| Caucalis L., 1753 |
| Caucalis microcarpa Hook. & Arn., 1839 |
| Celeri Adans., 1763 |
| Celeri graveolens (L.) Britton, 1913 |
| Centella L., 1763 |
| Centella asiatica (L.) Urb., 1879 |
| Centella erecta (L. f.) Fernald, 1940 |
| Centella renifolia (Lag.) Urb., 1879 |
| Chaerophyllum L., 1753 |
| Chaerophyllum orizabae (I.M. Johnst.) K.F. Chung, 2007 |
| Chaerophyllum tolucanum (I.M. Johnst.) K.F. Chung, 2007 |
| Cicuta L., 1753 |
| Cicuta douglasii (DC.) J.M. Coult. & Rose, 1900 |
| Cicuta maculata L., 1753 |
| Cicuta mexicana J.M. Coult. & Rose, 1900 |
| Coaxana J.M. Coult. & Rose, 1895 |
| Coaxana bambusioides Mathias & Constance, 1973 |
| Coaxana ebracteata Rose, 1906 |
| Coaxana purpurea J.M. Coult. & Rose, 1895 |
| Conioselinum Fisch. ex Hoffm., 1814 |