| Cyperus cupreus J. Presl & C. Presl, 1828 |
| Cyperus cuspidatus Kunth, 1815 |
| Cyperus cuspidatus f. exiguus (Nees) Kük., 1936 |
| Cyperus cymbiformis Liebm., 1850 |
| Cyperus cyrtolepis Torr. & Hook., 1836 |
| Cyperus cyrtolepis var. arenicola (Steud.) Boeckeler, 1868 |
| Cyperus cyrtolepis var. denticarinatus (Britton) Britton, 1886 |
| Cyperus densicaespitosus Mattf. & Kük., 1936 |
| Cyperus densiflorus Link, 1818 |
| Cyperus densus Humb. ex Link, 1820 |
| Cyperus denticulatus Schrad. ex Schult., 1824 |
| Cyperus dentoniae G.C. Tucker, 1983 |
| Cyperus depauperatus Vahl, 1805 |
| Cyperus diandrus Torr., 1819 |
| Cyperus diandrus var. capitatus Britton, 1886 |
| Cyperus diandrus var. castaneus S. Watson, 1880 |
| Cyperus difformis L., 1756 |
| Cyperus diffusus Vahl, 1805 |
| Cyperus diffusus subsp. tolucensis (Kunth) Borhidi, 1979 |
| Cyperus diffusus var. chorisanthos (C.B. Clarke) Kük., 1936 |