| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| MUFL | Mulgedium floridanum (L.) DC. | Lactuca floridana var. floridana | Asteraceae
|
| MUSPI | Mulgedium spicatum (Lam.) Small var. integrifolium (Torr. & Gray) Small | Lactuca biennis | Asteraceae
|
| MUSP2 | Mulgedium spicatum auct. non (Lam.) Small | Lactuca biennis | Asteraceae
|
| MUVI3 | Mulgedium villosum (Jacq.) Small | Lactuca floridana var. villosa | Asteraceae
|
| MUCO6 | Multiclavula coronilla (G. W. Martin) R. Petersen | club lichen | Clavariaceae
|
| MUCO7 | Multiclavula corynoides (Peck) R. Petersen | club lichen | Clavariaceae
|
| MUMU4 | Multiclavula mucida (Fr.) R. Petersen | club lichen | Clavariaceae
|
| MUSH | Multiclavula sharpii R. Petersen | Sharp's club lichen | Clavariaceae
|
| MUVE2 | Multiclavula vernalis (Schwein.) R. Petersen | spring club lichen | Clavariaceae
|
| MULTI | Multiclavula R. Petersen | club lichen | Clavariaceae
|
| MURAF | Munroidendron racemosum (Forbes) Sherff var. forbesii Sherff | Munroidendron racemosum | Araliaceae
|
| MURAM | Munroidendron racemosum (Forbes) Sherff var. macdanielsii Sherff | Munroidendron racemosum | Araliaceae
|
| MURA3 | Munroidendron racemosum (Forbes) Sherff | false 'ohe | Araliaceae
|
| MUNRO2 | Munroidendron Sherff | munroidendron | Araliaceae
|
| MUCA4 | Muntingia calabura L. | strawberrytree | Elaeocarpaceae
|
| MUNTI | Muntingia L. | muntingia | Elaeocarpaceae
|
| MUBL | Munzothamnus blairii (Munz & Johnston) Raven | Stephanomeria blairii | Asteraceae
|
| MUKE | Murdannia keisak (Hassk.) Hand.-Maz. | wartremoving herb | Commelinaceae
|
| MUNU | Murdannia nudiflora (L.) Brenan | nakedstem dewflower | Commelinaceae
|
| MUSI3 | Murdannia simplex (Vahl) Brenan | | Commelinaceae
|
| MUSP | Murdannia spirata (L.) Bruckner | Asiatic dewflower | Commelinaceae
|
| MURDA | Murdannia Royle | murdannia | Commelinaceae
|
| MUDR | Muricauda dracontium (L.) Small | Arisaema dracontium | Araceae
|
| MUEX2 | Murraya exotica L. | Chinese box | Rutaceae
|
| MUKO | Murraya koenigii (L.) Sprengel | curryleaftree | Rutaceae
|
| MUPA4 | Murraya paniculata auct. non (L.) Jack | Murraya exotica | Rutaceae
|
| MURRA | Murraya Koenig ex L. | murraya | Rutaceae
|
| MUAC | Musa acuminata Colla | edible banana | Musaceae
|
| MUBA | Musa balbisiana Colla | banana | Musaceae
|
| MUCA5 | Musa cavendishii Lamb. ex Paxton | Musa acuminata | Musaceae
|
| MUCH | Musa chinensis Lamb. ex Paxton | Musa acuminata | Musaceae
|
| MUEN | Musa ensete Gmelin | Ensete ventricosum | Musaceae
|
| MUORN | Musa ornata Roxb. var. normalis Kuntze | Musa paradisiaca | Musaceae
|
| MUPA3 | Musa �paradisiaca L. (pro sp.) | French plantain | Musaceae
|
