| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| MALI4 | Machaeranthera linearis Greene | Machaeranthera canescens ssp. glabra var. glabra | Asteraceae
|
| MALI | Machaeranthera linearis Rydb., non Greene | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MAMA23 | Machaeranthera magna A. Nels. | Machaeranthera canescens ssp. canescens var. sessiliflora | Asteraceae
|
| MAME4 | Machaeranthera mexicana B.L. Turner & Horne | Psilactis gentryi | Asteraceae
|
| MAMO5 | Machaeranthera montana Greene | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MAMU | Machaeranthera mucronata Greene | Machaeranthera bigelovii var. mucronata | Asteraceae
|
| MAOR8 | Machaeranthera orcuttii (Vasey & Rose) Cronq. & Keck | Xylorhiza orcuttii | Asteraceae
|
| MAOX | Machaeranthera oxylepis Greene | Machaeranthera canescens ssp. canescens var. ambigua | Asteraceae
|
| MAPA19 | Machaeranthera paniculata A. Nels. | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MAPA11 | Machaeranthera parthenium Greene | Machaeranthera tanacetifolia | Asteraceae
|
| MAPA | Machaeranthera parviflora Gray | smallflower tansyaster | Asteraceae
|
| MAPA10 | Machaeranthera pattersonii (Gray) Greene | Machaeranthera bigelovii var. bigelovii | Asteraceae
|
| MAPHM | Machaeranthera phyllocephala (DC.) Shinners var. megacephala (Nash) Shinners | Rayjacksonia phyllocephala | Asteraceae
|
| MAPH2 | Machaeranthera phyllocephala (DC.) Shinners | Rayjacksonia phyllocephala | Asteraceae
|
| MAPI5 | Machaeranthera pinnata (Nutt.) Shinners | Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida | Asteraceae
|
| MAPIG2 | Machaeranthera pinnatifida (Hook.) Shinners ssp. gooddingii (A. Nels.) B.L. Turner & Hartman var. gooddingii | Goodding's tansyaster | Asteraceae
|
| MAPIP3 | Machaeranthera pinnatifida (Hook.) Shinners ssp. gooddingii (A. Nels.) B.L. Turner & Hartman var. paradoxa B.L. Turner & Hartman | Goodding's tansyaster | Asteraceae
|
| MAPIG | Machaeranthera pinnatifida (Hook.) Shinners ssp. gooddingii (A. Nels.) B.L. Turner & Hartman | Goodding's tansyaster | Asteraceae
|
| MAPIC | Machaeranthera pinnatifida (Hook.) Shinners ssp. pinnatifida var. chihuahuana B.L. Turner & Hartman | Chihuahua tansyaster | Asteraceae
|
| MAPIG3 | Machaeranthera pinnatifida (Hook.) Shinners ssp. pinnatifida var. glaberrima (Rydb.) B.L. Turner & Hartman | lacy tansyaster | Asteraceae
|
| MAPIP4 | Machaeranthera pinnatifida (Hook.) Shinners ssp. pinnatifida var. pinnatifida | lacy tansyaster | Asteraceae
|
| MAPIP | Machaeranthera pinnatifida (Hook.) Shinners ssp. pinnatifida | lacy tansyaster | Asteraceae
|
| MAPIS | Machaeranthera pinnatifida (Hook.) Shinners var. scabrella (Greene) Turner & Hartman | machaeranthera | Asteraceae
|
| MAPI | Machaeranthera pinnatifida (Hook.) Shinners | lacy tansyaster | Asteraceae
|
| MAPI4 | Machaeranthera pinosa Elmer | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MAPR6 | Machaeranthera pruinosa Gray | Psilactis asteroides | Asteraceae
|
| MAPUV | Machaeranthera pulverulenta (Nutt.) Greene var. vacans A. Nels. | Machaeranthera canescens ssp. glabra var. aristata | Asteraceae
|
| MAPU8 | Machaeranthera pulverulenta (Nutt.) Greene | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MAPY2 | Machaeranthera pygmaea (Gray) Woot. & Standl. | Machaeranthera parviflora | Asteraceae
