Carduus litigiosus subsp. litigiosus

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 : 225

(a) Subsp. litigiosus ( C. sanctae-balmae Loisel .): Wings of stem dentate, up to 6 mm wide, with an apical spine up to 4 mm. Lower leaves up to 15 x 3-5 cm; leaves with 10-12 pairs of triangular-dentate lobes each with an apical spine up to 4 mm. Outer involucral bracts c. 6 mm. Throughout the range of the species.