| MUSA | Musa sapientum L. | Musa paradisiaca | Musaceae
|
| MUTE6 | Musa textilis Nee | abaca | Musaceae
|
| MUTR2 | Musa troglodytarum L. | fe'i banana | Musaceae
|
| MUVE | Musa velutina H. Wendl. & Drude | hairy banana | Musaceae
|
| MUZE | Musa zebrina Van Houtte ex Planch. | Musa acuminata | Musaceae
|
| MUSA2 | Musa L. | banana | Musaceae
|
| MUMU3 | Muscadinia munsoniana (Simpson ex Munson) Small | Vitis rotundifolia var. munsoniana | Vitaceae
|
| MURO | Muscadinia rotundifolia (Michx.) Small | Vitis rotundifolia var. rotundifolia | Vitaceae
|
| MUAR5 | Muscari armeniacum Leichtl. ex Baker | Armenian grape hyacinth | Liliaceae
|
| MUAT | Muscari atlanticum Boiss. & Reut. | Muscari neglectum | Liliaceae
|
| MUBO | Muscari botryoides (L.) P. Mill. | common grape hyacinth | Liliaceae
|
| MUCO2 | Muscari comosum (L.) P. Mill. | tassel grape hyacinth | Liliaceae
|
| MUNE | Muscari neglectum Guss. ex Ten. | starch grape hyacinth | Liliaceae
|
| MURA2 | Muscari racemosum (L.) Lam. & DC. | Muscari neglectum | Liliaceae
|
| MUSCA | Muscari P. Mill. | grape hyacinth | Liliaceae
|
| MUAD | Muscaria adscendens (L.) Small p.p. | Saxifraga adscendens ssp. oregonensis | Saxifragaceae
|
| MUCA6 | Muscaria caespitosa (L.) Haw. | Saxifraga caespitosa ssp. caespitosa | Saxifragaceae
|
| MUCE | Muscaria cespitosa (L.) Haw. [orthographic variant] | Saxifraga caespitosa ssp. caespitosa | Saxifragaceae
|
| MUDE4 | Muscaria delicatula Small | Saxifraga caespitosa ssp. delicatula | Saxifragaceae
|
| MUMI3 | Muscaria micropetala Small | Saxifraga caespitosa ssp. monticola | Saxifragaceae
|
| MUMO3 | Muscaria monticola Small | Saxifraga caespitosa ssp. monticola | Saxifragaceae
|
| MUDID | Musineon divaricatum (Pursh) Raf. var. divaricatum | leafy wildparsley | Apiaceae
|
| MUDIH | Musineon divaricatum (Pursh) Raf. var. hookeri (Torr. & Gray) Mathias | Hooker's wildparsley | Apiaceae
|
| MUDI | Musineon divaricatum (Pursh) Raf. | leafy wildparsley | Apiaceae
|
| MUHO | Musineon hookeri (Torr. & Gray) Nutt. | Musineon divaricatum var. hookeri | Apiaceae
|
| MULI2 | Musineon lineare (Rydb.) Mathias | narrowleaf wildparsley | Apiaceae
|
| MUTE3 | Musineon tenuifolium (Nutt. ex Torr. & Gray) Coult. & Rose | slender wildparsley | Apiaceae
|
| MUTR3 | Musineon trachyspermum Nutt. | Musineon divaricatum var. hookeri | Apiaceae
|
| MUVA | Musineon vaginatum Rydb. | sheathed wildparsley | Apiaceae
|
| MUSIN | Musineon Raf. | wildparsley | Apiaceae
|
| MUDIH2 | Musineum divaricatum (Pursh) Nutt. ex Torr. & Gray var. hookeri Torr. & Gray | Musineon divaricatum var. hookeri | Apiaceae
|
| MUDI2 | Musineum divaricatum (Pursh) Nutt. ex Torr. & Gray | Musineon divaricatum var. divaricatum | Apiaceae
