0-7200-0210-9}}.</ref><ref name="Piirainen">{{cite book |last1=Piirainen |first1=Mikko |title=Kotimaan luonnonkasvit |last2=Piirainen |first2=Pirkko |last3=Vainio |first3=Hannele |date=1999 |publisher=WSOY |isbn=951-0-23001-4 |location=Porvoo, Finland |page=22 |language=fi |trans-title=Native wild plants}}</ref>
The rough, furrowed stem is 1–3 mm diameter, with usually 8–10 ribs, in rare cases, 4–12; it bears a variable number of whorled branches.<ref name=hwh/>
The spores are spread by the wind (anemochory) and have four long ribbon-like structures attached to them. The spores sit on strobili which are rounded on the top. Marsh horsetails often form runners, with which they also can proliferate vegetatively.<ref name="Piirainen" />
==Taxonomy== Linnaeus was the first to describe marsh horsetail with the binomial ''Equisetum palustre'' 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/359082|page=1061}}</ref>
== Ecology == ''Equisetum palustre'' is green from spring to autumn and grows spores from June to September. <!-- translated from German, dates may vary --> It grows primarily in nutrient-rich wet meadows. It is found in Europe and the circumpolar region up to mountainous heights. Its distribution is declining.{{Citation needed|date=April 2024}}
In Finland, it has benefited from human action and grows often in road and track sides, ditches and especially peat based fields and pastures.<ref name="Piirainen" />
A specific plant association in which ''E. palustre'' is found is the ''Juncus subnodulosus''-''Cirsium palustre'' fen-meadow.<ref>{{Cite web |date=2012-12-13 |title=Marsh Thistle (Cirsium palustre) - photo/images/information - GlobalTwitcher.com |url=http://www.globaltwitcher.com/artspec_information.asp?thingid=48639 |access-date=2024-04-16 |archive-url=https://web.archive.org/web/20121213144520/http://www.globaltwitcher.com/artspec_information.asp?thingid=48639 |archive-date=2012-12-13 }}</ref>
== Toxicity == ''Equisetum palustre'' is poisonous to mammals, most often reported as potentially fatal to horses, as it contains alkaloids palustrine and palustridiene, which destroy vitamin B<sub>1</sub>. According to Wink, ''Equisetum palustre'' also contains thiaminase enzymes. It is also known to contain lesser amounts of nicotine. Many thiaminases, however, are denatured by heat, and some sources refer ''Equisetum palustre'' safe to eat in moderate amounts when properly cooked.<ref>''https://www.mdpi.com/2072-6651/12/11/710/h{{Dead link|date=January 2026 |bot=InternetArchiveBot }}tm'' Variation of the Main Alkaloid Content in Equisetum palustre L. in the Light of Its Ontogeny</ref><ref>''https://core.ac.uk/download/pdf/235685921.pdf'' Heidelberg University, Institute of Pharmacy and Molecular Biotechnology (2009). Mode of action and toxicology of plant toxins and poisonous plants</ref><ref>''https://pfaf.org/user/Plant.aspx?LatinName=Equisetum+palustre'' Plants for Future</ref><ref>''https://poisonousplants.ansci.cornell.edu/toxicagents/thiaminase.html'' Cornell University, Department of Animal Science - Plants Poisonous to Livestock</ref> In Finland, it used to lower the production of dairy when cows would eat them in place of other preferable fodder.<ref name="Piirainen" />
== Gallery == <gallery> File:EquisetemPalustreKythira.jpg|Marsh horsetail in Kythira </gallery>
==References== {{Reflist}} * [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500621 Flora of North America: ''Equisetum palustre'']
== External links == * Walkowiak R. J., ''[https://www.researchgate.net/publication/335995986_Equisetum_palustre_IEA_Collection_of_Equisetum_2019 Equisetum palustre L.]'', IEA Collection of Equisetum, 2019
{{Commons category-inline|Equisetum palustre}}{{Taxonbar|from=Q21122}}
palustre Category:Plants described in 1753 Category:Botanical taxa named by Carl Linnaeus Category:Flora of Northern America Category:Flora of Europe Category:Flora of Asia