| Panicum leucophaeum Kunth, 1815 |
| Panicum leucothrix Nash, 1897 |
| Panicum liebmannianum E. Fourn., 1886 |
| Panicum liebmannianum var. depauperatum E. Fourn., 1886 |
| Panicum liebmannianum var. liebmannianum E. Fourn., 1886 |
| Panicum lindenii Griseb., 1866 |
| Panicum linkianum Kunth, 1829 |
| Panicum littorale Mohr ex Vasey, 1879 |
| Panicum loliaceum Lam., 1791 |
| Panicum longepaniculatum Benoist, 1950 |
| Panicum longiculme Swallen, 1931 |
| Panicum longiligulatum Nash, 1899 |
| Panicum longipedunculatum Scribn., 1894 |
| Panicum longisetum Torr., 1822 |
| Panicum longum Hitchc. & Chase, 1910 |
| Panicum lucidum Ashe, 1898 |
| Panicum lucidum var. opacum Fernald, 1937 |
| Panicum lundellii Swallen, 1938 |
| Panicum lutescens Weigel, 1772 |
| Panicum lutescens var. flavum (Nees) Backer, 1927 |