Sonchus arvensis subsp. arvensis

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 : 328

(a) Subsp. arvensis :

Capitula and upper parts of peduncles densely glandular-hairy. Longest involucral bracts 14-17 mm. Throughout the range of the species, except for parts of the Balkan peninsula.