| | 1. Flowers orange or white |
| |
| | 2. Flowers white; stolons 0; native per of forests |
| H. albiflorum |
| | 2' Flowers orange; stolons present; weed |
| H. aurantiacum |
| |
| | 3. Leaves glabrous on one or both surfaces |
| |
| | 4. Leaves glabrous on lower surface, sparsely hairy on upper; phyllaries glabrous or with a few scattered hairs; flowers 8–20 |
| H. bolanderi |
| | 4' Leaves glabrous on both surfaces; phyllaries lightly tomentose and with short, glandular hairs; flowers 20–35 |
| H. gracile |
| | 3' Leaves ± hairy on both surfaces |
| |
| | 5. Leaves and stems grayish with short, stellate hairs and sometimes longer hairs; fruits 5–6 mm |
| H. greenei |
| | 5' Leaves and stems with long, unbranched hairs; fruits 2–3 mm |
| |
| | 6. Stems mostly 0.8–3 dm; leaves densely hairy; flowers 6–15 |
| H. horridum |
| | 6' Stems mostly 3–10 dm; leaves sparsely to moderately hairy; flowers 14–50 |
| |
| | 7. At least some leaves with prominent, widely spaced teeth; c&s California |
| H. argutum |
| | 7' Leaves all entire; n-most California |
| H. scouleri
|