| 1. Inflorescence panicle-like; branches in 24 distinct whorls, spreading |
| C. verticillata |
| 1' Inflorescence umbel-like; branches ± erect |
| |
| 2. Perennial, generally from stolons; vestigial florets generally 2+ |
| C. gayana |
| 2' Annual, generally < 5 dm; vestigial florets generally 1 |
| C. virgata
|