| Caspareopsis purpurea (L.) Pittier, 1945 |
| Casparia Kunth, 1824 |
| Casparia calderonii Rose, 1930 |
| Casparia lunarioides A. Gray ex Britton & Rose, 1930 |
| Cassia L., 1753 |
| Cassia absus L., 1753 |
| Cassia acapulcensis Kunth, 1823 |
| Cassia alata L., 1753 |
| Cassia alata var. perennis Pamp., 1907 |
| Cassia alata var. rumphiana DC., 1825 |
| Cassia andrieuxii Benth., 1871 |
| Cassia anisopetala Donn. Sm., 1904 |
| Cassia annunciata E.H.L. Krause, 1914 |
| Cassia apiculata M. Martens & Galeotti, 1843 |
| Cassia arborescens Mill., 1768 |
| Cassia argentea Kunth, 1824 |
| Cassia arida Rose, 1906 |
| Cassia armata S. Watson, 1879 |
| Cassia articulata Rose, 1909 |
| Cassia atomaria L., 1767 |