Lactuca, (Cass.) Bentham. Inflorescence

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 : 329

Sect. Phoenixopus (Cass.) Bentham. Inflorescence a pyramidal or spike-like panicle with capitula solitary or in fascicles. Capitula with 4-8 florets. Achenes with 5—11 ribs, gradually contracted into a concolorous beak not longer than body.