Noxious winter annual composite weeds, with rigidly erect branched stems to 1 m tall.
Plants are highly competitive with cereal crops and desirable rangeland species.
Because of their spiny nature, distaff thistles can injure the eyes and mouths of livestock forced to graze within dense populations of the weeds. Smooth and woolly distaff thistles are difficult to distinguish from one another and are sometimes classified as subspecies of C. lanatus . Species do not hybridize. Introduced from the Mediterranean region. See Comparison of spiny-leaved thistles .