Onopordum 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 : 244-245

125. Onopordum L. 2

Biennials. Stems spinose-winged, or absent. Leaves spinosedentate, pinnatifid to pinnatisect or almost pinnate, rarely subentire. Capitula globose to ovoid. Involucral bracts in several rows, coriaceous, densely imbricate at least near the base, spine-

tipped, glabrous to puberulent, sometimes glandular. Receptacle glabrous, with deep pits having dentate margins. Florets reddishpurple, rarely pink or white; corolla-tube slender; limb actinomorphic or saccate. Anthers with subulate apical appendages. Achenes 4-6 mm, subtetragonal, 4- to 5-ribbed, glabrous, dull; pappus-hairs scabrid or plumose, united into a ring at base, deciduous.

Unless otherwise stated, all species grow in rocky or stony ground, roadsides, waste places and similar dry, open habitats.

Unless otherwise indicated, descriptions apply to middle cauline leaves. The 2 outermost rows of bracts are referred to as outer bracts, the next 2-4 rows as middle bracts, followed by 1-2 rows of inner bracts, which are always erect, thinner and more obviously serrulate. The descriptions apply to the middle bracts, unless otherwise indicated.

Literature: G. Rouy, Bull. Soc. Bot. Fr. 43: 577-599 (1896). W. J. Drees, Baileya 14: 75-86 (1966). 1 Acaulescent; pappus at least 20 mm 1. acaulon 1 Stems present; pappus not more than 15 mm

2 Outer and middle involucral bracts expanded into a wide fimbriate-spiny apex 13. majorii 2 Involucral bracts without a fimbriate-spiny apex

3 Stem and mature leaves not tomentose or lanate, usually

± green, with multicellular hairs

4 Involucral bracts erect and closely imbricate

5 Stem-wings up to 7 mm wide; capitula ovoid-globose

3. laconicum 5 Stem-wings up to 20 mm wide; capitula conical-ovoid

4. nervosum 4 Involucral bracts with long, ± divergent spiny processes

6 Leaves with at least 10 pairs of lobes; capitula with ± dense arachnoid indumentum 7. argolicum 6 Leaves with not more than 8 pairs of lobes; capitula glabrous or with very sparse arachnoid indumentum

7 Capitula 35-50 mm in diameter; stem-wings with spines up to 15 mm 5. corymbosum 7 Capitula 55-70 mm in diameter; stem-wings with spines up to 5 mm 6. tauricum 3 Stem and leaves ± densely white- or greyish-tomentose or lanate, with unicellular hairs

8 Involucral bracts linear-subulate; corolla-lobes eglandular

2. acanthium 8 Involucral bracts lanceolate to ovate, often with a rigid spiny apical process; corolla-lobes glandular

9 Longest involucral bracts exceeding florets 8. caulescens 9 Involucral bracts not exceeding florets

10 Leaves pinnatisect, with oblong-linear lobes

9. messeniacum 10 Leaves pinnatifid, with triangular to palmate lobes

11 Stem sparsely spiny; leaves with fewer than 8 pairs of lobes 10. macracanthum 11 Stem densely spiny; leaves with at least 8 pairs of lobes

12 Capitula 50-70 mm in diameter; corolla 30-40 mm

11. bracteatum 12 Capitula 40-60 mm in diameter; corolla 25-35 mm

12. illyricum