{{short description|Species of flowering plant in the family Polygonaceae}} {{Use dmy dates|date=September 2021}} {{speciesbox |name = Broad-leaved dock |image = Rumex-obtusifolius-foliage.JPG |genus = Rumex |species = obtusifolius |authority = L. |synonyms = ''Rumex sylvestris'' (Lam.) Campd.<ref name="eea.europa.eu">{{cite web |title=Rumex sylvestris – Wallr. |url=https://eunis.eea.europa.eu/species/177547 |website=eunis.eea.europa.eu |access-date=14 February 2021}}</ref> }}
'''''Rumex obtusifolius''''', commonly known as '''bitter dock''',<ref name="cabi">{{Cite web|title=''Rumex obtusifolius'' (broad-leaved dock)|url=https://www.cabi.org/isc/datasheet/48064|date=22 November 2019|publisher=CAB International|access-date=30 April 2020}}</ref><ref>{{PLANTS|id=RUOB|taxon=Rumex obtusifolius|access-date=26 October 2015}}</ref> '''broad-leaved dock''', '''bluntleaf dock''', '''dock leaf''', '''dockens''' or '''butter dock''', is a perennial plant in the family Polygonaceae. It is native to Europe, but is found on all temperate continents.<ref name=cabi/><ref name="australiadockobtusifolius">{{cite web | url=http://keyserver.lucidcentral.org/weeds/data/03030800-0b07-490a-8d04-0605030c0f01/media/Html/Rumex_obtusifolius_subsp._obtusifolius.htm | title=Broad-leaved dock | publisher=Queensland Government | access-date=17 March 2016 | archive-date=21 September 2015 | archive-url=https://web.archive.org/web/20150921171836/http://keyserver.lucidcentral.org/weeds/data/03030800-0b07-490a-8d04-0605030c0f01/media/Html/Rumex_obtusifolius_subsp._obtusifolius.htm | url-status=dead }}</ref><ref name="nzobtusifolius">{{cite web | url=http://www.massey.ac.nz/massey/learning/colleges/college-of-sciences/clinics-and-services/weeds-database/broad-leaved-dock.cfm | title=Broad-leaved dock | publisher=Massey University (New Zealand) | access-date=17 March 2016}}</ref> It is a highly invasive species in some zones, resulting from its abundant seed dispersal, adaptability to reproduce, aggressive roots, ability to tolerate extreme climates, and hardiness.<ref name=cabi/>
==Etymology== The name, ''Rumex obtusifolius'', was assigned by Carl Linnaeus in the 18th century, and has remained unchanged, although there are numerous subspecies.<ref name=cabi/> ''Rumex'' was Pliny's name for sorrel,<ref name="gledhill">Gledhill, David (2008). "The Names of Plants". Cambridge University Press. {{ISBN|9780521866453}} (hardback), {{ISBN|9780521685535}} (paperback). pp 277, 335</ref> while ''obtusifolius'' means 'obtuse-leaved' (obtuse + foliage).<ref name=cabi/><ref name="gledhill" /> thumb|Botanical illustration of ''Rumex obtusifolius''
==Description== ''Rumex obtusifolius'' is a perennial herbaceous flowering plant that grows to a height of {{convert|40|to|150|cm|0|abbr=on}}.<ref name=cabi/> It is easily recognizable by its very large oval leaves with cordate bases and rounded tips, some of the lower leaves having red stems.<ref name=cabi/> The edges of the leaves are slightly "crisped" or wavy, the upper surface is hairless and the under surface may be papillose.<ref name=cabi/> The leaves of this plant can grow to about {{convert|30|cm|0|abbr=on}} in length and {{convert|15|cm}} wide.<ref name=cabi/> The taproot is large, with numerous branches extending to a depth of {{convert|150|cm}}, with tough stems, often reddish, and unbranched until just below the inflorescence.<ref name=cabi/>
The junctions of the petioles with the stems are covered by a sheath formed by two fused stipules known as an ocrea, a thin, paper-like membrane – a characteristic of the family Polygonaceae. The stem leaves are alternate and are narrowly ovate–lanceolate. The inflorescence consists of large clusters of racemes which contain small greenish flowers that change to red as they mature. The perianth-segments are in two whorls of three. Segments in the outer whorl are small and spreading while the inner whorl forms fruit valves, which are widely ovately-triangular. The seeds produced are dry and reddish brown. This plant blooms June through September.<ref name=NatureGate>{{cite web |url=http://www.luontoportti.com/suomi/en/kukkakasvit/broad-leaved-dock |title=Broad-leaved Dock: ''Rumex obtusifolius'' |publisher=NatureGate |access-date=30 December 2013}}</ref>
''Rumex crispus'' – curly dock – is similar in appearance, but with thinner and wave-like leaves. In more detail, the calyx of curly dock has smooth margins while the calyx of broad-leaved dock has horned margins.{{citation needed|date=April 2020}}
