| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| INDUS | Indusiella Broth. & C. Müll. in Broth. | indusiella moss | Grimmiaceae
|
| INED | Inga edulis C. Martius | icecreambean | Fabaceae
|
| INFA | Inga fagifolia (L.) Willd. ex Benth., non G. Don | Inga laurina | Fabaceae
|
| ININ2 | Inga inga (L.) Britt. | Inga vera | Fabaceae
|
| ININ | Inga ingoides (L.C. Rich.) Willd. | icecream bean | Fabaceae
|
| INLA | Inga laurina (Sw.) Willd. | sacky sac bean | Fabaceae
|
| INNOQ | Inga nobilis Willd. ssp. quaternata (Poepp. & Endl.) T.D. Pennington | guama venezolano | Fabaceae
|
| INNO | Inga nobilis Willd. | | Fabaceae
|
| INQU | Inga quaternata Poepp. & Endl. | Inga nobilis ssp. quaternata | Fabaceae
|
| INVE | Inga vera Willd. | river koko | Fabaceae
|
| INGA | Inga P. Mill. | inga | Fabaceae
|
| INFA3 | Inocarpus fagifer (Parkinson) F.R. Fosberg | | Fabaceae
|
| INOCA | Inocarpus J.R. & G. Forst. | | Fabaceae
|
| INEX | Inodes exul O.F. Cook | Sabal mexicana | Arecaceae
|
| INSC | Inodes schwarzii O.F. Cook | Sabal palmetto | Arecaceae
|
| INTE | Inodes texana O.F. Cook | Sabal mexicana | Arecaceae
|
| INAL | Inula alba Nutt. | Oligoneuron album | Asteraceae
|
| INBR | Inula britannica L. | British yellowhead | Asteraceae
|
| INDI | Inula divaricata Nutt. | Croptilon divaricatum | Asteraceae
|
| INDY | Inula dysenterica L. | Pulicaria dysenterica | Asteraceae
|
| INER | Inula ericoides Torr. | Chaetopappa ericoides | Asteraceae
|
| INGO | Inula gossypina Michx. | Chrysopsis gossypina ssp. gossypina | Asteraceae
|
| INGR | Inula graveolens (L.) Desf. | Dittrichia graveolens | Asteraceae
|
| INHE | Inula helenium L. | elecampane inula | Asteraceae
|
| INHO3 | Inula hookeri C.B. Clarke | Hooker inula | Asteraceae
|
| INMA | Inula mariana L. | Chrysopsis mariana | Asteraceae
|
| INSA | Inula salicina L. | willowleaf yellowhead | Asteraceae
|
| INVI | Inula viscosa (L.) Ait. | Dittrichia viscosa | Asteraceae
|
| INULA | Inula L. | yellowhead | Asteraceae
|
| IOCY | Iochroma cyaneum (Lindl.) M.L. Green | violet churur | Solanaceae
|
| IOFU | Iochroma fuchsioides (Bonpl.) Miers | | Solanaceae
|
| IOCHR | Iochroma Benth., nom. cons. | iochroma | Solanaceae
|
| IODE | Iodanthus dentatus (Torr.) Greene | Arabis shortii | Brassicaceae
|
| IOHE | Iodanthus hesperidioides (Torr. & Gray) Gray | Iodanthus pinnatifidus | Brassicaceae
|
| IOPI | Iodanthus pinnatifidus (Michx.) Steud. | purplerocket | Brassicaceae
|
| IODAN | Iodanthus Torr. & Gray | iodanthus | Brassicaceae
|
| IOAL | Ionactis alpina (Nutt.) Greene | Lava aster | Asteraceae
|
| IOCA2 | Ionactis caelestis Leary & Nesom | Spring Mountain aster | Asteraceae
|
| IOEL | Ionactis elegans (Soreng & Spellenberg) Nesom | Sierra Blanca least-daisy | Asteraceae
|
| IOLI2 | Ionactis linariifolius (L.) Greene | flaxleaf whitetop aster | Asteraceae
|
| IOST | Ionactis stenomeres (Gray) Greene | Rocky Mountain aster | Asteraceae
|
| IONAC | Ionactis Greene | aster | Asteraceae
|
| IOAL2 | Ionaspis alba Lutzoni | | Hymeneliaceae
|
| IOAN | Ionaspis annularis H. Magn. | | Hymeneliaceae
|
| IOAR | Ionaspis arctica Lynge | Hymenelia arctica | Hymeneliaceae
|
| IOCH | Ionaspis chrysophana (Korber) Stein | Ionaspis suaveolens | Hymeneliaceae
|
| IOEPA | Ionaspis epulotica (Ach.) Arnold var. arctica (Lynge) H. Magn. | Hymenelia arctica | Hymeneliaceae
|
| IOEP | Ionaspis epulotica (Ach.) Arnold | Hymenelia euplotica | Hymeneliaceae
|
| IOHE2 | Ionaspis heteromorpha (Krempelh.) Arnold | Hymenelia heteromorpha | Hymeneliaceae
|
| IOLA2 | Ionaspis lacustris (With.) Lutzoni | | Hymeneliaceae
|
| IOLA | Ionaspis lavata H. Magn. | | Hymeneliaceae
|
| IOME | Ionaspis melanocarpa (Krempelh.) Arnold | Hymenelia melanocarpa | Hymeneliaceae
|
| IOOC | Ionaspis ochracella (Nyl.) H. Magn. | Hymenelia melanocarpa | Hymeneliaceae
|
