| Quinquesetum Parodi, 1946 |
| Rabdochloa P. Beauv., 1812 |
| Rabdochloa domingensis (Jacq.) P. Beauv., 1812 |
| Rabdochloa dubia (Kunth) Kuntze ex Stuck., 1904 |
| Rabdochloa imbricata (Thurb.) Kuntze, 1891 |
| Rabdochloa mucronata (Michx.) P. Beauv., 1812 |
| Rabdochloa spicata (Nees) Kuntze ex Stuck., 1904 |
| Rabdochloa virgata (Sw.) P. Beauv., 1812 |
| Raddia Mazziari, 1834 |
| Raram Adans., 1763 |
| Raspailia J. Presl, 1830 |
| Raspailia agrostoidea J. Presl, 1830 |
| Raspailia rupestris Turcz. ex Kom., 1934 |
| Reana Brign., 1849 |
| Reana luxurians Durieu, 1872 |
| Rebentischia Opiz, 1854 |
| Reboulea Kunth, 1830 |
| Reboulea gracilis Kunth, 1830 |
| Reboulea obtusata (Michx.) A. Gray, 1848 |
| Reboulea obtusata var. lobata Farw., 1916 |