Carduus hamulosus subsp. hamulosus

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 : 226

(a) Subsp. hamulosus ( C. pseudocollinus (Schmalh.) Klokov ): Leaves with numerous multicellular and a few unicellular hairs beneath. Involucral bracts glabrous or nearly so. Throughout the range of the species.