| 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 |
| Reboulea obtusata var. obtusata (Michx.) A. Gray, 1848 |
| Reboulea obtusata var. pubescens (Scribn. & Merr.) Farw., 1916 |
| Reboulea truncata Torr. ex Munro, 1862 |
| Reederochloa Soderstr. & H.F. Decker, 1964 |
| Reederochloa eludens Soderstr. & H.F. Decker, 1964 |
| Reimaria Humb. & Bonpl. ex Flüggé, 1810 |
| Reimaria candida Humb. & Bonpl. ex Flüggé, 1810 |
| Reimaria diffusa Spreng., 1822 |
| Reimaria elegans Humb. & Bonpl. ex Flüggé, 1810 |
| Reimaria oligostachya Munro ex Benth., 1881 |
| Reimarochloa Hitchc., 1909 |
| Reimarochloa oligostachya (Munro ex Benth.) Hitchc., 1909 |
| Rendlia Chiov., 1914 |
| Rettbergia Raddi, 1823 |