| star-thistle | (n) Mediterranean annual or biennial herb having pinkish to purple flowers surrounded by spine-tipped scales; naturalized in America, Syn. caltrop, Centauria calcitrapa |
| barnaby's thistle | (n) European weed having a winged stem and hairy leaves; adventive in the eastern United States, Syn. yellow star-thistle, Centaurea solstitialis |