Centaurea biebersteinii subsp. biebersteinii

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 : 279

(a) Subsp. biebersteinii (C. micranthos S. G. Gmelin ex Hayek): Lower leaves 2-pinnatisect, more or less glabrescent; segments 1-1-5 mm wide, narrowly linear. Involucre 11 x 7 mm, ovoid; appendages mucronate. Throughout the range of the species except C. & S. Bulgaria.