Weed Herbarium – by Scientific Name
| Maianthemum canadense | false lily-of-the-valley | Liliaceae - Lily Family |
| Malva neglecta | common mallow | Malvaceae - Mallow Family |
| Marchantia polymorpha | liverwort | Phylum: Hepatophyta |
| Matricaria matricariodes | pineappleweed | Asteraceae (Compositae) - Aster or Sunflower Family |
| Medicago lupulina | black medic | Fabaceae (Leguminosae) - Pea or Bean Family |
| Melilotus alba | white sweet clover | Fabaceae (Leguminosae) - Pea or Bean Family |
| Melilotus officinalis | yellow sweet clover | Fabaceae (Leguminosae) - Pea or Bean Family |
| Microstegium vimineum | Japanese stiltgrass | Poaceae (Graminae) - Grass Family |
| Mimulus alatus | sharp-winged monkey-flower | Scrophulariaceae - Figwort Family |
| Mirabilis nyctaginea | wild four-o'-clock | Nyctaginaceae - Four-O'clock Family |
| Miscanthus sacchariflorus | amur silvergrass | Poaceae (Graminae) - Grass Family |
| Mollugo verticillata | carpetweed | Aizoaceae - Carpetweed Family |
| Muhlenbergia schreberi | wiregrass nimblewill | Poaceae (Graminae) - Grass Family |
| Myrrhis claytonia | see - Osmorhiza claytoni | |
| Myrrhis longistylis | see - Osmorhiza longistilis |