''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.''Carduus''.
Integrated Taxonomic Information System (ITIS).''Carduus''.
Flora of North America. They are native to Eurasia and Africa, and several are known elsewhere as introduced species. This genus is noted for its disproportionately high number of

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

s compared to other flowering plant genera.

Etymology

The genus name ''Carduus'' is from the Latin for "a kind of thistle"''Carduus''.
The Jepson eFlora 2013. or "thistlelike plant". It is related to the word ''Cardonnacum'' ("a place of chardons or thistles"), which is the origin of

Chardonnay Chardonnay (, , ) is a green-skinned grape variety used in the production of white wine. The variety originated in the Burgundy wine region of eastern French wine, France, but is now grown wherever wine is produced, from English wine, Englan ...

, the name of the grape variety. It is also related to the word ''card'', which as a noun means a device (often a stiff-bristled brush) for aligning and cleaning fibers, and as a verb means the action of processing fibers in that way.

Description

These are usually annual or biennial herbs, sometimes perennial. Species often grow 2 meters in height but are known to reach 4 meters. The erect stems are winged and spiny, and usually have woolly hairs. The leaf blades are hairy to hairless and entire or divided into lobes, and they have spine-toothed edges. The

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

are solitary or borne in inflorescences of up to 20. The head is spherical to cylindrical and covered in several layers of spreading or curving spine-tipped phyllaries. It contains long, tubular disc florets in shades of white, pink, or purple. The fruit is a cypsela tipped with a pappus of barbed bristles or scales.

Ecology

Several ''Carduus'' are notorious invasive plants outside their native range, for example, in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and the United States.Genus ''Carduus''.
Encycloweedia. California Department of Food and Agriculture. Species such as ''C. acanthoides'', ''C. nutans'', ''C. pycnocephalus'', and ''C. tenuiflorus'' easily become weedy in disturbed habitat, such as

overgrazed Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature rese ...

pasture. ''C. nutans'' is

allelopathic Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have ben ...

, producing compounds that inhibit the growth and development of other plants. Agents of

biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

that have been used against weedy ''Carduus'' thistles include the thistle head weevil (''Rhinocyllus conicus''), thistle crown weevil (''Trichosirocalus horridus''), and thistle crown fly (''Cheilosia corydon''). The musk thistle rust (''Puccinia carduorum''), a fungus, may also be used against ''C. nutans''.

Diversity

File:20130413Carduus acanthoides1.jpg, '' Carduus acanthoides'' File:Partially opened flower bud of Carduus nutans.jpg, ''

Carduus nutans ''Carduus nutans'', with the common names musk thistle, nodding thistle, and nodding plumeless thistle, is a biennial plant in the daisy and sunflower family Asteraceae. It is native to regions of Eurasia. Description ''Carduus nutans'' is usual ...

'' File:1398 - Nationalpark Hohe Tauern - Flowers.JPG, ''

Carduus personata ''Carduus personata'' is a perennial herbaceous plant in the family Asteraceae. Etymology The genus name ''Carduus'' is the classical Latin name for "thistle", also the species name (''personata'') derives from Latin ("personatus" = masked) ...

'' File:Carduus Keniensis.jpg, ''

Carduus keniensis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' There are about 90 to 127''Carduus''.
The Plant List. species in the genus. Species include: *''

Carduus acanthocephalus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *'' Carduus acanthoides'' – spiny plumeless thistle *''

Carduus acicularis ''Carduus argentatus'', sometimes known as the silver thistle, is an annual herb in the family Asteraceae. As a member of the genus ''Carduus'' it is known as a plumeless thistle.Carduus adpressus'' *''

Carduus affinis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus afromontanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus amanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus angusticeps ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus arabicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus argentatus ''Carduus argentatus'', sometimes known as the silver thistle, is an annual herb in the family Asteraceae. As a member of the genus ''Carduus'' it is known as a plumeless thistle.Carduus argyroa ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus asturicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus aurosicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus axillaris ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus baeocephalus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus ballii ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus bourgaei ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus bourgeanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus broteroi ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus budaianus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus candicans ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus carduelis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus carlinoides ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus carpetanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus cephalanthus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus chevallieri ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus chrysacanthus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus clavulatus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus corymbosus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus collinus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *'' Carduus crispus'' – curly plumeless thistle, curled thistle, welted thistle *''

Carduus dahuricus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus defloratus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus edelbergii ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus euboicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus fallax ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus fasciculiflorus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus fissurae ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus getulus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus hamulosus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus hazslinszkyanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus hohenackeri ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus ibicensis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus jordanii ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus juratzkae ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus kerneri ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus kirghisicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus knorringianus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus kumaunensis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus lanuginosus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus leptacanthus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus leptocladus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus litigiosus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *'' Carduus lobulatus'' *''

Carduus lusitanicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus macracanthus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus macrocephalus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus malyi ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus maroccanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus martinezii ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus membranaceus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus meonanthus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus millefolius ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus modestii ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus myriacanthus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus nervosus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus nigrescens ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

'' – musk thistle, nodding thistle *''

Carduus olympicus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

'' *'' Carduus pycnocephalus'' – Italian thistle, Italian plumeless thistle, compact-headed thistle *''

Carduus ramosissimus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus schimperi ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' (may include ''C. platyphyllus'' and ''C. chamaecephalus'') *''

Carduus tenuiflorus ''Carduus tenuiflorus'', known variously as slender-flower thistle, sheep thistle, shore thistle, slender thistle, winged plumeless thistle, winged slender thistle and winged thistle, is a species of flowering plant in the family Asteraceae. It ...

'' – sheep thistle, shore thistle, slender thistle *''

Carduus textorisianus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' Marg. *''

Carduus uncinatus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus weizensis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' ;Hybrids *''

Carduus × aragonensis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus × arvaticus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus × camplonensis ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus × cantabricus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus × cyrneus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''

Carduus × ipe ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being '' Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *''Carduus keniensis'' × ''C. platyphyllus''Young, T. P. and M. M. Peacock. (1985)
Vegetative key to the alpine vascular plants of Mount Kenya.
''Journal of the East African Natural History Society'' 185, 1–9. *''

Carduus × leridanus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' *'' Carduus'' × ''orthocephalus''

References

External links

*
''Carduus''.
In: Greuter, W. & E. von Raab-Straube. (Eds.) Compositae. Euro+Med Plantbase. 2006.

BioImages: The Virtual Field-Guide (UK). Accessed 2013-02-17. {{Taxonbar, from=Q254502 Asteraceae genera Butterfly food plants Taxa named by Carl Linnaeus