Centaurea (Calcitrapa), (Heister ex Fabr.) Hayek

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1976, Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae), Cambridge University Press : 282

Subgen. Calcitrapa (Heister ex Fabr.) Hayek . Biennial. Leaves pinnatisect, not decurrent. Appendages not decurrent at base, palmate- or pinnate-spiny at apex, the apical spine much longer than the others. Pappus usually present.