| 1 | Cirsium | altissimum | Tall Thistle | Aster Family | Asteraceae | Magnoliopsida |
| 2 | Cirsium | arvense | Canada Thistle | Aster Family | Asteraceae | Magnoliopsida |
| 3 | Cirsium | discolor | Field Thistle | Aster Family | Asteraceae | Magnoliopsida |
| 4 | Cirsium | horridulum var. horridulum | Yellow Thistle | Aster Family | Asteraceae | Magnoliopsida |
| 5 | Cirsium | muticum | Swamp Thistle | Aster Family | Asteraceae | Magnoliopsida |
| 6 | Cirsium | pumilum | Pasture Thistle | Aster Family | Asteraceae | Magnoliopsida |
| 7 | Cirsium | vulgare | Bull Thistle | Aster Family | Asteraceae | Magnoliopsida |