| Senna pumilio (A. Gray) H.S. Irwin & Barneby, 1979 |
| Senna purpusii (Brandegee) H.S. Irwin & Barneby, 1982 |
| Senna quinquangulata (Rich.) H.S. Irwin & Barneby, 1982 |
| Senna quinquangulata var. quinquangulata (Rich.) H.S. Irwin & Barneby, 1982 |
| Senna racemosa (Mill.) H.S. Irwin & Barneby, 1982 |
| Senna racemosa var. coalcomanica H.S. Irwin & Barneby, 1982 |
| Senna racemosa var. liebmannii (Benth.) H.S. Irwin & Barneby, 1982 |
| Senna racemosa var. moctezumae H.S. Irwin & Barneby, 1982 |
| Senna racemosa var. racemosa (Mill.) H.S. Irwin & Barneby, 1982 |
| Senna racemosa var. sororia H.S. Irwin & Barneby, 1982 |
| Senna reticulata (Willd.) H.S. Irwin & Barneby, 1982 |
| Senna ripleyana (H.S. Irwin & Barneby) H.S. Irwin & Barneby, 1979 |
| Senna roemeriana (Scheele) H.S. Irwin & Barneby, 1982 |
| Senna septemtrionalis (Viv.) H.S. Irwin & Barneby, 1982 |
| Senna siamea (Lam.) H.S. Irwin & Barneby, 1982 |
| Senna skinneri (Benth.) H.S. Irwin & Barneby, 1982 |
| Senna sousana H.S. Irwin & Barneby, 1982 |
| Senna spectabilis (DC.) H.S. Irwin & Barneby, 1982 |
| Senna spectabilis var. spectabilis (DC.) H.S. Irwin & Barneby, 1982 |
| Senna talpana H.S. Irwin & Barneby, 1982 |