Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more precisely known as plume thistles. These differ from other thistle genera (Carduus, Silybum and Onopordum) in having feathered hairs to their achenes. The other genera have a pappus of simple unbranched hairs. They are mostly native to Eurasia and northern Africa, with about 60 species from North America (although several species have been introduced outside their native ranges).