|
| MARA8 | Machaeranthera ramosa A. Nels. | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MARI2 | Machaeranthera rigida Greene | Machaeranthera canescens ssp. glabra var. aristata | Asteraceae
|
| MARI | Machaeranthera riparia (Kunth) A.G. Jones | Chiricahua Mountain tansyaster | Asteraceae
|
| MARU3 | Machaeranthera rubricaulis Rydb. | Machaeranthera bigelovii var. bigelovii | Asteraceae
|
| MASC2 | Machaeranthera scoparia Greene | Machaeranthera canescens ssp. canescens var. ambigua | Asteraceae
|
| MASE4 | Machaeranthera selbyi Rydb. | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MASE2 | Machaeranthera sessiliflora (Nutt.) Greene | Machaeranthera canescens ssp. canescens var. sessiliflora | Asteraceae
|
| MASHE | Machaeranthera shastensis Gray var. eradiata (Gray) Cronq. & Keck | Machaeranthera canescens ssp. canescens var. shastensis | Asteraceae
|
| MASHG | Machaeranthera shastensis Gray var. glossophylla (Piper) Cronq. & Keck | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MASHL | Machaeranthera shastensis Gray var. latifolia (Cronq.) Cronq. & Keck | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MASHM | Machaeranthera shastensis Gray var. montana (Greene) Cronq. & Keck | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MASH | Machaeranthera shastensis Gray | Machaeranthera canescens ssp. canescens var. shastensis | Asteraceae
|
| MASI7 | Machaeranthera simplex Woot. & Standl. | Psilactis asteroides | Asteraceae
|
| MASO7 | Machaeranthera sonorae (Gray) J. Stucky | Machaeranthera riparia | Asteraceae
|
| MASP4 | Machaeranthera spinulosa (Greene) Cory, non Amellus spinulosa Pursh | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MASU3 | Machaeranthera subalpina Greene | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MASU6 | Machaeranthera superba A. Nels. | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MATA | Machaeranthera tagetina Greene | mesa tansyaster | Asteraceae
|
| MATA2 | Machaeranthera tanacetifolia (Kunth) Nees | tanseyleaf tansyaster | Asteraceae
|
| MATE11 | Machaeranthera tenuis (S. Wats.) B.L. Turner & Horne | Psilactis tenuis | Asteraceae
|
| MATE | Machaeranthera tephrodes (Gray) Greene | Machaeranthera canescens ssp. canescens var. incana | Asteraceae
|
| MATE12 | Machaeranthera texensis (R.C. Jackson) Shinners | Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida | Asteraceae
|
| MATOI | Machaeranthera tortifolia (Torr. & Gray) Cronq. & Keck var. imberbis Cronq. | Xylorhiza tortifolia var. imberbis | Asteraceae
|
| MATO4 | Machaeranthera tortifolia (Torr. & Gray) Cronq. & Keck | Xylorhiza tortifolia var. tortifolia | Asteraceae
|
| MAVE4 | Machaeranthera venusta (M.E. Jones) Cronq. & Keck | Xylorhiza venusta | Asteraceae
|
| MAVE3 | Machaeranthera verna A. Nels. | Psilactis asteroides | Asteraceae
|
| MAVI9 | Machaeranthera viscida (Woot. & Standl.) R.L. Hartman | sticky tansyaster | Asteraceae
|
| MAVI7 | Machaeranthera viscosa (Nutt.) Greene | Machaeranthera canescens ssp. canescens var. canescens | Asteraceae
|
| MAWR4 | Machaeranthera wrightii (Gray) Cronq. & Keck | Xylorhiza wrightii | Asteraceae
|
| MACHA | Machaeranthera Nees | tansyaster | Asteraceae
|
| MAAN | Machaerina angustifolia (Gaud.) T. Koyama | Polynesian twigrush | Cyperaceae
