bull thistle

(Cirsium vulgare)

               
Conservation Status

IUCN Red List

not yet assessed

bull thistle

NatureServe

NNA - Not applicable

SNA - Not applicable

Minnesota

not listed

Wetland
Indicator
Status

Great Plains

UPL - Obligate upland

Midwest

FACU - Facultative upland

Northcentral & Northeast

FACU - Facultative upland

Weed Status

PS – State prohibited weed seed

Invasive

Nativity

Native of Northern Africa, Asia, and Europe. Introduced in the United States; naturalized.

Occurrence

Common and widespread

 
Habitat

Moist to dry. Prairies, pastures, abandoned fields, forest openings, roadsides, railroads, disturbed sites. Full sun.

 
Flowering

Late June to August

 
Flower Color

Purple

 
Height

16 to 78

 

Identification

This is a 16 to 78 tall, erect, biennial forb that rises from a taproot and fibrous roots. The taproot is fleshy, thick, up to 28 deep, and often branched.

In its first year the plant produces a radiating cluster of leaves (rosette) above ground and a large taproot below ground. In the second year it sends up a single erect flowering stem, sometimes also one or more ascending side stems. The plant dies after flowering and setting seeds one time. It does not spread vegetatively. The seeds germinate easily but do not often survive. As a result plants are usually found singly or scattered.

The stem is stout, usually well branched, and light green with dark purple veins. It is sparsely to densely covered with long, soft, spreading hairs, at least the middle and upper sections. The upper portion of the stem is conspicuously winged. The sap is clear, not white.

The rosette of basal leaves produced in the first year is flat and can be 24 or more in diameter. The leaves are narrowly elliptic to inversely lance-shaped in outline, 6 to 16 long, and 1¼ to 6 wide. They are deeply cut into 4 to 6 widely spaced pairs of lobes (pinnatifid) with the lobes further cut into 3 or 4 smaller lobes (bipinnatifid). The ultimate lobes are rigid, triangular to lance-shaped, and tipped with a stout, yellowish, 1 16 to long spine. They extend both horizontally and vertically from the plane of the leaf blade and are mostly twisted at the base to face toward the leaf tip, giving the leaf a distinct three-dimensional appearance. The upper surface is dark green with a light green midrib. It is covered with short, straight, white hairs and small yellowish spines. The lower surface is lighter green and is covered with grayish, cobwebby hairs, at least along the veins. The leaves are densely hairy when young and become less hairy as they mature. The margins are spiny.

Stem leaves are 1¼ to 6 long; stalkless and slightly clasping; and deeply lobed, cut more than half way to the midrib. The lobes are narrow, often linear lance-shaped. The upper surface is covered with stiff, bristly hairs, at least along the veins. Stem leaves are otherwise similar to basal leaves. The blade of the leaf continues down the stem from the point of attachment as a wing that is up to wide. The margins of the wings are armed with spines up to ¼ long. The wing extends uninterrupted nearly to the leaf below. Middle stem leaves are often more deeply divided than lower leaves. The leaves become progressively smaller but no less divided as they ascend the stem. However, some of the uppermost leaves may be lance-shaped or linear and not divided.

The inflorescence is usually a single large flower head, sometimes a loose, branched, cluster (corymb) of 2 to a few large flower heads, at the end of the stem and each branch. The flower heads are stalkless or are borne singly on to 2 long stalks. The flower heads are subtended by one to several straight, unlobed, linear, spine-tipped, bract-like leaves.

At the base of each flower head there are 5 to 12 rows of numerous bracts (phyllaries) forming a hemispheric or bell-shaped base (involucre). The involucre is 1¼ to 1½ long and ¾ to 1½ wide, slightly longer than wide. It is loosely covered with cobwebby hairs, at least near the base. The lower and middle phyllaries are linear lance-shaped, curve outwards, and are long tapered to a spiny, straw-colored, 1 16 to 3 16long tip. The inner phyllaries are linear.

The flower heads are to 1½ to 2 in diameter. They have numerous tubular, 1 to 1 long disk florets. The disk florets are reddish-purple or purple, rarely white.

The fruit is a to 3 16 long seed capsule (cypsela). The cypsela is light brown and sometimes has dark longitudinal streaks. The collar near the tip is inconspicuous. There is a tuft of white or light tan hairs at the tip.

 
Similar
Species

 


Distribution Distribution Map   Sources: 2, 3, 4, 5, 7, 22, 24, 28.

Comments

First Appearance
The exact date and location of this species’ introduction is not known. It is thought to have been introduced into North America by European settlers, possibly as a seed contaminant, in the early 1800s.

Ecological Threat
Bull thistle is a prohibited weed seed in Minnesota but it is not considered as serious a threat as other invasive thistles. The spiny foliage makes it unpalatable to wildlife and livestock. It reproduces by seed only, not vegetatively. About 95% of the seeds germinate but few plants survive to maturity. Seeds that do not germinate in the first spring do not survive the following winter unless they are buried. Seeds that are buried at least 5 inches, as in cropland under cultivation, remain viable for only 3 years.


