Centaurea (Cynaroides), Dostal. Biennial

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 : 270

Subgen. Cynaroides Dostál. Biennial , rarely perennial. Leaves undivided, rarely the basal lyrate-pinnatipartite. Appendages of middle bracts with a persistent, rigid apical spine. Pappus present.