| Magnoliopsida | EUKARYA>ARCHAEPLASTIDA>VIRIDIPLANTAE>STREPTOBIONTA>EMBRYOPHYTA>TRACHEOPHYTA>SPERMOPHYTA>ANGIOSPERMOPHYTA>MAGNOLIOPSIDA |
| Mammalia | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>BILATERIA>DEUTEROSTOMATA>VERTEBRATA>GNATHOSTOMATA>TETRAPODA>AMNIOTA>SYNAPSIDA>MAMMALIA |
| Mandibulata | see Arthropoda |
| Marattiopsida | see Pteridophyta |
| Marchantiophyta | EUKARYA>ARCHAEPLASTIDA>VIRIDIPLANTAE>STREPTOBIONTA>EMBRYOPHYTA>MARCHANTIOPHYTA |
| Marchantiopsida | see Marchantiophyta |
| Medullosopsida | see Pteridospermophyta |
| Mesostigmatophyceae | see Charophyta |
| Mesozoa | see Spiralia |
| Metamonada | EUKARYA>EXCAVATA>EUEXCAVATA>METAMONADA |
| Metarhodophytina | see Rhodophyta |
| Metazoa | see Animalia |
| Metchnikovellomycetes | see Microsporidia |
| Methanobacteria | ARCHAEA>EURYARCHAEOTA>METHANOBACTERIA |
| Micrognathozoa | see Spiralia |
| Microsporidia | EUKARYA>OPISTHOKONTA>UNIKONTA>FUNGI>BASAL FUNGI>MICROSPORIDIA |
| Microsporomycetes | see Microsporidia |
| Mollusca | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>METAZOA>BILATERIA>PROTOSTOMATA>SPIRALIA>TROCHOZOA>EUTROCHOZOA>MOLLUSCA |
| Monoblepharomycetes | see Chytridiomycota |
| Mortierellomycetes | see Chytridiomycota |
| Mucoromycetes | see Mucoromycota |
| Mucoromycota | EUKARYA>OPISTHOKONTA>UNIKONTA>FUNGI>BASAL FUNGI>MUCOROMYCOTA |
| Myriapoda | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>BILATERIA>PROTOSTOMATA>ECDYSOZOA>PANARTHROPODA>ARTHROPODA>MYRIAPODA |
| Myxinomorphi | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>BILATERIA>DEUTEROSTOMATA>VERTEBRATA>MYXINOMORPHI |
| Myxozoa | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>RADIATA>MYXOZOA |
