| Panicum columbianum var. oricola (Hitchc. & Chase) Fernald, 1934 |
| Panicum columbianum var. siccanum (Hitchc. & Chase) B. Boivin, 1967 |
| Panicum columbianum var. thinium (Hitchc. & Chase) Hitchc. & Chase, 1908 |
| Panicum columbiense Kuntze, 1898 |
| Panicum commelinifolium Ashe, 1898 |
| Panicum commonsianum Ashe, 1898 |
| Panicum commonsianum var. euchlamydeum (Shinners) R.W. Pohl, 1947 |
| Panicum commutatum Schult., 1824 |
| Panicum commutatum var. ashei (T.G. Pearson ex Ashe) Fernald, 1934 |
| Panicum commutatum var. consanguineum (Kunth) Beal, 1896 |
| Panicum commutatum var. joorii (Vasey) Fernald, 1937 |
| Panicum commutatum var. latifolium Scribn., 1893 |
| Panicum commutatum var. minor Vasey, 1889 |
| Panicum comophyllum Nash, 1903 |
| Panicum compactum Sw. ex Wikstr., 1829 |
| Panicum compositum L., 1753 |
| Panicum compositum var. fimbriusculum Döll, 1877 |
| Panicum compressicaule Raddi, 1823 |
| Panicum compressum Balb. ex Steud., 1841 |
| Panicum conchatum E. Fourn., 1886 |