| 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 |
| Cassia tortuosa L.B. Sm. & B.G. Schub., 1939 |
| Cassia totonaca Sessé & Moc., 1893 |
| Cassia trichocraspedon Sandwith, 1936 |
| Cassia trichoneura Brandegee, 1915 |
| Cassia triflora Vahl, 1807 |
| Cassia tristicula Benth., 1823 |
| Cassia undulata Benth., 1840 |
| Cassia uniflora Mill., 1768 |
| Cassia unijuga Rose, 1899 |
| Cassia villosa Mill., 1768 |