==Distribution and habitat== ''Rumex obtusifolius'' is widely distributed throughout the world.<ref name=cabi/> It is a plant growing readily on arable land, meadows, waste ground, roadsides, ditches, shorelines, riverbanks, woodland margins, forest clearings, and orchards.<ref name=cabi/><ref name=NatureGate/> Seedlings can be identified by the oval leaves with red stems and rolled leaves sprouting from the center of the plant. Regrowth from the rosette usually takes place in spring.<ref name=cabi/>
==Uses==
Leaves of the plant can be used as salad,<ref name=cabi/>{{Failed verification|date=May 2025|reason=Section "Uses" does not specify salad: "R. obtusifolius is used in the traditional diet of rural Greece as a wild edible green, consumed in various ways." If another section specifies it, please add a quote in a citation.}} to prepare a vegetable broth or to be cooked like spinach. They contain oxalic acid which can be hazardous if consumed in large quantities.<ref>Vasas, A., Orbán-Gyapai, O. and Hohmann, J., 2015. The Genus ''Rumex'': Review of traditional uses, phytochemistry and pharmacology. ''Journal of ethnopharmacology'', 175, pp.198-228.</ref> The dried seeds can be ground to make flour. In Turkey, Romania and Greece the leaves are sometimes used as an alternative to other plants in the making of sarmale. A tea prepared from the root was thought to cure boils.<ref>[http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=220 Ohio Perennial and Biennial Weed Guide<!-- Bot generated title -->]</ref>
In Ireland and the United Kingdom, the plant is often found growing near stinging nettles and there is a widely held belief that the underside of the dock leaf, squeezed to extract a little juice, can be rubbed on the skin to counteract the itching caused by brushing against a nettle plant.<ref>{{Cite web|title=Plants|url=https://www.duchas.ie/en/cbes/4428244/4388039/4510354 |website=The Schools' Collection}}{{unreliable source?|date=June 2021}}</ref><ref>{{cite web |work=Ethnomedica |url=http://www.rbgkew.org.uk/ethnomedica/reports/dock.html |title=Recorded uses of' dock (''Rumex'' sp.) |access-date=15 April 2008 |url-status=usurped |archive-url=https://web.archive.org/web/20081120040109/http://www.rbgkew.org.uk/ethnomedica/reports/dock.html |archive-date=20 November 2008}} {{verify source |date=September 2019}}</ref> This home remedy is not supported by any science, although it is possible that the act of rubbing may act as a distracting counterstimulation, or that belief in the dock's effect may provide a placebo effect.<ref>{{cite news |last1=Hopcroft |first1=Keith |title=Home remedies: dock leaves for nettle stings |url=https://www.thetimes.com/article/home-remedies-dock-leaves-for-nettle-stings-gk075bw6b3c |access-date=29 August 2020 |date=10 September 2005 |language=en}}</ref>
===History===
In George Eliot's ''Adam Bede'', set in the early 19th century, broad dock leaves were used to wrap farmhouse butter.<ref>Eliot, George (1859). ''Adam Bede'' (Modern Library, 2002); p93-94.</ref>
===Host plant=== ''Rumex obtusifolius'' is a major host plant for many different insects as well, including the ''Acronicta rumicis'' moth. For ''A. rumicis'' research, this host plant is generally targeted because it is found highly within the moth's range.<ref>Cho, Y., Kwon, O. & Nam, S.-H., 2006. Ecological and morphological characteristics of the endoparasitoids of larval ''Acronicta rumicis'' (Lepidoptera: Noctuidae). ''Entomological Research'', 36, pp. 208–215.</ref>
==Invasiveness and eradication==
''Rumex obtusifolius'' is an aggressive invasive species on all temperate continents.<ref name=cabi/> Broad-leaved dock is designated an "injurious weed" under the UK Weeds Act 1959.<ref name=cabi/> It has been an invasive species of the Great Lakes region of North America where it was first sighted in 1840.<ref>{{cite web |title= List of Invasive species in the Great Lakes Great Lakes United / Union Saint-Laurent Grands Lacs |url= http://www.glu.org/en/node/199 |access-date= 7 February 2009 |url-status= dead |archive-url= https://web.archive.org/web/20090429205753/http://www.glu.org/en/node/199 |archive-date= 29 April 2009 }}</ref>
Various parasites and predators of ''R. obtusifolius'' include 32 insect species and 12 fungi species.<ref name=cabi/> In the UK, the invertebrate herbivore species is a leaf beetle, ''Gastrophysa viridula''.<ref name=cabi/>
==References== {{Reflist}}
==External links== {{Commons|Rumex obtusifolius}} * {{PFAF|Rumex obtusifolius}} * {{Calflora}} * {{CalPhotos|Rumex|obtusifolius}}
{{Taxonbar|from=Q162800}}
obtusifolius Category:Flora of Europe Category:Plants described in 1753 Category:Botanical taxa named by Carl Linnaeus