Centaurea, (Hayek) Dostal

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 : 292

Sect. Nigrescentes (Hayek) Dostál . Appendages triangular, ovate-triangular or -lanceolate to orbicular, usually not covering bracts, the margin pectinate-fimbriate, the terminal fimbriae shorter than the lateral. Pappus present or absent. The species of this Section, although well-characterized, are very closely related to each other and transitional variants between them often occur.