''Carduus'' is a genus of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

, and the tribe

Cardueae The Cardueae are a tribe (biology), tribe of flowering plants in the daisy family (Asteraceae) and the subfamily Carduoideae. Most of them are commonly known as thistles; four of the best known genera are ''Carduus'', ''Cynara'' (containing the ...

, one of two genera considered to be true thistles, the other being ''

Cirsium ''Cirsium'' is a genus of Perennial plant, perennial and Biennial plant, 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 thist ...

''. 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 temperate Eurasia and North Africa, and several are known elsewhere as

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

. 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 harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or lives ...

s compared to other flowering plant genera.

Etymology

The genus name ''Carduus'' is from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

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 France, but is now grown wherever wine is produced, from England to New Zealand. For new a ...

, the name of the

grape variety This list of grape varieties includes cultivated grapes, whether used for wine, or eating as a table grape, fresh or dried (raisin, Zante currant, currant, sultana (grape), sultana). For a complete list of all grape species, including those unimp ...

. 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 (; : pseudanthia) 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, composite flowers ...

are solitary or borne in

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s of up to 20. The head is spherical to cylindrical and covered in several layers of spreading or curving spine-tipped

phyllaries In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract of the involucre of a composite flower. The involucre is the grouping of bracts together. Phyllaries are reduced leaf-like structures that form one o ...

. 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 An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native species ...

outside their native range, for example, in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

.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 r ...

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, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or ot ...

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 A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

, may also be used against ''C. nutans''.

Species

File:20130413Carduus acanthoides1.jpg, ''

Carduus acanthoides ''Carduus acanthoides'', known as the spiny plumeless thistle, welted thistle, or plumeless thistle, is a biennial plant species of thistle in the family Asteraceae. The plant is native to Europe and Asia and introduced in many other areas, where ...

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

Carduus nutans ''Carduus nutans'' is a biennial plant in the daisy and sunflower family Asteraceae with the common names musk thistle, nodding thistle, and nodding plumeless thistle. It is native to regions of Europe, Central Asia, and North Africa, where it is ...

'' 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 language, Latin ("persona ...

'' The genus includes 82 accepted species, and several natural hybrids. *'' Carduus acanthocephalus'' *''

'' – spiny plumeless thistle *'' Carduus acicularis'' *'' Carduus adpressus'' *'' Carduus affinis'' *'' Carduus amanus'' *'' Carduus angusticeps'' *''

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 argentatus'' *'' Carduus argyroa'' *''

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 asturicus'' *''

Carduus × atacinus ''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 baeocephalus'' *''

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 × bergadensis'' *'' Carduus bourgaei'' *'' Carduus bourgeanus'' *''

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 × brunneri'' *'' Carduus budaianus'' *'' Carduus × camplonensis'' *'' Carduus candicans'' *'' Carduus × cantabricus'' *'' Carduus carduelis'' *'' Carduus carlinoides'' *'' Carduus carpetanus'' *'' Carduus cephalanthus'' *'' Carduus chevallieri'' *'' Carduus chrysacanthus'' *'' Carduus clavulatus'' *'' Carduus collinus'' *'' Carduus corymbosus'' *''

Carduus crispus ''Carduus crispus'', the curly plumeless thistle or welted thistle, is a Biennial plant, biennial herb in the daisy family Asteraceae. It is native to Eurasia and has been naturalized in North America and India. Description ''Carduus crispus'' ...

'' – curly plumeless thistle, curled thistle, welted thistle *'' Carduus dahuricus'' *'' Carduus defloratus'' *'' Carduus edelbergii'' *'' Carduus × estivali'' *''

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 fissurae'' *'' Carduus getulus'' *'' Carduus × gillotii'' *''

Carduus × grassensis ''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 × grenieri ''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 hazslinszkyanus'' *'' Carduus hohenackeri'' *'' Carduus ibicensis'' *''

Carduus × intercedens ''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 × 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 kerneri'' *'' Carduus kirghisicus'' *'' Carduus kumaunensis'' *'' Carduus lanuginosus'' *'' Carduus × leptocephalus'' *''

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 lobulatus'' *'' Carduus lusitanicus'' *'' Carduus macrocephalus'' *'' Carduus malyi'' *'' Carduus maroccanus'' *''

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 meonanthus'' *'' Carduus × meratii'' *''

Carduus × mixtus ''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 × montis-majoris'' *''

Carduus × moritzii ''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 nawaschini ''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 numidicus'' *''

'' – 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 onopordioides ''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'' *''

Carduus peisonis ''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 poliochrus'' *''

Carduus × puechii ''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 pumilus ''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 × pycnocephaloformis'' *''

Carduus pycnocephalus ''Carduus pycnocephalus'', with common names including Italian thistle, Italian plumeless thistle, and Plymouth thistle, is a species of thistle. It is native to the Mediterranean region in southern Europe, North Africa, and Western Asia; Easter ...

'' – Italian thistle, Italian plumeless thistle, compact-headed thistle ** ''Carduus pycnocephalus'' subsp. ''albidus'' ** ''Carduus pycnocephalus'' subsp. ''arabicus'' (synonym ''

Carduus arabicus ''Carduus arabicus'', known as the Arabian thistle, is a biennial plant species of thistle in the family Asteraceae. Habitat Grows in Europe (Albania, Greece, Italy ncl. h. Sicily Ukraine (Crimea), North Caucasus), Asia (Afghanistan, Gulf co ...

'' ) – Arabian thistle ** ''Carduus pycnocephalus'' subsp. ''breviphyllarius'' ** ''Carduus pycnocephalus'' subsp. ''cinereus'' ** ''Carduus pycnocephalus'' subsp. ''intermedius'' ** ''Carduus pycnocephalus'' subsp. ''pycnocephalus'' *''

Carduus quercifolius ''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 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 rechingerianus ''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 rivasgodayanus'' *''

Carduus santacreui ''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 × schulzeanus ''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 seminudus ''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 × sepincola'' *'' Carduus × septentrionalis'' *''

Carduus solteszii ''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 spachianus ''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 squarrosus'' *'' Carduus × stangii'' *'' Carduus tenuiflorus'' – sheep thistle, shore thistle, slender thistle *'' Carduus × theriotii'' *''

Carduus thracicus ''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 tmoleus'' *'' Carduus transcaspicus'' *'' Carduus × turocensis'' *'' Carduus uncinatus'' *'' Carduus × veronensis'' *''

Carduus × vigoi ''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 volutarioides ''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.

Formerly placed here

*''

Afrocarduus afromontanus ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus afromontanus'' ) *''

Afrocarduus keniensis ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus keniensis'' ) *''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. *''

Afrocarduus kikuyorum ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus kikuyorum'' ) *''

Afrocarduus leptacanthus ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus leptacanthus'' ) *''

Afrocarduus macracanthus ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus macracanthus'' ) *''

Afrocarduus millefolius ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus millefolius'' ) *''

Afrocarduus nyassanus ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus nyassanus'' ) *''

Afrocarduus ruwenzoriensis ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus ruwenzoriensis'' ) *''

Afrocarduus schimperi ''Afrocarduus'' is a genus of flowering plants in the sunflower family, Asteraceae. It includes ten species of thistles native to the mountains of tropical Africa, ranging from Nigeria to Ethiopia and Zimbabwe. All the species in the genus are n ...

'' (as ''Carduus schimperi'' ) *'' Afrocarduus silvarum'' (as ''Carduus silvarum'' )

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. {{Authority control Asteraceae genera Butterfly food plants Taxa named by Carl Linnaeus Flora of the Palearctic realm