| Cladium californicum (S. Watson) O'Neill, 1941 |
| Cladium effusum (Sw.) Torr., 1836 |
| Cladium jamaicense Crantz, 1766 |
| Cladium jamaicense subsp. jamaicense Crantz, 1766 |
| Cladium mariscus (L.) Pohl, 1809 |
| Cladium mariscus subsp. californicum (S. Watson) Govaerts, 1999 |
| Cladium mariscus var. californicum S. Watson, 1880 |
| Cladium occidentale Schrad., 1806 |
| Clavula Dumort., 1827 |
| Clavula acicularis (L.) Dumort., 1827 |
| Cyperaceae Juss., 1789 |
| Cypereae Dumort., 1829 |
| Cyperinae Pax, 1886 |
| Cyperoideae Kostel., 1831 |
| Cyperus L., 1753 |
| Cyperus acicularis (L.) With., 1796 |
| Cyperus acuminatus Torr. & Hook., 1836 |
| Cyperus acuminatus var. cyrtolepis (Torr. & Hook.) Kük., 1936 |
| Cyperus acutiusculus Lag., 1816 |
| Cyperus aggregatus (Willd.) Endl., 1842 |