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| 1 Heads 30-50 mm across in flower, the involucre (10-) 15-20 mm high; perennials from creeping rhizomes. |
| ..2 Phyllaries and peduncles densely pubescent with glandular hairs; longer phyllaries 14-17 mm long |
| ..2 Phyllaries and peduncles glabrous (but with sessile glands); longer phyllaries 10-15 mm long |
| 1 Heads 15-25 mm across in flower, the involucre 9-13 mm high; annuals. |
....3 Leaf base auricles rounded; mature achenes not transversely rugose |
| ....3 Leaf base auricles sagittate, the two lobes on either side of the stem coming to a point; mature achenes transversely rugose |