| | 1. Leaves very narrowly linear, thread-like, not decurrent; annual |
| H. amarum |
| | 1' Leaves wider, with flat blade, decurrent; annual or perennial herb |
| |
| | 2. Leaf margins ± toothed |
| H. autumnale |
| | 3. Ligules 1.5–2.5 cm; herbage sparsely puberulent or becoming glabrous |
| var. grandiflorum |
| | 3' Ligules ± 1 cm; herbage densely puberulent and glandular |
| var. montanum |
| |
| | 4. Heads several–many; ligules 4–10 mm (sometimes rays 0); disk corollas generally 4-lobed, 2–2.7 mm; pappus < or = 1 mm |
| H. puberulum |
| | 4' Heads 1–few; ligules 13–30 mm; disk corollas 5-lobed, 3–5 mm; pappus 1.3–4.5 mm |
| |
| | 5. Peduncles sparsely to moderately hairy; pappus generally 1.3–2.7 mm; widespread but generally not North Coast |
| H. bigelovii |
| | 5' Peduncles generally densely hairy; pappus generally 3–4.5 mm; North Coast |
| H. bolanderi
|