Centaurea aspera subsp. aspera

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 : 284

(a) Subsp. aspera :

Stems up to 50 cm, erect or ascending, muchbranched. Lower leaves oblong-lanceolate, pinnatifid to sinuatedentate; upper linear-lanceolate. Involucre c. 20 mm in diameter, globose; appendages half as long as bract, with 3-5 divergent, yellow spines, the apical longer. Throughout the range of the species.