| Cassia seleriana Harms, 1899 |
| Cassia septemtrionalis Viv., 1802 |
| Cassia serpens L., 1762 |
| Cassia siamea Lam., 1785 |
| Cassia simulans (Britton & Rose) Lundell, 1937 |
| Cassia skinneri Benth., 1871 |
| Cassia spectabilis DC., 1813 |
| Cassia standleyi (Britton & Rose) Standl., 1937 |
| Cassia stenocarpa Vogel, 1837 |
| Cassia stenosepala L.B. Sm. & B.G. Schub., 1939 |
| Cassia strobilacea Kunth, 1823 |
| Cassia tarantan Kunth, 1823 |
| Cassia tenuicaulis M.E. Jones, 1933 |
| Cassia texana Buckley, 1861 |
| Cassia thonningii DC., 1825 |
| Cassia tomentosa L. f., 1782 |
| Cassia tonduzii Standl., 1919 |
| Cassia tora L., 1753 |
| Cassia tora var. obtusifolia (L.) Haines, 1922 |
| Cassia toroides Roxb., 1828 |