Cirsium Hallii

''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. 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.

They are mostly native to Eurasia and northern Africa, with about 60 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.

''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. 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. 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). 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''. 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. 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

383 species are accepted. Selected species include:

*''Cirsium acaule'' – dwarf thistle
*'' Cirsium altissimum'' – roadside thistle, tall thistle
*'' Cirsium andersonii'' – Anderson's thistle, rose thistle
*'' Cirsium andrewsii'' – Franciscan thistle
*'' Cirsium arisanense''
*'' Cirsium arizonicum'' – Arizona thistle
*''Cirsium arvense'' – creeping thistle, field thistle
**''Cirsium arvense'' var.''argenteum''
**''Cirsium arvense'' var. ''integrifolium''
**''Cirsium arvense'' var. ''mite''
**''Cirsium arvense'' var. ''vestitum''
*'' Cirsium barnebyi'' – Barneby's thistle
*'' Cirsium boninense''
*'' Cirsium brachycephalum''
*'' Cirsium brevifolium'' – Palouse thistle
*'' Cirsium brevistylum'' – clustered thistle
*'' Cirsium calcareum'' – Cainville thistle
*'' Cirsium canescens'' – Platte thistle, prairie thistle
*'' Cirsium canum'' – Queen Anne's thistle
*'' Cirsium carolinianum'' – Carolina thistle, soft thistle
*'' Cirsium centaureae''
*'' Cirsium chellyense'' – queen thistle
*'' Cirsium ciliolatum'' – ashland thistle
*'' Cirsium clavatum'' – lake thistle
*'' Cirsium clokeyi'' – Charleston Mountain thistle, whitespine thistle
*'' Cirsium congdonii'' – rosette thistle
*'' Cirsium crassicaule'' – slough thistle
*'' Cirsium creticum''
*'' Cirsium cymosum'' – peregrine thistle
*'' Cirsium discolor'' – field thistle, pasture thistle
*'' Cirsium dissectum'' – meadow thistle ( syn. ''Cirsium lanceolatum'' non )
*'' Cirsium douglasii''
*'' Cirsium drummondii'' – dwarf thistle
*'' Cirsium durangense''
*'' Cirsium eatonii'' – Eaton's thistle
*'' Cirsium edule'' – edible thistle
*'' Cirsium engelmannii'' – Engelmann thistle, Engelmann's thistle
*''Cirsium erisithales'' – yellow melancholy thistle
*'' Cirsium esculentum''
*'' Cirsium flodmanii'' – Flodman thistle, Flodman's thistle
*'' Cirsium foliosum'' – Drummond's thistle, elk thistle, leafy thistle, meadow thistle
*'' Cirsium fontinale'' – fountain thistle
*''Cirsium funkiae'' – funky thistle
*'' Cirsium grahamii'' – Graham's thistle
*'' Cirsium griseum'' – gray thistle
*'' Cirsium helenioides''
*''Cirsium heterophyllum'' – melancholy thistle
*'' Cirsium hookerianum'' – white thistle
*'' Cirsium horridulum'' – yellow thistle
*'' Cirsium hydrophilum'' – Suisun thistle
*'' Cirsium hypoleucum''
*'' Cirsium jaliscoense''
*'' Cirsium japonicum'' – Japanese thistle
*'' Cirsium kamtschaticum'' – Kamchatka thistle
*'' Cirsium lecontei'' – Le Conte's thistle
*'' Cirsium leo''
*'' Cirsium libanoticum''
*'' Cirsium loncholepis'' – LaGraciosa thistle
*'' Cirsium longistylum'' – longstyle thistle
*'' Cirsium maritimum''
*'' Cirsium mexicanum'' – Mexican thistle
*'' Cirsium mohavense'' – Mojave thistle
*'' Cirsium muticum'' – swamp thistle
*'' Cirsium neomexicanum'' – lavender thistle, New Mexico thistle, powderpuff thistle
*'' Cirsium nipponicum''
*'' Cirsium nuttallii'' – Nuttall's thistle
*'' Cirsium occidentale'' – cobweb thistle
*'' Cirsium ochrocentrum'' – yellowspine thistle
*'' Cirsium oleraceum'' – cabbage thistle
*'' Cirsium ownbeyi'' – Ownbey's thistle
*''Cirsium palustre'' – marsh thistle
*'' Cirsium parryi'' – Parry's thistle or Cloudcroft thistle
*'' Cirsium peckii'' – Steens Mountain thistle
*'' Cirsium pendulum''
*'' Cirsium perplexans'' – Rocky Mountain thistle
*'' Cirsium pitcheri'' – Pitcher's thistle, sand dune thistle
*'' Cirsium praeteriens'' – Palo Alto thistle, lost thistle
*'' Cirsium pulcherrimum'' – Wyoming thistle
*'' Cirsium pumilum'' – pasture thistle
** ''Cirsium pumilum'' var. ''hillii'' – Hill's thistle
**''Cirsium pumilum'' var. ''pumilum''
*'' Cirsium pyrenaicum''
*'' Cirsium quercetorum'' – Alameda County thistle
*'' Cirsium remotifolium'' – fewleaf thistle
**''Cirsium remotifolium'' var. ''odontolepis''
**''Cirsium remotifolium'' var. ''remotifolium'' – fewleaf thistle
**''Cirsium remotifolium'' var. ''rivulare''
*'' Cirsium repandum'' – sandhill thistle
*'' Cirsium rhaphilepis''
*'' Cirsium rhinoceros'' – Korean prickly thistle
*'' Cirsium rhothophilum'' – surf thistle
*'' Cirsium rivulare'' – brook thistle
*'' Cirsium rydbergii'' – Rydberg's thistle
*'' Cirsium scapanolepis'' – mountain slope thistle
*'' Cirsium scariosum'' – meadow thistle
*'' Cirsium scopulorum'' – mountain thistle
*'' Cirsium setidens'' – gondre or Korean thistle
*'' Cirsium spinosissimum''
*'' Cirsium texanum'' – Texas thistle
*'' Cirsium tioganum'' – stemless thistle
*†'' Cirsium toyoshimae''
*''Cirsium tuberosum'' – tuberous thistle
*'' Cirsium turneri'' – cliff thistle
*'' Cirsium undulatum'' – gray thistle, wavy-leaf thistle, wavyleaf thistle
**''Cirsium undulatum'' var. ''tracyi'' – Tracy's thistle, wavyleaf thistle
**''Cirsium undulatum'' var. ''undulatum'' – wavyleaf thistle
*'' Cirsium vinaceum'' – Sacramento Mountain thistle, Sacramento Mountains thistle
*''Cirsium virginianum'' – Virginia thistle
*''Cirsium vulgare'' – spear thistle, common thistle ( syn. ''Cirsium lanceolatum'' )
*'' Cirsium wheeleri'' – Wheeler's thistle
*'' Cirsium wrightii'' – Wright's thistle

;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'' (as ''Cirsium buchwaldii'' )
*'' Afrocirsium schimperi'' (as ''Cirsium schimperi'' )
*'' Afrocirsium straminispinum'' (''Cirsium straminispinum'' )
*'' Epitrachys italica'' (as ''Cirsium italicum'' )
*'' Lophiolepis eriophora'' (as '' Cirsium eriophorum'' ) – woolly thistle
*'' Nuriaea dender'' (as ''Cirsium dender'' )
*'' Nuriaea engleriana'' (as ''Cirsium englerianum'' )
*'' Picnomon acarna'' (as ''Cirsium acarna'' ) – soldier thistle

Image gallery

References

Further reading

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{{Authority control

Asteraceae genera
Taxa named by Philip Miller