| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| NIQUQ | Nicotiana quadrivalvis Pursh var. quadrivalvis | Indian tobacco | Solanaceae
|
| NIQUW | Nicotiana quadrivalvis Pursh var. wallacei (Gray) Mansf. | Wallace's tobacco | Solanaceae
|
| NIQU | Nicotiana quadrivalvis Pursh | Indian tobacco | Solanaceae
|
| NIRE | Nicotiana repanda Willd. ex Lehm. | fiddleleaf tobacco | Solanaceae
|
| NIRU | Nicotiana rustica L. | Aztec tobacco | Solanaceae
|
| NISA | Nicotiana �sanderae hort. ex W. Wats. (pro sp.) | | Solanaceae
|
| NISU | Nicotiana suaveolens Lehm. | Australian tobacco | Solanaceae
|
| NISY | Nicotiana sylvestris Speg. & Comes | South American tobacco | Solanaceae
|
| NITA | Nicotiana tabacum L. | cultivated tobacco | Solanaceae
|
| NITO | Nicotiana tomentosa Ruiz & Pavon | tobacco | Solanaceae
|
| NITRP | Nicotiana trigonophylla Dunal var. palmeri (Gray) M.E. Jones | Nicotiana obtusifolia var. palmeri | Solanaceae
|
| NITR | Nicotiana trigonophylla Dunal | Nicotiana obtusifolia var. obtusifolia | Solanaceae
|
| NICOT | Nicotiana L. | tobacco | Solanaceae
|
| NIOT | Nidema ottonis (Reichenb. f.) Britt. & Millsp. | fairy orchid | Orchidaceae
|
| NIDEM | Nidema Britt. & Millsp. | nidema | Orchidaceae
|
| NICA | Niebla caespitosa Spjut | | Ramalinaceae
|
| NICE | Niebla cephalota (Tuck.) Rundel & Bowler | Vermilacinia cephalota | Ramalinaceae
|
| NICE3 | Niebla ceruchoides Rundel & Bowler | Vermilacinia ceruchoides | Ramalinaceae
|
| NICO2 | Niebla combeoides (Nyl.) Rundel & Bowler | Vermilacinia combeoides | Ramalinaceae
|
| NICO3 | Niebla cornea Spjut | | Ramalinaceae
|
| NIDA2 | Niebla dactylifera Spjut | | Ramalinaceae
|
| NIDI | Niebla disrupta (Nyl.) Spjut | | Ramalinaceae
|
| NIDI2 | Niebla dissecta Spjut | | Ramalinaceae
|
| NIEB | Niebla eburnea Spjut | | Ramalinaceae
|
| NIFI | Niebla fimbriata Spjut | | Ramalinaceae
|
| NIFL2 | Niebla flagelliforma Spjut | | Ramalinaceae
|
| NIHA | Niebla halei Spjut | | Ramalinaceae
|
| NIHO | Niebla homalea (Ach.) Rundel & Bowler | | Ramalinaceae
|
| NIIN | Niebla infundibula Spjut | | Ramalinaceae
|
| NIIS | Niebla isidiascens Bowler, Marsh, T. Nash & Riefner | | Ramalinaceae
|
| NILA2 | Niebla laevigata Bowler & Rundel | Vermilacinia laevigata | Ramalinaceae
|
| NILA3 | Niebla laminaria Spjut | | Ramalinaceae
|
| NIPA3 | Niebla palmeri Spjut | | Ramalinaceae
|
| NIPO | Niebla polymorpha Bowler, Marsh. T. Nash & Riefner | Vermilacinia polymorpha | Ramalinaceae
|
| NIPR | Niebla procera Rundel & Bowler | Vermilacinia procera | Ramalinaceae
|
| NIRA | Niebla ramosissima Spjut | | Ramalinaceae
|
| NIRO | Niebla robusta (R. H. Howe) Rundel & Bowler | Vermilacinia robusta | Ramalinaceae
|
| NISI | Niebla siphonoloba Spjut | | Ramalinaceae
|
| NISO | Niebla sorediata Spjut | | Ramalinaceae
|
| NISO2 | Niebla sorocarpia Spjut | | Ramalinaceae
|
| NITE | Niebla testudinaria (Nyl.) Spjut | | Ramalinaceae
|
| NITU | Niebla tuberculata Reifner, Bowler, Marsh & T. Nash | Vermilacinia tuberculata | Ramalinaceae
|
| NIUN | Niebla undulata Spjut | | Ramalinaceae
|
| NIEBL | Niebla Rundel & Bowler | niebla | Ramalinaceae
|
| NIFR | Nierembergia frutescens Durieu | tall cupflower | Solanaceae
|
| NIHIC | Nierembergia hippomanica Miers var. caerulea (Miers) Mill�n | dwarf cupflower | Solanaceae
|
| NIHI | Nierembergia hippomanica Miers | dwarf cupflower | Solanaceae
|
| NISC2 | Nierembergia scoparia Sendtner | broom cupflower | Solanaceae
|
| NIVI2 | Nierembergia viscosa Torr. | Hunzikeria texana | Solanaceae
|
| NIERE | Nierembergia Ruiz & Pav�n | cupflower | Solanaceae
|
| NIDA | Nigella damascena L. | devil in the bush | Ranunculaceae
|
| NIHI2 | Nigella hispanica L. | Spanish fennel | Ranunculaceae
