| | 1. Flowers ± sessile (immediately subtended by 2 bracts); inflorescence generally dense, units often ± flat-topped |
| |
| | 2. Biennial; basal rosette conspicuous; corolla lobes 5–7 mm, generally puberulent outside; alien, North Coast |
| C. erythraea |
| | 2' Annual; basal rosette 0 or weak; corolla lobes 2–5 mm, glabrous outside; native, n California |
| |
| | 3. Corolla lobes 2–5 mm; stigma oblong |
| C. muehlenbergii |
| | 3' Corolla lobes 8–10 mm; stigma tapered, minute |
| 2 C. trichanthum |
| | 1' Most flowers ± clearly pedicelled above subtending bracts; inflorescence generally ± open |
| |
| | 4. Corolla not very showy (lobes generally 2–7 mm, generally < tube); undehisced anthers 1–1.5 mm |
| |
| | 5. Pedicels generally < 10 mm; corolla lobes elliptic, overlapping, generally flat; ± coastal |
| C. davyi |
| | 5' Pedicels 10–50 mm; corolla lobes appearing ± linear, not overlapping, often inrolled; inland |
| C. exaltatum |
| | 4' Corolla ± showy (lobes generally 6–20 mm, often > tube); undehisced anthers 3–6 mm (except stunted plants) |
| |
| | 6. Corolla lobes generally 5–9 mm; stigma minute, appearing ± unlobed — Inner North Coast Ranges, San Francisco Bay Area |
| 2 C. trichanthum |
| | 6' Corolla lobes generally 8–20 mm (except stunted plants); stigma lobes separately stalked, 1–2 mm when fresh, fan-shaped |
| |
| | 7. Basal leaves generally rosetted, generally linear-oblanceolate; corolla lobes 8–12 mm; uncommon; e Sonoran Desert |
| C. calycosum |
| | 7' Rosette 0; leaves narrowly oblong to ovate; corolla lobes (2)10–20 mm; California Floristic Province, Mojave Desert |
| C. venustum
|