| | 1. Leaves compound, base of main division petiole-like and unwinged |
| |
| | 2. Leaves palmate (sometimes palmate-ternate); ultimate segment of main axis 4–30 mm wide |
| |
| | 3. Main leaf divisions often ± 5, central division generally 2–4 cm; styles 2 × calyx; bracts 1–2 mm; fruit sometimes clearly stalked above receptacle; common, widespread, variable |
| 2 S. crassicaulis |
| | 3' Main leaf divisions ± 3, central division generally 4–7 cm; styles ± = calyx; bracts 3–5 mm; fruit ± sessile above receptacle; uncommon, coastal |
| 2 S. hoffmannii |
| | 2' Leaves somewhat pinnate (first division often ternate, others pinnate); ultimate segment of main axis 1–5 mm wide |
| |
| | 4. Fruit with many clearly hooked bristles |
| |
| | 5. Staminate flowers 4–6 per umbel, inconspicuous; stem leafy, ± erect |
| S. bipinnata |
| | 5' Staminate flowers 7–12 per umbel, conspicuous; stem ± leafless, branches often spreading widely from near base |
| S. graveolens |
| | 4' Fruit with ± rounded tubercles, hooked bristles 0 or few |
| |
| | 6. Plant from a taproot that is rarely tuber-like; staminate flowers slightly > fruit, not very conspicuous — North Coast, Cascade Range Foothills |
| S. tracyi |
| | 6' Plant from a distinct, spheric or irregular tuber; staminate flowers often >> fruit and very conspicuous |
| |
| | 7. Corolla straw- or salmon-colored; fruit 2.5–3 mm, most tubercles nipple-like or with a bristle; San Francisco Bay Area |
| S. saxatilis |
| | 7' Corolla yellow; fruit 1.5–2 mm, tubercles unarmed; widespread, variable |
| S. tuberosa |
| | 1' Leaves simple, entire to deeply lobed or cut, axis of main division with at least a narrow, toothed wing throughout |
| |
| | 8. Bracts yellow, >> heads; plant prostrate; leaves bright yellowish green when flowers open |
| S. arctopoides |
| | 8' Bracts greenish, inconspicuous, < or = heads; plant spreading to erect; leaves green when flowers open |
| |
| | 9. Leaf margins not or barely toothed, some basal leaves entire |
| S. maritima |
| | 9' Leaf margins sharply toothed, all leaves ± lobed |
| |
| | 10. Leaves palmately lobed or dissected; main divisions 3–5 |
| |
| | 11. Main leaf division narrowed to an almost petiole-like base |
| 2 S. hoffmannii |
| | 11' Main leaf division often 10 mm or more wide at base |
| |
| | 12. Outline of leaf margin ± rounded, teeth generally ± 1 mm; plant stout, 24–120 cm, generally branched well above base; common, widespread, variable |
| 2 S. crassicaulis |
| | 12' Outline of leaf margin sharply angled, teeth generally ± 2 mm; plant slender, 5–30 cm, generally branched near base; North Coast, Central Coast |
| S. laciniata |
| | 10' Leaves somewhat pinnately lobed or dissected; main divisions generally 7 or more, each generally deeply cut |
| |
| | 13. Leaves appearing almost palmate, with some pinnate divisions — corolla yellow; Southwestern California |
| S. arguta |
| | 13' Leaves clearly pinnate, with some ternate divisions |
| |
| | 14. Corolla purple or yellow; fruits 3–8 per head; staminate flowers inconspicuous, < fruit; widespread |
| S. bipinnatifida |
| | 14' Corolla yellow; fruits 1–5 per head; staminate flowers conspicuous, > fruit; Klamath Ranges (Del Norte Co.) |
| S. peckiana
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