| | 1. Leaves simple, shallowly lobed to generally entire, rarely ± dissected |
| |
| | 2. Plant ± scapose, rarely with 1–2 cauline leaves, 2–12 cm; basal leaves many, blade base ± tapered; inflorescence in fruit ± umbel-like |
| C. bellidifolia var. pachyphylla |
| | 2' Plant with cauline leaves, 15–50 cm; basal leaves few, blade base abruptly narrowed; inflorescence in fruit elongate |
| |
| | 3. Cauline leaves from base to inflorescence; rhizome leaves 0; stems amid generally dense rhizomes |
| C. cordifolia var. lyallii |
| | 3' Cauline leaves near inflorescence; rhizome leaves present; stems from ends of elongate rhizomes |
| C. pachystigma |
| | 4. Cauline leaves 1-palmately or -pinnately ± dissected |
| var. dissectifolia |
| | 4' Cauline leaves entire or shallowly lobed |
| var. pachystigma |
| | 1' Leaves or at least lower cauline palmately or pinnately lobed to compound |
| |
| | 5. Stem widened to strong attachment with rhizome or rhizome 0; rhizome leaves generally 0; cauline leaves pinnately lobed to compound |
| |
| | 6. Annual or biennial from fibrous roots or weak taproot |
| |
| | 7. Basal leaves 0–few, not rosetted, generally deciduous; lower stem hairs few or generally 0 |
| C. pensylvanica |
| | 7' Basal leaves many, generally ± rosetted, persistent; lower stem hairs 0–many |
| |
| | 8. Stems 1–many, erect, 5–30 cm, outer 0 or decumbent; fruit < 1 mm wide; alien |
| C. hirsuta |
| | 8' Stems 1–several, erect to ascending, generally > 20 cm; fruit 1–2 mm wide; native |
| C. oligosperma |
| | 6' Perennial from rhizomes or strong taproot |
| |
| | 9. Petals 8–14 mm; style 1.5–6 mm |
| |
| | 10. Rhizome elongate, > 3 cm, not tuber-like, ± spreading; style 1.5–3(4) mm; leaflets widely dentate to lobed |
| C. angulata |
| | 10' Rhizome short, < 2 cm, tuber-like, ± spreading to ± erect; style 3–6 mm; leaflets or lobes entire to wavy or dentate |
| 2 C. californica (see 17. for vars.) |
| | 9' Petals 4–6 mm; style ± 1–1.2 mm |
| |
| | 11. Basal leaves pinnately lobed; rhizome ± tuber-like at stem base |
| C. occidentalis |
| | 11' Basal leaves generally entire to shallowly palmately lobed; rhizome not tuber-like at stem base |
| C. breweri |
| | 12. Leaflets of lower cauline leaves wedge-shaped to truncate at base; rhizome ± elongate, spreading |
| var. breweri |
| | 12' Leaflets of lower cauline leaves cordate at base; rhizome generally short, ± erect |
| var. orbicularis |
| | 5' Stem narrowed to weak attachment with rhizome; rhizome leaves present; cauline leaves pinnately or generally palmately lobed to compound |
| |
| | 13. Stem slender, < 2 dm; rhizome ovoid to elongate, generally with ovoid, tuber-like swelling from which leaf arises, 0.5–3 cm; inflorescence in fruit ± umbel-like |
| C. nuttallii |
| | 14. Rhizome leaf simple, ± entire to shallowly lobed |
| var. nuttallii |
| | 14' Rhizome leaf subpalmately compound, leaflets 3–5, ± entire to ± lobed |
| |
| | 15. Rhizome leaflets (3)5, oblong, ± entire, 6–10 mm wide |
| var. covilleana |
| | 15' Rhizome leaflets 3–5, ovate to ± elliptic to obovate, toothed or lobed, 10–20 mm wide |
| |
| | 16. Rhizome leaflets ± sessile, toothed or lobed; rhizome elongate, generally whitish |
| var. dissecta |
| | 16' Rhizome leaflets stalked, toothed; rhizome ovoid to slightly elongate, generally yellowish |
| var. gemmata |
| | 13' Stem ± stout, 2–7 dm; rhizome ovoid to subspheric, tuber-like, < 2 cm; inflorescence in fruit elongate |
| 2 C. californica |
| | 17. Rhizome leaves 1–2-pinnate, leaflets 5–9, often lobed |
| var. cuneata |
| | 17' Rhizome leaves simple, entire, or leaflets 3, rarely 5 and ± pinnately arranged |
| |
| | 18. Rhizome leaves generally with 3 leaflets, rarely with 5 or simple, entire |
| |
| | 19. Leaflets or lobes of cauline leaves generally ovate or wider, thin, generally sharp-toothed |
| var. californica |
| | 19' Leaflets or lobes of cauline leaves generally oblong to linear, thickish, generally entire or teeth small, few or only 1 at tip |
| var. integrifolia |
| | 18' Rhizome leaves simple |
| |
| | 20. Cauline leaves simple; rhizome leaf blade margin shallowly wavy |
| var. cardiophylla |
| | 20' Cauline leaves generally compound; rhizome leaf blade margin wavy to deeply dentate |
| var. sinuata
|