Centaurea phrygia subsp. phrygia

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 : 294

(a) Subsp. phrygia ( C. austriaca Willd. ): Stems up to 80 cm, sparingly branched. Leaves green, hairy when young. Capitula solitary. Involucre 15-18 x 14-16 mm, globose; appendages of middle bracts ovate, black, gradually attenuate into a filiform, shortly recurved apex; appendages of inner bracts exserted, distinctly exceeding those of the middle bracts. Florets purple, the outer radiate. 2л = 22. In the north and west parts of the range of the species, south-eastwards to Czechoslovakia and Romania.