| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| RIRA3 | Ricinodendron rautanenii Schinz | manketti | Euphorbiaceae
|
| RICIN2 | Ricinodendron Muell. Arg. | ricinodendron | Euphorbiaceae
|
| RICO3 | Ricinus communis L. | castorbean | Euphorbiaceae
|
| RICIN | Ricinus L. | ricinus | Euphorbiaceae
|
| RIAL | Ridan alternifolia (L.) Britt. | Verbesina alternifolia | Asteraceae
|
| RIPA2 | Ridan paniculata (Walt.) Small | Verbesina walteri | Asteraceae
|
| RICO4 | Riddellia cooperi Gray | Psilostrophe cooperi | Asteraceae
|
| RITAS | Riddellia tagetina (Nutt.) Greene var. sparsiflora Gray | Psilostrophe sparsiflora | Asteraceae
|
| RITA | Riddellia tagetina (Nutt.) Greene | Psilostrophe tagetina var. tagetina | Asteraceae
|
| RIHI3 | Riedlea hirsuta (Cav.) A. DC. | Melochia spicata | Sterculiaceae
|
| RIAF | Riella affinis M. Howe & Underw. | | Riellaceae
|
| RIAM6 | Riella americana M. Howe & Underw. | | Riellaceae
|
| RIELL | Riella Mont. | | Riellaceae
|
| RILE2 | Rigiopappus leptocladus Gray | wireweed | Asteraceae
|
| RIGIO | Rigiopappus Gray | rigiopappus | Asteraceae
|
| RICE2 | Rimelia cetrata (Ach.) Hale & Fletcher | | Parmeliaceae
|
| RICO6 | Rimelia commensurata (Hale) Hale & Fletcher | | Parmeliaceae
|
| RIDI2 | Rimelia diffractaica (Essl.) Hale & Fletcher | | Parmeliaceae
|
| RIRE3 | Rimelia reticulata (Taylor) Hale & Fletcher | | Parmeliaceae
|
| RISI | Rimelia simulans (Hale) Hale & Fletcher | | Parmeliaceae
|
| RISU3 | Rimelia subisidiosa (Mull. Arg.) Hale & Fletcher | | Parmeliaceae
|
| RIMEL2 | Rimelia Hale & Fletcher | rimelia | Parmeliaceae
|
| RICO15 | Rimeliella conferenda (Hale) Kurok. | | Parmeliaceae
|
| RINE3 | Rimeliella neotropica (Kurok.) Kurok. | | Parmeliaceae
|
| RISU8 | Rimeliella subsumpta (Nyl.) Kurok. | | Parmeliaceae
|
| RISU9 | Rimeliella subtinctoria (Zahlbr.) Kurok. | | Parmeliaceae
|
| RIMEL3 | Rimeliella Kurok. | rimeliella | Parmeliaceae
|
| RIBA | Rimularia badioatra (Krempelh.) Hertel & Rambold | | Rimulariaceae
|
| RICA10 | Rimularia caeca (Lowe) Rambold & Printzen | | Rimulariaceae
|
| RIFU | Rimularia furvella (Nyl. ex Mudd) Hertel & Rambold | | Rimulariaceae
|
| RIGI | