Centaurea uniflora subsp. uniflora

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 : 295

(a) Subsp. uniflora :

Stems simple, rarely branched. Leaves white-tomentose, entire; lower oblong-lanceolate, gradually attenuate into the petiole; middle cauline lanceolate. Involucre 17-22 mm in diameter, subglobose; appendages covering bracts. Pastures and rocky places in montane regions. S.W. Alps.