| Lappula pustulata J.F. Macbr., 1916 |
| Lappula redowskii (Hornem.) Greene, 1891 |
| Lappula redowskii var. desertorum (Greene) I.M. Johnst., 1932 |
| Lappula redowskii var. occidentalis (S. Watson) Á. Löve & D. Löve, 1982 |
| Lappula texana (Scheele) Britton, 1894 |
| Lappula texana var. coronata (Greene) A. Nelson & J.F. Macbr., 1916 |
| Lasiarrhenum I.M. Johnst., 1924 |
| Lasiarrhenum confundum B.L. Turner, 1994 |
| Lasiarrhenum lundellii I.M. Johnst., 1959 |
| Lasiarrhenum pinetorum I.M. Johnst., 1935 |
| Lasiarrhenum strigosum I.M. Johnst., 1924 |
| Lasiarrhenum trinervium (Lehm.) B.L. Turner, 1994 |
| Lithospermeae Dumort., 1827 |
| Lithospermum L., 1753 |
| Lithospermum album (G.L. Nesom) J.I. Cohen, 2009 |
| Lithospermum altamiranense Pat.-Sicil., J.I. Cohen & Pérez-Calix, 2019 |
| Lithospermum angustifolium Sessé & Moc., 1893 |
| Lithospermum approximatum Brand, 1930 |
| Lithospermum arvense L., 1753 |
| Lithospermum asteinzae Pat.-Sicil., J.I. Cohen & Pérez-Calix, 2019 |