| Laphamia lemmonii A. Gray, 1880 |
| Laphamia lemmonii var. pedata A. Gray, 1880 |
| Laphamia leptoglossa (Harv. & Gray ex A. Gray) Lichter-Marck, 2022 |
| Laphamia lloydii (B.L. Rob. & Fernald) Lichter-Marck, 2022 |
| Laphamia lobata (Rydb.) Lichter-Marck, 2022 |
| Laphamia parryi (A. Gray) Benth. & Hook. f., 1873 |
| Laphamia reinana (B.L. Turner) Lichter-Marck, 2022 |
| Laphamia sanchezii Lichter-Marck, 2022 |
| Laphamia scopulorum M.E. Jones, 1908 |
| Laphamia vandevenderi (B.L. Turner) Lichter-Marck, 2022 |
| Laphamia vaseyi (J.M. Coult.) Lichter-Marck, 2022 |
| Laphangium (Hilliard & B.L. Burtt) Tzvelev, 1994 |
| Laphangium luteoalbum (L.) Tzvelev, 1994 |
| Lapsana L., 1753 |
| Lapsana communis L., 1753 |
| Lasallea Greene, 1903 |
| Lasallea oblongifolia (Nutt.) Semple & Brouillet, 1980 |
| Lasianthaea DC., 1836 |
| Lasianthaea aurea (D. Don) K.M. Becker, 1979 |
| Lasianthaea beckeri B.L. Turner, 1988 |