Lactuca serriola, 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 : 330

9. L. serriola L. , Cent. Pl. 2: 29 (1756)

( L. scariola L. ).

Annual or biennial. Stem up to 180 cm, rigidly erect, glabrous or setose, branched. Leaves rigid, spinulose on the midrib beneath; basal narrowly obovate-oblong, usually deeply pinnatifid (rarely undivided); cauline less deeply lobed, held vertically. Inflorescence a long, pyramidal or spike-like panicle. Involucre patent or deflexed in fruit. Capitula with 7-15(-35) florets. Ligules pale yellow. Achenes 6-8 mm; body elliptical, setose at apex, 5- to 9-ribbed, greyish; beak as long as body. 2л = 18. Roadsides, waste places and sand-dunes. Much of Europe, but only as an alien in the north. All except Fa Fe Hb Is No Rs (N) Sb; occurs in some of these as a casual.

Plants with densely setose inflorescence and spinose-ciliate leaves, restricted to the Mediterranean region, may be worthy of subspecific rank.