plumeless thistle

(Carduus acanthoides)

               
Conservation Status

IUCN Red List

not yet assessed

plumeless thistle

NatureServe

NNA - Not applicable

SNA - Not applicable

Minnesota

not listed

Weed Status

SN – State noxious weed

PS – State prohibited weed seed

Nativity

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

Occurrence

 

Habitat

Pastures, disturbed areas, roadsides.

Flowering

July to October

     
Flower Color

Purple

     
Height

12 to 60

     

Identification

This is a 12 to 60 tall, erect, biennial forb that rises on a single stem from a long, stout, fleshy taproot.

In the first year the plant appears as a dense rosette of basal leaves. In the second year it sends up a single flowering stem.

The stems are erect, ribbed, and freely branched near the top. They may be hairless or lightly covered with soft, long, unmatted 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.

Basal leaves are lance-shaped to elliptic in outline and 4 to 8 long. They are deeply lobed (pinnatifid). The lobes are irregular and also toothed or lobed. The ultimate lobes or teeth are tipped with relatively hard, straw-colored spines. The upper and lower surfaces are green and sometimes hairless, usually sparsely covered with long, soft, shaggy, unmatted hairs mostly along the main veins.

Stem leaves are similar, alternate, and stalkless, becoming smaller and less divided as they ascend the stem. The base of the leaf continues down the stem and forms a pair of spiny wings. Upper stem leaves are lance-shaped and unlobed.

The inflorescence is a usually a single flower head, sometimes a cluster of 2 to 5 flower heads, held erect at the end of the stem and each branch. The heads may be unstalked or at the end of a long, spiny-winged stalk.

The whorl of bracts at the base of the flower head (involucre) is to 1 in diameter and in the shape of half of a sphere. The bracts of the involucre are narrowly lance-shaped, erect or loosely spreading, and no more than 1 16 wide. The middle and outer bracts have long spines at the tip.

The flower heads are ½ to 1 wide. They have numerous purple, tubular flowers.

The fruit is a golden to brown, 1 16 to long achene with whitish, minutely barbed hairs attached.

 
Similar
Species

Musk thistle (Carduus nutans) is a larger plant. The basal leaves are longer, up to 16 long. The upper side of the leaf is hairless. The flower stalk is usually naked, not winged, but sometimes has a few small, scattered bracts. The flower head droops ninety degrees when mature. The flower heads are much larger, ¾ to 2¾ wide.


Distribution Distribution Map   Sources: 2, 3, 4, 5, 7, 22, 28.

Comments

 


Taxonomy

Family:

Asteraceae (aster)

 

Subfamily:

Carduoideae

 

Tribe:

Cynareae

 

Subtribe:

Carduinae

 
Synonyms

Carduus nutans var. leiophyllus

Carduus nutans var. vestitus

 
Common
Names

plumeless thistle

spiny plumeless thistle

spiny plumeless-thistle

welted thistle


 

 

 

 

 

 

 

 

Glossary

Bract

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

 

Glaucous

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

 

Involucre

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

 

Pinnatifid

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.

 

Sepal

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

 

Wing

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

       

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  plumeless thistle    
       

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  plumeless thistle   plumeless thistle
       
       

 

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Slideshows

   
  Carduus acanthoides
Matt Lavin
 
  Carduus acanthoides  
 
About

Introduced annual to biennial herb with stems upward of 1.5 m tall, the capillary bristles reveal that this is not a species of Cirsium, the many very slender flowering stems each with longitudinal spiny wings and bearing one-several flowering heads are distinctive of this species, common along roadsides, ditches, pastures, and other disturbed sites.

 
     

 

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Other Videos

 
  Plumeless Thistle, identification of the Wisconsin Invasive Species Carduus acanthoides
uwcoopextension
 
   
 
About

Uploaded on Jan 31, 2011

This is part of a series of videos providing key characteristics for the identification of invasive plants listed in Wisconsin's invasive species administrative rule NR 40. These videos are produced by Dr. Mark Renz of the University of Wisconsin-Madison. For more information on invasive plants and invasive plant management in Wisconsin visit http://fyi.uwex.edu/weedsci or http://ipcm.wisc.edu/Publications/WeedSciencepublications/tabid/116/Default.aspx

 
     
  Spiny Plumeless Thistle (Carduus Acanthoides) - 2012-06-25
W3stlander
 
   
 
About

Published on Jun 27, 2012

Carduus acanthoides is a species of thistle known as the spiny plumeless thistle and welted thistle.

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De langstekelige distel of veeldoornige distel (Carduus acanthoides) is een plant uit de composietenfamilie (Asteraceae).

 
     
  Weed Management: Thistles
TheHorseVideo
 
   
 
About

Uploaded on Mar 31, 2011

Dr. William Witt of the University of Kentucky discusses managing four thistles--musk, plumeless, bull, and Canada thistles--in horse pastures.

 
     

 

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