| Conium maculatum L., 1753 |
| Coriandrum L., 1753 |
| Coriandrum sativum L., 1753 |
| Coulterophytum B.L. Rob., 1892 |
| Coulterophytum brevipes J.M. Coult. & Rose, 1900 |
| Coulterophytum holwayi Rose, 1905 |
| Coulterophytum laxum B.L. Rob., 1892 |
| Coulterophytum macrophyllum J.M. Coult. & Rose, 1900 |
| Crantzia Nutt., 1818 |
| Crantzia lineata (Michx.) Nutt., 1818 |
| Crantzia schaffneriana Schltdl., 1854 |
| Cuminum L., 1753 |
| Cyclospermum Lag., 1821 |
| Cyclospermum leptophyllum (Pers.) Sprague ex Britton & P. Wilson, 1925 |
| Cyclospermum leptophyllum var. leptophyllum (Pers.) Sprague ex Britton & P. Wilson, 1925 |
| Cymopterus Raf., 1819 |
| Cymopterus fendleri A. Gray, 1849 |
| Cymopterus glomeratus (Nutt.) DC., 1830 |
| Cymopterus glomeratus var. fendleri (A. Gray) R.L. Hartm., 2006 |
| Cymopterus multinervatus (J.M. Coult. & Rose) Tidestr., 1935 |