Bull Thistle (Cirsium vulgare) is a species of the genus Cirsium, native throughout Europe, Asia and northern Africa, but also present in North America as an invasive weed. It is designated an "injurious weed" under the UK Weeds Act 1959 and a noxious weed in nine US states.
It is a tall biennial thistle, forming a rosette of leaves in the first year and a flowering stem about 1 foot tall in the second year. The leaves are very spiny, deeply lobed, up to 6-10 inches long (smaller on the upper part of the flower stem). The inflorescence is 1-2 inch diameter, pink-purple, with all the florets of similar form (no division into disc and ray florets). The seeds are .2 inches long, with a downy pappus which assists in wind dispersal.