| Macrachaenium |
gracile |
| Macropharynx |
meyeri |
| Macroptilium |
arenarium |
| Magallana |
porifolia, trialata |
| Maihueniopsis |
darwinii, minuta, ovata, recurvata |
| Malaxis |
padilliana |
| Malvastrum |
uniapiculatum |
| Mancoa |
venturii |
| Mandevilla |
grata |
| Manettia |
jorgensenii |
| Marsdenia |
tressensiae |
| Mastigostyla |
brachiandra, cabrerae, implicata, johnstoni, mirabilis |
| Matelea |
argentinensis, calchaquina, fiebrigii , hispida, schreiteri |
| Maytenus |
cuezzoi, spinosa, viscifolia |
| Mecardonia |
kamogawae |
| Melica |
bonariensis, glabrescens, lilloi, parodiana, patagonica |
| Melinia |
candolleana, micrantha, tubata, volcanense |
| Melosperma |
angustifolia |
| Menodora |
robusta |
| Menonvillea |
alyssoides, comberi, famatinensis, patagonica, rigida, scapigera, spathulata, zuloagaensis |
| Mesosetum |
comatum |
| Metastelma |
microgynostegia, oranensis, tubatum |
| Micranthemum |
tweediei |
| Microgyne |
trifurcata |
| Microgynella |
trifurcata |
| Microliabum |
candidum, eremophilum , humile |
| Micropsis |
australis, ostenii, spathulata |
| Mikania |
jujuyensis, minima, siambonensis, summinima |
| Mimosa |
cordobensis, ephedroides, longiracemosa, ostenii |
| Minthostachys |
verticillata |
| Mitostigma |
affine, barbatum, castillonii, caudatum, lilloi, mitophorum, niveum, subniveum, tucumanense |
| Modiolastrum |
australe |
| Monanthochloe |
acerosa |
| Monnina |
lorentziana |
| Monttea |
aphylla, schickendantzii |
| Monvillea |
krapovickiana |
| Morrenia |
intermedia, scalae |
| Moschopsis |
ameghinoi, caleofuensis, leyboldii, rosulata, trilobata |
| Mostacillastrum |
ameghinoi, carolinense, hunzikeri, saltaensis, stenophyllum , subscandens , ventanense |
| Moya |
spinosa |
| Muhlenbergia |
angustata (J. Presl) Kunth x M. rigida, holwayorum |
| Mulinum |
axilliflorum, echegarayii, echinus, famatinense, hallei, microphyllum, valentini |
| Munroa |
mendocina |
| Mutisia |
burkartii, castellanosii, kurtzii, linifolia, retrorsa, saltensis |
| Myrcianthes |
callicoma |
