| 1 | Achenes without a dorsal tooth or transverse ventral ridge, c. 15-30 achenes per head |
| 1' | Achenes with a dorsal tooth and transverse ridge |
| 2 | Achenes c. 15-30, 4-6 x 2-4 mm, beak conspicuous, ascending, remote from dorsal tooth |
| 2' | Achenes c. 30-50, c. 2-5 x 2 mm, beak rather short, pressed against dorsal tooth |
| 3 | Transverse ventral ridge of achene obscurely sulcate or dentate; plants 15-30 cm high (flowers red, yellow or orange) |
| 3' | Transverse ventral ridge of achene conspicuously toothed; plants seldom more than 12 cm high (flowers always yellow?) |
