| Cirsium
arvense
(L.) Scop. Canada thistle Introduced |
            
|
| Cirsium
discolor
(Muhl. ex Willd.) Sprengel field thistle Native |
  
|
| Cirsium
horridulum
Michaux yellow thistle Watch-Listed |
                  
|
| Cirsium
pumilum
(Nutt.) Sprengel pasture thistle Native |
                
|
| Cirsium
vulgare
(Savi) Ten. bull thistle Introduced |
                                     
|