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Cirsium

{{Short description|Genus of flowering plants in the daisy family Asteraceae}}

{{Automatic taxobox

|image = Cirsium heterophyllum 5 RF.jpg

|image_caption = Cirsium heterophyllum (melancholy thistle)

|display_parents = 3

|taxon = Cirsium

|authority = Mill.

|subdivision_ranks = Species

|subdivision = 383; see text

|subdivision_ref = [https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30001899-2 Cirsium Mill.]. Plants of the World Online. Retrieved 2 June 2024.

|synonyms =

  • Ancanthia {{small|Steud. (1840), not validly publ.}}
  • Ascalea {{small|Hill (1762)}}
  • Breea Less. (1832)
  • Cephalanophlos Neck. (1790), not validly publ.
  • Cephalonoplos (Neck. ex DC.) Fourr. (1869), nom. superfl.
  • Echenais Cass. (1818)
  • Eriolepis Cass. (1826)
  • Erythrolaena Sweet (1825)
  • Ixine {{small|Hill (1762)}}
  • Onopix {{small|Raf. (1817)}}
  • Onotrophe Cass.
  • Spanioptilon {{small|Less. (1832)}}
  • Tetralix {{small|Hill (1762), nom. illeg.}}
  • Xylanthema {{small|Neck. (1790)}}

|synonyms_ref =

}}

Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more precisely known as plume thistles{{citation needed|date=June 2024}}. These differ from other thistle genera (Carduus, Silybum and Onopordum) in having a seed with a pappus of feathered hairs on their achenes. The other genera have a pappus of simple unbranched hairs.{{cite book |last=Rose |first=Francis|author-link=Francis Rose |title=The Wild Flower Key |year=1981 |publisher=Frederick Warne & Co |isbn=0-7232-2419-6 |pages=377–380}}

They are mostly native to Eurasia and northern Africa, with about 60{{cite web |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=107139 |work=Flora of North America |title=Cirsium}} species from North America (although several species have been introduced outside their native ranges). The lectotype species of the genus is Cirsium heterophyllum (L.) Hill.International Plant Names Index: [https://www.ipni.org/n/30001899-2 Cirsium]

Cirsium thistles are known for their effusive flower heads, usually purple, rose or pink, also yellow or white. The radially symmetrical disc flowers are at the end of the branches and are visited by many kinds of insects, featuring a generalised pollination syndrome.{{Cite journal |doi=10.1111/plb.12328 |title=Competition for pollinators and intra-communal spectral dissimilarity of flowers |journal=Plant Biology |pages=56–62 |year=2015 |last1=Van Der Kooi |first1=C. J. |last2=Pen |first2=I. |last3=Staal |first3=M. |last4=Stavenga |first4=D. G. |last5=Elzenga |first5=J. T. M. |url=https://www.researchgate.net/publication/273158762 |pmid=25754608 |volume=18 |issue=1}} They have erect stems, with a characteristic enlarged base of the flower which is often spiny. The leaves are alternate, spiny in many (but not all) species, and in some species can be slightly to densely hairy. Extensions from the leaf base down the stem, called wings, can be lacking (Cirsium arvense), conspicuous (Cirsium vulgare), or inconspicuous. They can spread by seed, and also by rhizomes below the surface (Cirsium arvense). The seeds have a tuft of hair, or pappus, which can carry them far by wind.

Cirsium thistles are used as food plants by the larvae of some Lepidoptera species—see list of Lepidoptera that feed on Cirsium. The seeds are attractive to small finches such as American goldfinch.

Many species are considered weeds, typically by agricultural interests. Cirsium vulgare (spear thistle) is listed in the United States (where as a non-native invasive species it has been renamed "bull thistle") as a noxious weed in nine states.{{cite web |url=http://plants.usda.gov/java/profile?symbol=CIVU |title=PLANTS Profile for Cirsium vulgare (bull thistle) USDA PLANTS |access-date=2008-07-15 |work=USDA Plant Database |publisher=USDA}} Some species in particular are cultivated in gardens and wildflower plantings for their aesthetic value and/or to support pollinators such as bees and butterflies. Some species dubbed weeds by various interest groups can also provide these benefits. Cirsium vulgare, for instance, ranked in the top 10 for nectar production in a UK plants survey conducted by the AgriLand project which is supported by the UK Insect Pollinators Initiative. Cirsium vulgare was also a top producer of nectar sugar in another study in Britain, ranked third with a production per floral unit of (2323 ± 418μg).{{cite journal |last1=Hicks |first1=DM |last2=Ouvrard |first2=P |last3=Baldock |first3=KCR |title=Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows |journal=PLOS ONE |volume=11 |issue=6 |date=2016 |doi=10.1371/journal.pone.0158117 |pmc=4920406 |pmid=27341588 |page=e0158117 |bibcode=2016PLoSO..1158117H |doi-access=free}} Not only does it provide abundant nectar, it provides seeds for birds, such as the European goldfinch Carduelis carduelis, and supports the larvae of the Painted Lady butterfly Vanessa cardui.{{cite web |title=Which flowers are the best source of nectar? |publisher=Conservation Grade |url=http://www.conservationgrade.org/2014/10/which_flowers_best_source_nectar/ |access-date=2017-10-18 |date=2014-10-15 |archive-date=2019-12-14 |archive-url=https://web.archive.org/web/20191214024659/http://www.conservationgrade.org/2014/10/which_flowers_best_source_nectar/ |url-status=dead}} Some other common species are Cirsium arvense, Cirsium palustre, Cirsium oleraceum.

