Weed Herbarium – by Scientific Name
| Lactuca scariola | see - Lactuca serriola | |
| Lactuca biennis | biennial lettuce | Asteraceae (Compositae) - Aster or Sunflower Family |
| Lactuca canadensis | tall lettuce | Asteraceae (Compositae) - Aster or Sunflower Family |
| Lactuca serriola | prickly lettuce | Asteraceae (Compositae) - Aster or Sunflower Family |
| Lamium amplexicaule | henbit | Lamiaceae (Labiatae) - Mint Family |
| Lamium purpureum | red deadnettle | Lamiaceae (Labiatae) - Mint Family |
| Lapsana communis | nipplewort | Asteraceae (Compositae) - Aster or Sunflower Family |
| Lathyrus latifolius | everlasting peavine | Fabaceae (Leguminosae) - Pea or Bean Family |
| Leontodon autumnalis | fall dandelion | Asteraceae (Compositae) - Aster or Sunflower Family |
| Leonurus cardiaca | motherwort | Lamiaceae (Labiatae) - Mint Family |
| Lepidium campestre | field pepperweed | Brassicaceae (Cruciferae) - Mustard Family |
| Lepidium virginicum | Virginia pepperweed | Brassicaceae (Cruciferae) - Mustard Family |
| Lespedeza virginica | slender bush clover | Fabaceae (Leguminosae) - Pea or Bean Family |
| Leucanthemum leucanthemum | see - Chrysanthemum leucanthemum |
| Linaria cymbalaria | see - Cymbalaria muralis | |
| Linaria canadensis | old field toadflax | Scrophulariaceae - Figwort Family |
| Linaria vulgaris | yellow toadflax | Scrophulariaceae - Figwort Family |
| Lobelia syphilitica | see - Lobelia siphilitica | |
| Lobelia inflata | Indian tobacco | Lobeliaceae - Bluebell Family |
| Lobelia siphilitica | great lobelia | Lobeliaceae - Bluebell Family |
| Lonicera japonica | Japanese honeysuckle | Caprifoliaceae - Honeysuckle Family |
| Lotus corniculatus | birdfoot trefoil | Fabaceae (Leguminosae) - Pea or Bean Family |
| Lychnis flos-cuculi | ragged robin | Caryophyllaceae - Pink Family |
| Lycopus americanus | american bugleweed | Lamiaceae (Labiatae) - Mint Family |
| Lysimachia ciliata | fringed loosestrife | Primulaceae - Primrose Family |
| Lysimachia nummularia | moneywort | Primulaceae - Primrose Family |
| Lythrum salicaria | purple loosestrife | Lythraceae - Loosestrife Family |