- Maculate
- Male flower
- Malesia
- Mammillose
- Massula
- Medial
- Median
- Membranous
- Mentum
- Mesochilium
- Midrib
- Mobile
- Monandrous
- Moniliform
- Monoecious
- Monophyletic
- Monopodial
- Monothetic group
- Monotypic
- Monstrosity
- Mucose
- Mucro
- Mucronate
- Mucronulate
- Muricate
- Muriculate
- Mycoparasite
- Mycorrhiza
- Mycotrophic
- Myrmecophyte