Sonchus oleraceus, L.

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 : 327

3. S. oleraceus L. , Sp. Pl. 794 (1753).

Annual or biennial; stem 10-140 cm, simple or branched, often glandular-hairy in upper part and sometimes white-tomentose at base of capitula and on upper part of peduncles. Leaves glabrous, the lower undivided, with narrowly winged petiole, the upper larger, pinnatifid to pinnatisect, lyrate or sometimes runcinate with the lobes not or only slightly constricted at the base, with acute auricles. Involucral bracts 27-35. Ligules about as long as corolla-tube. Achenes 2-5-3-75 x 0-75-1 mm, oblanceolate, rugose between the ribs, weakly compressed; pappus 5-8 mm, more or less persistent. 2л = 32. Cultivated ground and waste places. Almost throughout Europe. All except Fa Is Sb.

Often difficult to distinguish from 2, and believed to be an allopolypoid derived from 1 and 2.