| Larrea watsonii (Fisher) Britton, 1930 |
| Larrea wootonii Britton, 1930 |
| Lathyrus L., 1753 |
| Lathyrus alefeldii T.G. White, 1894 |
| Lathyrus americanus Mill., 1768 |
| Lathyrus arizonicus Britton, 1889 |
| Lathyrus arvensis Phil., 1856 |
| Lathyrus brachycalyx Rydb., 1907 |
| Lathyrus brachycalyx subsp. eucosmus (Butters & H. St. John) S.L. Welsh, 1966 |
| Lathyrus brachycalyx var. eucosmus (Butters & H. St. John) S.L. Welsh, 1978 |
| Lathyrus crassipes Gillies ex Hook. & Arn., 1833 |
| Lathyrus dicirrhus Clos, 1847 |
| Lathyrus diffusus G. Don, 1832 |
| Lathyrus dissitifolius Nutt. ex Torr. & A. Gray, 1838 |
| Lathyrus engelmanni Bisch., 1839 |
| Lathyrus eucosmus Butters & H. St. John, 1917 |
| Lathyrus graminifolius (S. Watson) T.G. White, 1894 |
| Lathyrus guaraniticus Hassl., 1919 |
| Lathyrus laetiflorus Greene, 1893 |
| Lathyrus laetiflorus subsp. alefeldii (T.G. White) Bradshaw, 1925 |