S. arvensis: stem 3-4 feet high, simple, leafy; leaves long, acute, lanceolate, runcinate, finely-toothed, cordate at the base, the uppermost entire; heads corymbose, large; florets yellow; involucre and peduncles glandular-hairy; root creeping. - Cornfields. Fl. August, September.
S. palustris: stem 4-6 feet high, simple, leafy; leaves linear-lanceolate, the lower runcinate, the upper simple, all arrow-shaped, spinosely-ciliated, with acute auricles; heads corymbose; florets lemon-coloured; involucre and peduncles glandular-hairy; root without scions. - Marshes, rare. Fl. July to September.