| Muhlenbergia purpusii Mez, 1921 |
| Muhlenbergia pusilla Steud., 1854 |
| Muhlenbergia quadridentata (Kunth) Kunth, 1829 |
| Muhlenbergia quadridentata (Kunth) Trin., 1824 |
| Muhlenbergia quitensis (Kunth) Hitchc., 1913 |
| Muhlenbergia racemosa (Michx.) Britton, Sterns & Poggenb., 1888 |
| Muhlenbergia ramosissima Vasey, 1886 |
| Muhlenbergia ramulosa (Kunth) Swallen, 1947 |
| Muhlenbergia reederorum Soderstr., 1967 |
| Muhlenbergia repens (J. Presl) Hitchc., 1912 |
| Muhlenbergia reverchonii Vasey & Scribn., 1892 |
| Muhlenbergia richardsonis (Trin.) Rydb., 1905 |
| Muhlenbergia rigens (Benth.) Hitchc., 1933 |
| Muhlenbergia rigida (Kunth) Kunth, 1829 |
| Muhlenbergia rigida (Kunth) Trin., 1824 |
| Muhlenbergia robusta (E. Fourn.) Hitchc., 1935 |
| Muhlenbergia scabra (Kunth) Trin. & Rupr., 1842 |
| Muhlenbergia schaffneri E. Fourn., 1885 |
| Muhlenbergia schaffneri var. longiseta Scribn., 1891 |
| Muhlenbergia schmitzii Hack., 1902 |