Taxonomy

Family:

Asteraceae (aster)

 

Subfamily:

Carduoideae

 

Tribe:

Cynareae

 

Subtribe:

Carduinae

 
Synonyms

Carduus lanceolatus

Carduus vulgaris

Cirsium lanceolatum

Cirsium lanceolatum var. hypoleucum

 
Common
Names

bull thistle

common thistle

spear thistle


 

 

 

 

 

 

 

 

 

 

 

Glossary

bipinnatifid

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

 

bract

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

 

clasping

Describing a leaf that wholly or partly surrounds the stem but does not fuse at the base.

 

corymb

A flat-topped or convex inflorescence in which the stalked flowers grow upward from various points on the main stem to approximately the same horizontal plane. The outer flowers open first.

 

cypsela

A dry, one-chambered, single-seeded fruit, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed from the wall of the inferior ovary and also from other tissues derived from the receptacle or hypanthium, does not split open at maturity, but relies on decay or predation to release the contents.

 

involucre

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

 

linear

Long, straight, and narrow, with more or less parallel sides, like a blade of grass.

 

phyllary

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

 

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.

 

rosette

A radiating group or cluster of leaves usually on or close to the ground.

 

wing

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

 

 

 

       

Visitor Photos

   
Share your photo of this plant.

Robert Briggs


  bull thistle   bull thistle

Bill Reynolds


Here are two images of Bull Thistle just before bloom In Pennington Co. MN.

  bull thistle   bull thistle
       

Plant

  bull thistle   bull thistle

       
       

MinnesotaSeasons.com Photos

   

Plant

  bull thistle    
       

Basal Rosette

  bull thistle    
       

Basal Leaves

  bull thistle   bull thistle
       
  bull thistle    
       

Involucre

  bull thistle    
       

Phyllaries

  bull thistle   bull thistle
       

Winged Stem

  bull thistle    
       
       

 

Camera

     

Slideshows

   
  Spear Thistle
Wez Smith
 
  Spear Thistle  
 
About

Spear Thistle (Cirsium vulgare).

 
     
  Cirsium vulgare
Matt Lavin
 
  Cirsium vulgare  
 
About

Introduced taprooted biennial often over 1 m tall, both leaf surfaces typically greenish and not covered by dense woolly hairs, upper leaf surfaces covered by minute spines or prickles, common where disturbance is frequent, such as roadsides and pastures.

 
     
  Bull Thistle (Spear Thistle) (Cirsium vulgare)
Andree Reno Sanborn
 
  Bull Thistle (Spear Thistle) (Cirsium vulgare)  
     
  Bull Thistle (Cirsium vulgare)
Bill Keim
 
  Bull Thistle (Cirsium vulgare)  
     
  Cirsium vulgare BULL THISTLE
Frank Mayfield
 
  Cirsium vulgare BULL THISTLE  

 

slideshow

     

Visitor Videos

   
Share your video of this plant.

     
     

Other Videos

 
  Identifying Bull Thistle, Cirsium vulgare
MyNatureApps
 
   
 
About

Uploaded on Jan 2, 2012

How to identify Bull Thistle, Cirsium vulgare, also known as Spear Thistle or Common Thistle. www.mynatureapps.com

 
     
  Bull Thistle (Cirsium vulgare) ~ Invasive Species
Wandering Sole TV
 
   
 
About

Published on Feb 10, 2014

Bull Thistle (Cirsium vulgare), also known as Spear Thistle, in the East Kootenays of British Columbia. It is a native plant of most of Europe, Western Asia, and NW Africa. In North America and Australia it has become naturalised and is a widespread weed often found colonising disturbed ground. It is a member of the Sunflower (Asteraceae) family. The flowers are a favourite with bees and butterflies (and on this day, ants).

Lacking natural predators and diseases, invasive plant species grow and spread rapidly throughout native ecosystems. Once established, invasive plants are very difficult to control and they choke out native species. This greatly affects wildlife habitat and rangeland. On a global scale, invasive pant and animal species are considered to be the second largest contributor to the loss of biodiversity, next to the loss of habitat.

 
     
  Environmental Laboratory - U.S. Army Corps of Engineers
EnvLabERDC
 
   
 
About

Published on Feb 15, 2013

Cirsium vulgare - Bull Thistle

 
     
  Weed of the Week #654-Bull Thistle (Air Date 10/17/10)
AgPhD
 
   
 
About

Uploaded on Oct 20, 2010

Don't sit on this weed. No, really, don't SIT on this weed. It's our Weed of the Week, Bull Thistle.

 
     
  Spear Thistle (Cirsium Vulgare) - 2012-07-13
W3stlander
 
   
 
About

Published on Jul 16, 2012

Cirsium vulgare (Spear Thistle) is a species of the genus Cirsium.

--------------------
De speerdistel (Cirsium vulgare, synoniem: Cirsium lanceolatum) is een plant uit het geslacht vederdistel.
52.05141 4.41610

 
     

 

Camcorder

         

Visitor Sightings

   
Share your sighting of this plant.

Robert Briggs
11/3/2016

 

bull thistle


Bill Reynolds
8/1/2014

Location: Pennington Co. MN

I didn't know these existed.  The Bull Thistle is just starting to bloom here in the north west of Minnesota.  The first two open are white.

bull thistle

Bill Reynolds
8/17/2013

Location: Pennington Co. MN

Bull Thistle just before bloom In Pennington Co. MN.

bull thistle

Bill Reynolds
8/11/2013

Location: Pennington Co. MN

Bull Thistle just before bloom In Pennington Co. MN.

bull thistle

     
     
 

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