|
| NISA2 | Nigella sativa L. | black cumin | Ranunculaceae
|
| NIGEL | Nigella L. | nigella | Ranunculaceae
|
| NIJA | Nintooa japonica (Thunb.) Sweet | Lonicera japonica | Caprifoliaceae
|
| NICA2 | Niobe caerulea (Andr.) Nash | Hosta ventricosa | Liliaceae
|
| NICO | Niobe coerulea (Andr.) Nash [orthographic variant] | Hosta ventricosa | Liliaceae
|
| NIJA2 | Niobe japonica (Thunb.) Nash | Hosta lancifolia | Liliaceae
|
| NIPE | Niopa peregrina (L.) Britt. & Rose | Anadenanthera peregrina | Fabaceae
|
| NICR | Niphidium crassifolium (L.) Lellinger | graceful fern | Polypodiaceae
|
| NIPHI | Niphidium J. Sm. | graceful fern | Polypodiaceae
|
| NIPL | Nissolia platycalyx S. Wats. | broadsepal yellowhood | Fabaceae
|
| NISC | Nissolia schottii (Torr.) Gray | Schott's yellowhood | Fabaceae
|
| NIWI | Nissolia wislizeni (Gray) Gray | Arizona yellowhood | Fabaceae
|
| NISSO | Nissolia Jacq. | yellowhood | Fabaceae
|
| NIMO | Nitrophila mohavensis Munz & Roos | Amargosa niterwort | Chenopodiaceae
|
| NIOC2 | Nitrophila occidentalis (Moq.) S. Wats. | boraxweed | Chenopodiaceae
|
| NITRO | Nitrophila S. Wats. | niterwort | Chenopodiaceae
|
| NOMO | Nocca mollis (Cav.) Jacq. | Lagascea mollis | Asteraceae
|
| NOCO3 | Noccaea cochleariformis (DC.) A.& D. L�ve | Thlaspi montanum var. montanum | Brassicaceae
|
| NOMOA | Noccaea montana (L.) F.K. Mey. ssp. arctica (Porsild) A.& D. L�ve | Thlaspi arcticum | Brassicaceae
|
| NOMO2 | Noccaea montana (L.) F.K. Mey. | Thlaspi montanum var. montanum | Brassicaceae
|
| NOAB | Nodobryoria abbreviata (Mull. Arg.) Common & Brodo | | Parmeliaceae
|
| NOOR3 | Nodobryoria oregana (Tuck.) Common & Brodo | | Parmeliaceae
|
| NOSU2 | Nodobryoria subdivergens (E. Dahl) Common & Brodo | | Parmeliaceae
|
| NODOB | Nodobryoria Common & Brodo | nodobryoria | Parmeliaceae
|
| NOAF2 | Nolina affinis Trel. | Nolina texana | Liliaceae
|
| NOAR | Nolina arenicola Correll | TransPecos beargrass | Liliaceae
|
| NOAT | Nolina atopocarpa Bartlett | Florida beargrass | Liliaceae
|
| NOBIP | Nolina bigelovii (Torr.) S. Wats. var. parryi (S. Wats.) L. Benson | Nolina parryi | Liliaceae
|
| NOBIW | Nolina bigelovii (Torr.) S. Wats. var. wolfii (Munz) L. Benson | Nolina parryi | Liliaceae
|
| NOBI | Nolina bigelovii (Torr.) S. Wats. | Bigelow's nolina | Liliaceae
|
| NOBR | Nolina brittoniana Nash | Britton's beargrass | Liliaceae
|
| NOCI | Nolina cismontana Dice | Peninsular beargrass | Liliaceae
|
| NOER | Nolina erumpens (Torr.) S. Wats. | foothill beargrass | Liliaceae
|
| NOGE | Nolina georgiana Michx. | Georgia beargrass | Liliaceae
|
| NOIN | Nolina interrata Gentry | Dehesa beargrass | Liliaceae
|
| NOLI | Nolina lindheimeriana (Scheele) S. Wats. | devil's shoestring | Liliaceae
|
| NOMI2 | Nolina micrantha I.M. Johnston | chaparral beargrass | Liliaceae
|
| NOMI | Nolina microcarpa S. Wats. | sacahuista | Liliaceae
|
| NOPAW2 | Nolina parryi S. Wats. ssp. wolfii Munz | Nolina parryi | Liliaceae
|
| NOPA | Nolina parryi S. Wats. | Parry's beargrass | Liliaceae
|
| NOTEC | Nolina texana S. Wats. var. compacta (Trel.) I.M. Johnston | Nolina texana | Liliaceae
|
| NOTE | Nolina texana S. Wats. | Texas sacahuista | Liliaceae
|
| NOWO | Nolina wolfii (Munz) Munz | Nolina parryi | Liliaceae
|
| NOLIN | Nolina Michx. | beargrass | Liliaceae
|
| NOST3 | Nomaphila stricta (Vahl) Nees | | Acanthaceae
|
| NOMAP | Nomaphila Blume | nomaphila | Acanthaceae
|
| NOLU | Nonea lutea (Desr.) Reichenb. ex DC. | yellow monkswort | Boraginaceae
|
| NORO | Nonea rosea (Bieb.) Link | rose monkswort | Boraginaceae
|
| NOVE | Nonea vesicaria (L.) Reichenb. | red monkswort | Boraginaceae
|