|
| MUTE5 | Musineum tenuifolium Nutt. ex Torr. & Gray | Musineon tenuifolium | Apiaceae
|
| MUFO2 | Mussaenda formosa Jacq. | Randia formosa | Rubiaceae
|
| MYIR | Myagrum irregulare Asso | Calepina irregularis | Brassicaceae
|
| MYPA4 | Myagrum paniculatum L. | Neslia paniculata | Brassicaceae
|
| MYPE | Myagrum perfoliatum L. | bird's-eye cress | Brassicaceae
|
| MYPR | Myagrum prostratum Bergeret | Rorippa prostrata | Brassicaceae
|
| MYRU | Myagrum rugosum L. | Rapistrum rugosum ssp. rugosum | Brassicaceae
|
| MYSA3 | Myagrum sativum L. | Camelina sativa ssp. sativa | Brassicaceae
|
| MYAGR | Myagrum L. | myagrum | Brassicaceae
|
| MYMU | Mycelis muralis (L.) Dumort. | wall-lettuce | Asteraceae
|
| MYCEL | Mycelis Cass. | mycelis | Asteraceae
|
| MYBE3 | Mycobilimbia berengeriana (A. Massal.) Hafellner & V. Wirth | | Porpidiaceae
|
| MYCA14 | Mycobilimbia carneoalbida (Mull. Arg.) | | Porpidiaceae
|
| MYEP | Mycobilimbia epixanthoides (Nyl.) | | Porpidiaceae
|
| MYFI | Mycobilimbia fissuriseda (Poelt) Poelt & Hafellner | | Porpidiaceae
|
| MYFU | Mycobilimbia fusca (A. Massal.) Hafellner & V. Wirth | Mycobilimbia tetramera | Porpidiaceae
|
| MYHY | Mycobilimbia hypnorum (Lib.) Kalb. & Hafellner | | Porpidiaceae
|
| MYLO | Mycobilimbia lobulata (Sommerf.) Hafellner | | Porpidiaceae
|
| MYMI3 | Mycobilimbia microcarpa (Th. Fr.) W. Brunnbauer | Bacidia microcarpa | Bacidiaceae
|
| MYOB3 | Mycobilimbia obscurata (Sommerf.) Rehm | Mycobilimbia tetramera | Porpidiaceae
|
| MYSA4 | Mycobilimbia sabuletorum (Schreber) Hafellner | Bacidia sabuletorum | Bacidiaceae
|
| MYSP5 | Mycobilimbia sphaeroides (Dickson) | | Porpidiaceae
|
| MYTE4 | Mycobilimbia tetramera (De Not.) W. Brunnbauer | | Porpidiaceae
|
| MYCOB2 | Mycobilimbia Rehm | mycobilimbia | Porpidiaceae
|
| MYAF | Mycoblastus affinis (Schaerer) Schauer | blood lichen | Mycoblastaceae
|
| MYAL5 | Mycoblastus alpinus (Fr.) Kernst. | alpine blood lichen | Mycoblastaceae
|
| MYCA11 | Mycoblastus caesius (Coppins & P. James) Tonsberg | blood lichen | Mycoblastaceae
|
| MYFU3 | Mycoblastus fucatus (Stirton) Zahlbr. | blood lichen | Mycoblastaceae
|
| MYMA3 | Mycoblastus marginatus Degel. | blood lichen | Mycoblastaceae
|
| MYME5 | Mycoblastus melinus (Krempelh. ex Nyl.) Hellbom | Mycoblastus affinis | Mycoblastaceae
|
| MYSA5 | Mycoblastus sanguinarius (L.) Norman | blood lichen | Mycoblastaceae
|
| MYTO | Mycoblastus tornoensis (Nyl.) R. Anderson | Japewia tornoensis | Bacidiaceae
|
| MYCOB3 | Mycoblastus Norman | blood lichen | Mycoblastaceae
|
| MYAL7 | Mycocalicium albonigrum (Nyl.) Fink | | Mycocaliciaceae
|
| MYAM | Mycocalicium americanum (R. Sant.) Tibell | | Mycocaliciaceae
|