| |
| 2. Corollas generally > 25 mm |
| C. sulphurea |
| 2' Corollas generally 1020 mm |
| |
| 3. Central spines of main phyllaries 510 mm |
| C. melitensis |
| 3' Central spines of main phyllaries 1025 mm |
| C. solstitialis |
| 1' Corollas white to pink, blue, or purple |
| |
| 4. Main phyllaries ± spine-tipped |
| |
| 5. Central spines of main phyllaries 1025 mm |
| |
| 6. Young leaves ± gray-tomentose; involucre body 68 mm diam |
| C. calcitrapa |
| 6' Young leaves minutely bristly, green; involucre body 814 mm diam |
| C. iberica |
| 5' Central spines of main phyllaries generally < 10 mm |
| |
| 7. Outer corollas ± ray-like, 2030 mm, purple |
| 2 C. diluta |
| 7' Outer corollas not or barely enlarged, 713 mm, white to pink or pale purple |
| |
| 8. Involucre 1013 mm; corollas 1213 mm |
| C. diffusa |
| 8' Involucre 78 mm; corollas 79 mm |
| C. squarrosa |
| 4' Main phyllaries not spine-tipped |
| |
| |
| 10. Herbage ± tomentose; inner corollas 1015 mm |
| C. cyanus |
| 10' Herbage (sub)glabrous; inner corollas ± 20 mm |
| 2 C. diluta |
| |
| 11. Flowers all fruiting, corollas ± equal |
| C. nigra |
| 11' Outer flowers sterile, ± ray-like; inner flowers fruiting |
| |
| C. maculosa |
| C. ×pratensis
|