Editing Equisetum (section)

==Distribution and ecology==
The genus ''Equisetum'' as a whole, while concentrated in the non-tropical northern hemisphere, is near-[[cosmopolitan distribution|cosmopolitan]], being absent naturally only from [[Antarctica]], [[Australia]], [[New Zealand]], and the islands of the [[Pacific Ocean]]. They are most common in northern Europe, with ten species (''E.&nbsp;arvense'', ''E.&nbsp;fluviatile'', ''E.&nbsp;hyemale'', ''E.&nbsp;palustre'', ''E.&nbsp;pratense'', ''E.&nbsp;ramosissimum'', ''E.&nbsp;scirpoides'', ''E.&nbsp;sylvaticum'', ''E.&nbsp;telmateia'', and ''E.&nbsp;variegatum''); [[Great Britain]] has nine of these species, missing only ''E.&nbsp;scirpoides'' of the European list.<ref name="Fitter">{{cite book |last1=Fitter |first1=Richard |last2=Fitter |first2=Alastair |last3=Farrer |first3=Anne |title=Collins Guide to the Grasses, Sedges, Rushes and Ferns of Britain and Northern Europe |date=1984 |publisher=Collins |location=London |isbn=0-00-219136-9 |pages=188–191}}</ref><ref name = Streeter/> Northern North America (Canada and the northernmost United States), also has nine species (''E.&nbsp;arvense'', ''E.&nbsp;fluviatile'', ''E.&nbsp;laevigatum'', ''E.&nbsp;palustre'', ''E.&nbsp;praealtum'', ''E.&nbsp;pratense'', ''E.&nbsp;scirpoides'', ''E.&nbsp;sylvaticum'', and ''E.&nbsp;variegatum''). Only five (''E.&nbsp;bogotense'', ''E.&nbsp;giganteum'', ''E.&nbsp;myriochaetum'', ''E.&nbsp;ramosissimum'', and ''E.&nbsp;xylochaetum'') of the eighteen species are known to be native south of the Equator.

They are [[perennial plant]]s, [[Herbaceous plant|herbaceous]] and dying back in winter in most temperate species, or [[evergreen]] as most tropical species and the temperate species ''[[Equisetum hyemale|E.&nbsp;hyemale]]'' (rough horsetail), ''[[Equisetum ramosissimum|E.&nbsp;ramosissimum]]'' (branched horsetail), ''[[Equisetum scirpoides|E.&nbsp;scirpoides]]'' (dwarf horsetail) and ''[[Equisetum variegatum|E.&nbsp;variegatum]]'' (variegated horsetail). They typically grow 20&nbsp;cm–1.5&nbsp;m (8&nbsp;in–5&nbsp;ft) tall, though the subtropical "giant horsetails" are recorded to grow as high as {{cvt|5|m|ft|0}} (''[[Equisetum giganteum|E.&nbsp;giganteum]]'', southern giant horsetail) or {{cvt|8|m|ft|0}} (''[[Equisetum myriochaetum|E.&nbsp;myriochaetum]]'', Mexican giant horsetail), and allegedly even more.<ref>{{cite web |last1=Husby |first1=Chad E. |title=How large are the giant horsetails? |url=http://www.fiu.edu/~chusb001/GiantEquisetum/HowLarge.html |website=The Giant Horsetails |access-date=20 November 2008 |archive-url=https://web.archive.org/web/20040411005228/http://www.fiu.edu/~chusb001/GiantEquisetum/HowLarge.html |archive-date=11 April 2004 |date=2003}}</ref>

One species, ''[[Equisetum fluviatile]]'', is an emergent [[Aquatic plant|aquatic]], rooted in water with shoots growing into the air. The stalks arise from [[rhizome]]s that are deep underground and difficult to dig out. Field horsetail (''[[Equisetum arvense|E.&nbsp;arvense]]'') can be a nuisance [[weed]], readily regrowing from the rhizome after being pulled out. It is unaffected by many [[herbicide]]s designed to kill [[Spermatophyte|seed plants]].<ref>{{cite web|url=https://oregonstate.edu/dept/nursery-weeds/weedspeciespage/horsetail/Equisetum_arvense_horsetail.html|title=Horsetail - 'Equisetum arvense'|date=2003|first=James|last=Altland|access-date=2019-07-17|website=oregonstate.edu|archive-date=2018-11-14|archive-url=https://web.archive.org/web/20181114181423/http://oregonstate.edu/dept/nursery-weeds/weedspeciespage/horsetail/Equisetum_arvense_horsetail.html|url-status=dead}}</ref>{{citation needed|date=August 2016}} Since the stems have a waxy coat, the plant is resistant to contact weedkillers like glyphosate.<ref>{{cite web|title=Control Horse or Mare's Tail - Equisetum Arvense|url=https://www.allotment-garden.org/gardening-information/weed-control/control-horse-mares-tail-equisetum-arvense/|department=Controlling Horsetail with Contact Herbicides|date=2016|website=allotment-garden.org|access-date=2019-07-17}}</ref> However, as ''E.&nbsp;arvense'' prefers an acid soil, [[Agricultural lime|lime]] may be used to assist in eradication efforts to bring the [[soil pH]] to 7 or 8.<ref>{{cite web |last1=Kress |first1=Henriette |title=Getting rid of horsetail |url=https://www.henriettes-herb.com/blog/getting-rid-horsetail.html |website=Henriette's Herbal Homepage |access-date=19 May 2010 |date=7 April 2005}}</ref> Members of the genus have been declared noxious weeds in [[Australia]] and in the US state of [[Oregon]].<ref name=aus>{{cite book|title=Noxious weeds of Australia|url=https://books.google.com/books?id=sRCrNAQQrpwC&q=Equisetum%20australia&pg=PA14|publisher=CSIRO Publishing |year=2001|page=14|author1=William Thomas Parsons |author2=Eric George Cuthbertson |isbn=978-0-643-06514-7}}</ref><ref>{{cite web|title=''Equisetum telmateia'' Ehrh. giant horsetail|url=http://plants.usda.gov/java/profile?symbol=EQTE|publisher=[[USDA]]|access-date=2010-05-18}}</ref>

All the ''Equisetum'' are classed as "unwanted organisms" in [[New Zealand]] and are listed on the [[National Pest Plant Accord]].<ref>{{cite web|title=National Pest Plant Accord|url=http://www.rnzih.org.nz/pages/accord.pdf|date=2001|website=rnzih.org.nz|access-date=2019-07-17}}</ref>