| Coleanthinae Rouy, 1913 |
| Coleataenia Griseb., 1879 |
| Coleataenia caricoides (Nees ex Trin.) Soreng, 2010 |
| Coleataenia stenodes (Griseb.) Soreng, 2010 |
| Coleataenia tenera (Beyr. ex Trin.) Soreng, 2010 |
| Coliquea Steud. ex Bibra., 1853 |
| Colladoa Cav., 1799 |
| Colobachne P. Beauv., 1812 |
| Colobanthium (Rchb.) G. Taylor, 1966 |
| Colobanthus Trin., 1830 |
| Colpodium Trin., 1820 |
| Colpodium junceum (P. Beauv.) Trin., 1821 |
| Columbiana Hitchc. & Chase, 1910 |
| Commelinidium Stapf, 1920 |
| Commutata Hitchc. & Chase, 1910 |
| Comopyrum Á. Löve, 1982 |
| Cornucopiae L., 1753 |
| Cornucopiae altissima Walter, 1788 |
| Cornucopiae hyemalis Walter, 1788 |
| Cornucopiae perennans Walter, 1788 |