musk thistle

(Carduus nutans ssp. macrocephalus)

Conservation Status
musk thistle (ssp. macrocephalus)
  IUCN Red List

not listed


NNA - Not applicable

SNA - Not applicable


not listed

Weed Status

Prohibited Weed Seed

County Noxious Weed in Clay, Lincoln, and Yellow Medicine Counties

Musk thistle is listed as an invasive terrestrial plant by the Minnesota Department of Natural Resources.

Musk thistle was formerly listed by the Minnesota Department of Agriculture as a State Noxious Weed. In 2013 the Noxious Weed Advisory Committee recommended removing it from the list for several reasons, including: it does not pose a significant threat to agricultural production or native ecosystems; it is easily controlled; and it is so widespread that there is no meaningful chance of its eradication.

Wetland Indicator Status
  Great Plains

FACU - Facultative upland


FACU - Facultative upland

  Northcentral & Northeast

FACU - Facultative upland


Musk thistle (subspecies macrocephalus) is a 16 to 78 tall, erect, biennial forb that rises on a single stem from a stout taproot.

The stems are erect, ribbed, and often branched near the top. They may be hairless or covered with short, soft, woolly, matted or tangled hairs. They have small appendages (wings) running the length of the stem and branches except just below the inflorescence. The wings are interrupted, not continuous for the length of the stem. They are irregularly lobed and wavy, each lobe tipped with relatively hard, straw-colored spines.

In the first year the plant appears as a rosette of basal leaves that may be 24 or more in diameter. In the second year it sends up a single flowering stem.

Basal leaves are lance-shaped to broadly elliptic in outline and 4 to 16 long. In the first year they are shallowly lobed, sometimes with a whitish, waxy bloom (glaucous), and irregularly prickled. In the second year they become deeply lobed (pinnatifid), each lobe again lobed (bipinnatifid). The primary lobes are cut up to 80% of the way to the midrib. The ultimate lobes are triangular-shaped and tipped with relatively hard, straw-colored spines. The upper side is dark green and moderately hairy with a light green midrib. The underside is moderately hairy. The margins are often whitish.

Stem leaves are similar, alternate, stalkless, and up to 12 long, becoming smaller and less divided as they ascend the stem. The ultimate lobes are lance-shaped to egg-shaped. The base of the leaf continues down the stem and forms a pair of spiny wings. Upper stem leaves are lance-shaped and ½ to 6 long.

The inflorescence is a usually a single, short-stalked flower head at the end of the stem and each branch, sometimes a cluster of a few flower heads. The flower stalk is relatively naked—leafless and not winged—but sometimes has a few small, scattered bracts. It is often densely covered with felty hairs. The flower head nods (droops) ninety degrees when mature.

The whorl of bracts at the base of the flower head (involucre) is cup-shaped to somewhat bell-shaped, ¾ to 2 long, and ¾ to 2¾ wide. The bracts of the involucre (phyllaries) are lance-shaped to egg-shaped, spreading to bent backward, to 2 long, 1 16 to ¼ wide, and sometimes purple at the tip. They are abruptly tapered to a 1 32 to long spine at the tip. They are covered with cobwebby hairs.

The flower heads are ¾ to 2¾ wide. They have numerous purplish to white tubular flowers.

The fruit is a golden to brown, to 3 16 long achene with whitish, barbed hairs attached.




16 to 78


Flower Color


Purple to white


Similar Species


Musk thistle (Carduus nutans ssp. leiophyllus) upper leaf surface is hairless. The lower leaf surface is hairless except for sometimes some hairs along the main veins. The flower stalks are long.

Musk thistle (Carduus nutans ssp. macrolepis) involucral bracts are evenly tapered, not abruptly tapered, at the tip. The upper leaf surface is hairless. The lower leaf surface is hairless except for sometimes some hairs along the main veins. The flower stalks are long.


Disturbed areas, roadsides.




June to October


Pests and Diseases






Distribution Map







Native of Asia and Europe. Introduced and naturalized in North America.

Up to 20 subspecies and varieties of Carduus nutans are currently recognized. It is likely that more than one of these have been introduced and are now naturalized in North America. Where more than one of these occurs in the same area they cross pollinate, producing plants with intermediate characteristics that cannot always be reliably assigned.





  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Asterales (sunflowers, bellflowers, fanflowers, and allies)  


Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Carduoideae (thistles and allies)  
  Tribe Cardueae  
  Subtribe Carduinae (thistles and burdocks)  
  Genus Carduus (plumeless thistles)  
  Species Carduus nutans (musk thistle)  

Cardueae is a synonym of the tribe name. Cynareae was published first and has precedence. Nevertheless, most sources use the name Cardueae for the tribe.


Subordinate Taxa






Carduus macrocephalus

Carduus nutans var. macrocephalus


Common Names


musk thistle

nodding plumeless thistle

nodding plumeless-thistle

nodding thistle

plumeless thistle




















Twice pinnatifid. Cut deeply into lobes with each lobe also cut into deep lobes.



Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.



Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.



A whorl of bracts beneath or surrounding a flower or flower cluster.



An individual bract within the involucre of a plant in the Asteraceae family.



Deeply cut, more than half way to the midrib but not to the midrib, into lobes that are spaced out along the midrib; the lobes do not form separate leaflets.



An outer floral leaf, usually green but sometimes colored, at the base of a flower.



A thin, flat, membranous, usually transparent appendage on the margin of a structure.

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    musk thistle (ssp. macrocephalus)   musk thistle (ssp. macrocephalus)  

Flower Head

    musk thistle (ssp. macrocephalus)   musk thistle (ssp. macrocephalus)  

Short Flower Stalk

    musk thistle (ssp. macrocephalus)      


    musk thistle (ssp. macrocephalus)   musk thistle (ssp. macrocephalus)  


    musk thistle (ssp. macrocephalus)      






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