| Lagerstroemia speciosa | Lagerstroemia flos-reginae |
| Lagunaria patersonii | Hibiscus patersonii |
| Larrea tridentata | Larrea divaricatum subs. tridentata, Zygophyllum tridentatum, Covillea tridentata, Schroeterella tridentata, Neoschroetera tridentata, Larrea glutinosa |
| Lawsonia inermis | Lawsonia alba |
| Leonotis leonurus | Phlomis leonurus |
| Leptospermum lanigerum | Leptospermum pubescens |
| Leptospermum scoparium | Leptospermum floribundum |
| Lespedeza bicolor | Desmodium bicolor |
| Lespedeza thunbergii | Lespedeza formosa |
| Lessertia frutescens | Sutherlandia frutescens |
| Leucaena leucocephala | Leucaena glauca, Mimosa leucocephala, Acacia leucocephala |
| Libertia formosa | Libertia chilensis |
| Liparia splendens | Liparia sphaerica |
| Liquidambar formosana | Liquidambar maximowiczii, Liqiudambar tonkinensis |
| Lophostemon confertus | Tristania conferta |
| Luculia gratissima | Chinchona gratissima |
| Luffa acutangula | Luffa foetida |
| Luffa cylindrica | Luffa aegyptica |