| Coreopsis serrulata Poir., 1811 |
| Coreopsis teotepecensis Paray, 1958 |
| Coreopsis tetragona Cerv. ex La Llave & Lex., 1824 |
| Coreopsis tinctoria Nutt., 1821 |
| Coreopsis trichosperma Michx., 1803 |
| Coreopsis trichosperma var. aurea (Aiton) Nutt., 1818 |
| Corethrogyne DC., 1836 |
| Corethrogyne brevicula Greene, 1910 |
| Corethrogyne caespitosa Greene, 1897 |
| Corethrogyne filaginifolia (Hook. & Arn.) Nutt., 1840 |
| Corethrogyne filaginifolia var. virgata (Benth.) A. Gray, 1876 |
| Corethrogyne virgata Benth., 1844 |
| Coronocarpus Schumach., 1827 |
| Correllia A.M. Powell, 1973 |
| Correllia montana A.M. Powell, 1973 |
| Cosmophyllum K. Koch, 1855 |
| Cosmos Cav., 1791 |
| Cosmos atrosanguineus (Hook. f.) Voss, 1894 |
| Cosmos bipinnatus Cav., 1791 |
| Cosmos carvifolius Benth., 1845 |