| Abbreviation | Definition |
|---|---|
| MBBG | Manhattan Beach Botanical Garden |
| MBG | Matthaei Botanical Gardens |
| MBG | Missouri Botanical Garden |
| MC | Moisture Content |
| MCBG | Mendocino Coast Botanical Gardens |
| MCPA | 2-methyl-4-chlorophenoxy acetic acid |
| MCS | Moisture Control System |
| MEPS | Molecular and Environmental Plant Sciences |
| MFP | Moisture and Fungus Proofed |
| MG | Morning Glory |
| MH | Maleic Acid |
| MIS | Management Indicator Species |
| MISC | Maui Invasive Species Committee |
| MIST | Mitochondria Investigation and Suppresion Team |
| MLO | Mildew-resistance LOcus gene |
| MM | Merton Malling |
| MMRC | Mensuration and Modelling Research Consortium |
| MOG | Mandai Orchid Garden |
| MOSS | Microwave Observatory of Subcanopy and Subsurface |
| MP | Money Plant |