| Crypsis virginica (L.) Nutt., 1818 |
| Cryptochloa Swallen, 1942 |
| Cryptochloa concinna (Hook. f.) Swallen, 1942 |
| Cryptochloa granulifera Swallen, 1942 |
| Cryptochloa strictiflora (E. Fourn.) Swallen, 1942 |
| Cryptopyrum Heynh., 1846 |
| Cryptopyrum richardsoni Heynh., 1846 |
| Cryptostachys Steud., 1854 |
| Crypturus Link, 1844 |
| Cteniinae P.M. Peterson, Romasch. & Herrera, 2014 |
| Ctenium Panz., 1813 |
| Ctenium glandulosum Scribn. & J.G. Sm., 1896 |
| Ctenium planifolium (J. Presl) Kunth, 1833 |
| Ctenium plumosum (Hitchc.) Swallen, 1939 |
| Ctenopsis De Not., 1847 |
| Ctenopsis (De Not.) F. Herm., 1936 |
| Ctenopsis (De Not.) F. Herm., 1936 |
| Curtopogon P. Beauv., 1812 |
| Curtopogon gracilis Nees ex Trin. & Rupr., 1842 |
| Cyclostachya Reeder & C. Reeder, 1963 |