| Rhynchelytrum roseum (Nees) Stapf & C.E. Hubb., 1930 |
| Rhynchelytrum tonsum (Nees) Lanza & Mattei, 1910 |
| Rhytachne Desv. ex Ham., 1825 |
| Rhytachne guianensis (Hitchc.) Clayton, 1966 |
| Rhytachne rottboellioides Desv., 1825 |
| Rhytachne subgibbosa (Winkl. ex Hack.) Clayton, 1966 |
| Riedelia Kunth, 1833 |
| Riedelia mikanii Trin. ex Kunth, 1830 |
| Ripidium Trin., 1820 |
| Ripidium japonicum (Trin.) Trin., 1820 |
| Robynsiochloa Jacq.-Fél, 1960 |
| Roegneria K. Koch, 1848 |
| Roegneria canadensis (L.) Hyl., 1953 |
| Roegneria pauciflora (Schwein.) Hyl., 1945 |
| Roegneria trachycaulon (Link) Nevski, 1934 |
| Roshevitzia Tzvelev, 1968 |
| Roshevitzia diplachnoides (Steud.) Tzvelev, 1970 |
| Roshevitzia glomerata (Walter) Tzvelev, 1970 |
| Roshevitzia japonica (Thunb.) Tzvelev, 1970 |
| Rostraria Trin., 1820 |