| IOOC2 | Ionaspis ochromicra (Nyl.) Hue | Hymenelia rhodopsis | Hymeneliaceae
|
| IOOD | Ionaspis odora (Ach.) Stein | | Hymeneliaceae
|
| IORE | Ionaspis reducta H. Magn. | Hymenelia melanocarpa | Hymeneliaceae
|
| IOSC | Ionaspis schismatopsis (Nyl.) Hue | Hymenelia heteromorpha | Hymeneliaceae
|
| IOSP | Ionaspis spitsbergensis H. Magn. | | Hymeneliaceae
|
| IOSU3 | Ionaspis suaveolens (Ach. ex Schaerer) Stein | Ionaspis suaveolens | Hymeneliaceae
|
| IOSU | Ionaspis suaveolens (Fr.) Th. Fr. | | Hymeneliaceae
|
| IONAS | Ionaspis Th. Fr. | ionaspis | Hymeneliaceae
|
| IOLI | Ionidium linearifolium (Vahl) Gingins | Hybanthus linearifolius | Violaceae
|
| IOPO2 | Ionidium portoricense (Urban) Krug & Urban ex Britt. & Wilson | Hybanthus linearifolius | Violaceae
|
| IOAC2 | Ionopsidium acaule (Desf.) Reichenb. | false diamondflower | Brassicaceae
|
| IONOP3 | Ionopsidium Reichenb. | ionopsidium | Brassicaceae
|
| IOSA | Ionopsis satyrioides (Sw.) Reichenb. f. | fleshyleaf violet orchid | Orchidaceae
|
| IOUT | Ionopsis utricularioides (Sw.) Lindl. | delicate violet orchid | Orchidaceae
|
| IONOP2 | Ionopsis Kunth | violet orchid | Orchidaceae
|
| IOCA | Ionoxalis caerulea Small | Oxalis caerulea | Oxalidaceae
|
| IOIN | Ionoxalis intermedia (A. Rich.) Small | Oxalis intermedia | Oxalidaceae
|
| IOMA | Ionoxalis martiana (Zucc.) Small | Oxalis latifolia | Oxalidaceae
|
| IOVI | Ionoxalis violacea (L.) Small | Oxalis violacea | Oxalidaceae
|
| IOPO | Ioxylon pomiferum Raf. | Maclura pomifera | Moraceae
|
| IPUN | Ipheion uniflorum (Graham) Raf. | Tristagma uniflorum | Liliaceae
|
| IPAC | Ipomoea acuminata (Vahl) Roemer & J.A. Schultes | Ipomoea indica | Convolvulaceae
|
| IPAE | Ipomoea aegyptia L. | Merremia aegyptia | Convolvulaceae
|
| IPAL | Ipomoea alba L. | tropical white morning-glory | Convolvulaceae
|
| IPAM | Ipomoea amnicola Morong | redcenter morning-glory | Convolvulaceae
|
| IPAN | Ipomoea angustifolia Jacq. | Xenostegia tridentata | Convolvulaceae
|
| IPAQ | Ipomoea aquatica Forsk. | swamp morning-glory | Convolvulaceae
|
| IPAR | Ipomoea aristolochiifolia auct. non (Kunth) G. Don | Ipomoea cardiophylla | Convolvulaceae
|
| IPAS | Ipomoea asarifolia (Desr.) Roemer & J.A. Schultes | | Convolvulaceae
|
| IPBA | Ipomoea barbatisepala Gray | canyon morning-glory | Convolvulaceae
|
| IPBA3 | Ipomoea barbigera Sweet | Ipomoea hederacea | Convolvulaceae
|
| IPBA2 | Ipomoea batatas (L.) Lam. | sweetpotato | Convolvulaceae
|
| IPBO | Ipomoea bona-nox L. | Ipomoea alba | Convolvulaceae
|
| IPBR | Ipomoea brasiliensis (L.) Sweet | Ipomoea pes-caprae ssp. brasiliensis | Convolvulaceae
|
| IPCAH | Ipomoea cairica (L.) Sweet var. hederacea Hallier f. | Ipomoea cairica | Convolvulaceae
|
| IPCAL | Ipomoea cairica (L.) Sweet var. lineariloba (Hbd.) O. Deg. & van Ooststr. | Ipomoea cairica | Convolvulaceae
|
| IPCA | Ipomoea cairica (L.) Sweet | mile a minute vine | Convolvulaceae
|
| IPCA4 | Ipomoea calantha Griseb. | moonvine | Convolvulaceae
|
| IPCA11 | Ipomoea campanulata auct. non L. | Stictocardia tiliifolia | Convolvulaceae
|
| IPCA2 | Ipomoea capillacea (Kunth) G. Don | purple morning-glory | Convolvulaceae
|
| IPCA3 | Ipomoea cardiophylla Gray | heartleaf morning-glory | Convolvulaceae
|
| IPCAF | Ipomoea carnea Jacq. ssp. fistulosa (Mart. ex Choisy) D. Austin | gloria de la manana | Convolvulaceae
|
| IPCA5 | Ipomoea carnea Jacq. | gloria de la manana | Convolvulaceae
|
| IPCA8 | Ipomoea carolina (L.) Pursh, non L. | Ipomoea cordatotriloba var. cordatotriloba | Convolvulaceae
|
| IPCA10 | Ipomoea caroliniana sensu Small, non Poir. | Ipomoea cordatotriloba var. cordatotriloba | Convolvulaceae
|
| IPCA9 | Ipomoea cathartica Poir. | Ipomoea indica | Convolvulaceae
|
| IPCOH | Ipomoea coccinea L. var. hederifolia (L.) Gray | Ipomoea hederifolia | Convolvulaceae
|
| IPCO3 | Ipomoea coccinea L. | redstar | Convolvulaceae
|