| Macaranga capensis | Mallota capensis, Mappa capensis | 
| Mackaya bella | Asystasia bella | 
| Mackfadyena unguis-cati | Doxanthus unguis-cati, Bignonia tweediana | 
| Maclura pomifera | Maclura aurantiaca, Toxylon pomifera | 
| Macrozamia miquelii | Encephalartos miquelii, Macrozamia mackenzii | 
| Maerua edulis | Courbonia edulis | 
| Magnolia coco | Magnolia pumila,  Michelia coco,  Michelia pumila | 
| Malpighia glabra | Malpighia punicifolia, Malpighia uniflora | 
| Malvaviscus arboreus var. drummondii | Malvaviscus drummondii | 
| Mandevilla suaveolens | Amblyanthera suaveolens, Echites suaveolens, Mandevilla laxa | 
| Manfreda virginica | Agave virginica, Polianthes virginica | 
| Mangifera indica | Mangifera domestica, Mangifera sativa | 
| Manilkara discolor | Labourdonnaisia discolor, Muriea discolor | 
| Mansoa alliacea | Pseudocalymma alliacea, Adenocalymma alliaceum, Bignonia alliacea u.a. | 
| Mansoa difficilis | Bignonia difficilis, Adenocalymma splendens | 
| Marah macrocarpus | Marah macrocarpa, Echinocystis macrocarpa, Marah major, Marah micranthus, Megarrhiza macrocarpa, Micrampelis macrocarpa, Echinocystis macrocarpa | 
| Markhamia hildebrandtii | Markhamia lutea, Markhamia platycalyx | 
| Marlothistella stenophylla | Mesembryanthemum stenophyllum | 
| Massonia depressa | Massonia latifolia | 
| Melia azedarach | Melia japonica, Melia sempervirens | 
| Melicope elleryana | Euodia elleryana, Evodia elleryana | 
| Merremia dissecta | Convolvulus dissectus,  Ipomoea dissecta, Ipomoea sinuata, Operculina dissecta | 
| Merremia tuberosa | Ipomoea tuberosa | 
| Merremia umbellata | Convolvulus umbellatus | 
| Mertensia virginica | Mertensia pulmonarioides | 
| Metrosideros excelsa | Metrosideros tomentosa | 
| Michelia champaca | Michelia rheedii, Michelia avrantiaca | 
| Michelia figo | Michelia fuscata | 
| Mimosa dysocarpa | Mimosa wrightii | 
| Mimosa hostilis | Mimosa tenuiflora, Acacia tenuiflora, Mimosa cabrera | 
| Mina lobata | Ipomoea lobata, Urena lobata | 
| Mirabilis jalapa | Mirabilis lindheimeri, Mirabilis dichotoma, Mirabilis odorata | 
| Mirabilis viscosa | Oxybaphus viscosus | 
| Mirbelia dilatata | Mirbelia meisneri | 
| Monanthotaxis caffra | Guatteria caffra, Popowia caffra | 
| Monstera deliciosa | Philodendron pertusum | 
| Moraea bicolor | Dietes bicolor | 
| Morella brevifolia | Myrica brevifolia | 
| Moringa oleifera | Moringa pterygosperma, Moringa moringa, Guilandina moringa | 
| Morrenia odorata | Cynanchum odoratum | 
| Mucuna deeringiana | Mucuna pruriens var. utilis | 
| Mucuna pruriens | Dolichos pruriens | 
| Mundulea sericea | Mundulea suberosa | 
| Murraya koenigii | Bergera koenigii, Chalcas koenigii | 
| Murraya paniculata | Murraya exotica, Chalcas paniculata, Chalcas exotica | 
| Musa ensete | Ensete ventricosum | 
| Musa glauca | Ensete glaucum | 
| Musa hookeri | Musa sikkimensis | 
| Myrciaria cauliflora | Plinia cauliflora, Eugenia cauliflora | 
| Myrica cerifera | Myrica carolinensis, Myrica pusilla, Myrica mexicana, Morella cerifera, Cerothamnus cerifera, Cerothamnus Pumilus |