Some ecological organizations, such as the Xerces Society, have attempted to raise awareness of the benefits of thistles, to counteract the general agricultural and home garden labeling of thistles as unwanted weeds. The monarch butterfly (Danaus plexippus), for instance, was highlighted as relying upon thistles such as tall thistle (Cirsium altissimum) as nectar sources during its migration.{{cite web |url=https://xerces.org/native-thistle-guide/ |title=Native Thistles: A Conservation Practitioner's Guide |last1=Eckberg |first1=James |last2=Lee-Mäder |first2=Eric |last3=Hopwood |first3=Jennifer |last4=Foltz Jordan |first4=Sarah |last5=Borders |first5=Brianna |date=2017 |website=The Xerces Society |access-date=27 August 2018}} Some prairie and wildflower seed production companies in the United States supply bulk seed of native North American thistle species for wildlife habitat restoration, although availability tends to be low. Thistles are particularly valued by bumblebees for their high nectar production.

Certain species of Cirsium, like Cirsium monspessulanum, Cirsium pyrenaicum and Cirsium vulgare, have been traditionally used as food in rural areas of southern Europe. Cirsium oleraceum is cultivated as a food source in Japan and India. Cirsium setidens is used as a vegetable in Korean cuisine.

'Cirsium' is the Greek word for thistle, kirsos, likely derived from 'swollen vein'. The flower blooms April to August.

Selected species

{{Main|List of Cirsium species|l1=List of Cirsium species}}

383 species are accepted. Selected species include:

{{div col|colwidth=300px}}

{{div col end}}

;Hybrids

  • Cirsium × canalense – canal thistle
  • Cirsium × crassum – thistle
  • Cirsium × erosum – glory thistle
  • Cirsium × iowense – Iowa thistle
  • Cirsium × vancouverense – Vancouver thistle

=Formerly placed here=

  • Afrocirsium buchwaldii {{small|(O.Hoffm.) Calleja, N.Garcia, Moreyra & Susanna}} (as Cirsium buchwaldii {{small|O.Hoffm.}})
  • Afrocirsium schimperi {{small|(Vatke) Calleja, N.Garcia, Moreyra & Susanna}} (as Cirsium schimperi {{small|(Vatke) C.Jeffrey}})
  • Afrocirsium straminispinum {{small|(C.Jeffrey) Calleja, N.Garcia, Moreyra & Susanna}} (Cirsium straminispinum {{small|C.Jeffrey}})
  • Epitrachys italica {{small|(DC.) Bureš, Del Guacchio, Iamonico & P.Caputo}} (as Cirsium italicum {{small|DC.}})
  • Lophiolepis eriophora {{small|(L.) Del Guacchio, Bureš, Iamonico & P.Caputo}} (as Cirsium eriophorum {{small|(L.) Scop.}}) – woolly thistle
  • Nuriaea dender {{small|(Friis) Susanna, Calleja & Moreyra}} (as Cirsium dender {{small|Friis}})
  • Nuriaea engleriana {{small|(O.Hoffm.) Susanna, Calleja & Moreyra}} (as Cirsium englerianum {{small|O.Hoffm.}})
  • Picnomon acarna {{small|(L.) Cass.}} (as Cirsium acarna {{small|(L.) Moench}}) – soldier thistle

Image gallery

{{gallery

|File:European Goldfinch on Spear Thistle.jpg|A European Goldfinch eating seeds on a Cirsium vulgare (spear thistle) seedhead

|File:Red Thistle 1.JPG|Cirsium arizonicum (Arizona thistle)

|File:Cirsium canum0.jpg|Cirsium canum (Queen Anne's thistle)

|File:Honeybee thistle.jpg|Bumblebee on a Cirsium arvense (creeping thistle) flowerhead

|File:Spear Thistle (Cirsium vulgare) (4752364908).jpg|Cirsium vulgare (spear thistle)

|File:Cirsium spinosissimum RF.jpg|Cirsium spinosissimum (spiniest thistle)

|File:Cardos.JPG|Cirsium pyrenaicum cut and ready to cook

|File:Texas_Purple_Thistle.jpg|Texas purple thistle

}}

References

{{Reflist|2}}

Further reading

{{Refbegin}}

  • {{Cite book |last1=Everitt |first1=J.H. |last2=Lonard |first2=R.L. |last3=Little |first3=C.R. |title=Weeds in South Texas and Northern Mexico |publisher=Texas Tech University Press |location=Lubbock |year=2007}} {{ISBN|0-89672-614-2}}

{{Refend}}

  • {{Commons category-inline|Cirsium}}

{{Taxonbar|from=Q1638558}}

{{Authority control}}

Category:Asteraceae genera

Category:Taxa named by Philip Miller