|
| MAFA9 | Machaerina falcata (Nees) Koyama | twigrush | Cyperaceae
|
| MAGA | Machaerina gahniiformis (Gaud.) J. Kern | Gahnia gahniiformis | Cyperaceae
|
| MAMAM | Machaerina mariscoides (Gaud.) J. Kern ssp. meyenii (Kunth) T. Koyama | Meyen's twigrush | Cyperaceae
|
| MAMA12 | Machaerina mariscoides (Gaud.) J. Kern | tropical twigrush | Cyperaceae
|
| MARE2 | Machaerina restioides (Sw.) Vahl | forest twigrush | Cyperaceae
|
| MACHA2 | Machaerina Vahl | twigrush | Cyperaceae
|
| MALU2 | Machaerium lunatum (L. f.) Ducke | palo de hoz | Fabaceae
|
| MACHA4 | Machaerium Pers. | machaerium | Fabaceae
|
| MACA3 | Machaerocarpus californicus (Torr. ex Benth.) Small | Damasonium californicum | Alismataceae
|
| MAPO6 | Machaonia portoricensis Baill. | | Rubiaceae
|
| MAWO3 | Machaonia woodburyana Acev.-Rodr. | alfilerillo | Rubiaceae
|
| MACHA5 | Machaonia Humb. & Bonpl. | machaonia | Rubiaceae
|
| MACO10 | Macleaya cordata (Willd.) R. Br. | plume poppy | Papaveraceae
|
| MACLE | Macleaya R. Br. | macleaya | Papaveraceae
|
| MAPO | Maclura pomifera (Raf.) Schneid. | osage orange | Moraceae
|
| MATI3 | Maclura tinctoria (L.) D. Don ex Steud. | fustictree | Moraceae
|
| MACLU | Maclura Nutt. | maclura | Moraceae
|
| MAIS | Macounastrum islandicum (L.) Small | Koenigia islandica | Polygonaceae
|
| MALU | Macradenia lutescens R. Br. | longgland orchid | Orchidaceae
|
| MACRA | Macradenia R. Br. | macradenia | Orchidaceae
|
| MAFL4 | Macranthera flammea (Bartr.) Pennell | flameflower | Scrophulariaceae
|
| MACRA2 | Macranthera Nutt. ex Benth. | macranthera | Scrophulariaceae
|
| MACA27 | Macrocnemum candidissimum Vahl | Calycophyllum candidissimum | Rubiaceae
|
| MAHY3 | Macrocoma hymenostomum sensu Grout | Macrocoma sullivantii | Orthotrichaceae
|
| MASU5 | Macrocoma sullivantii (C. M�ll.) Grout | Sullivant's macrocoma moss | Orthotrichaceae
|
| MATES | Macrocoma tenue (Hook. & Grev.) Vitt ssp. sullivantii (C. M�ll.) Vitt | Macrocoma sullivantii | Orthotrichaceae
|
| MACRO6 | Macrocoma (Hornsch. ex C. M�ll.) Grout | macrocoma moss | Orthotrichaceae
|
| MAVIT | Macromeria viridiflora DC. var. thurberi (Gray) I.M. Johnston | Thurber's giant-trumpets | Boraginaceae
|
| MAVIV | Macromeria viridiflora DC. var. viridiflora | giant-trumpets | Boraginaceae
|
| MAVI | Macromeria viridiflora DC. | giant-trumpets | Boraginaceae
|
| MACRO | Macromeria D. Don | giant-trumpets | Boraginaceae
|
| MARH | Macromitrium rhabdocarpum Mitt. | Macromitrium richardii | Orthotrichaceae
|
| MARI3 | Macromitrium richardii Schwaegr. | Richard's macromitrium moss | Orthotrichaceae
|
| MASU12 | Macromitrium sullivantii C. M�ll. | Macrocoma sullivantii | Orthotrichaceae
|
| MACRO7 | Macromitrium Brid. | macromitrium moss | Orthotrichaceae
|
| MAAB3 | Macronema aberrans A. Nels. | Tonestus aberrans | Asteraceae
|
| MADI9 | Macronema discoidea Nutt. | Ericameria discoidea var. discoidea | Asteraceae
|
| MAGR12 | Macronema greenei (Gray) Greene | Ericameria greenei | Asteraceae
|
| MALIC | Macronema lineare Rydb. var. canescens A. Nels. | Ericameria discoidea var. linearis | Asteraceae
|
| MALI3 | Macronema lineare Rydb. | Ericameria discoidea var. linearis | Asteraceae
|
| MAOB4 | Macronema obovatum Rydb., non Haplopappus obovatus Phil. | Ericameria obovata | Asteraceae
|