Onopordum acanthium, 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 : 245

2. O. acanthium L. , Sp. Pl. 827 (1753).

Plant up to 300 cm. Stem yellowish, more or less hairy, the wings not reticulateveined, with spines up to 5 mm. Leaves up to 35 x 20 cm, oblong-ovate to broadly lanceolate or ovate, sessile, sinuatedentate or with 6-8 pairs of broadly triangular teeth with an apical spine 5-10 mm, greyish-green and sparsely lanate above. Capitula subglobose, solitary or in terminal clusters of 2-5; involucral bracts gradually tapering into a spine up to 5 mm, not keeled, puberulent outside. Corolla 14-25 mm, purplish or white. Achenes 4-5 mm, marbled greyish-black; pappus 7-9 mm, pale reddish. Europe northwards to N. France and C. Russia, but local in the extreme south; naturalized or casual in the north. Al Au *Be Bu Co Cz Ga Ge Gr He *Ho Hs Hu It Ju Lu Rm Rs (C, W, K, E) [Br Da Rs (B) Su].

The boundaries between native, naturalized and casual occurrence are hard to define.

1 Capitula in clusters of 3-5; corolla up to 20 mm (b) subsp. gautieri

1 Capitula solitary or in clusters of 2-3; corolla more than 20 mm 2 Stem-wings up to 15 mm wide; capitula with sparse arachnoid indumentum (a) subsp. acanthium

2 Stem-wings up to 7 mm wide; capitula with dense arachnoid indumentum (c) subsp. pamassicum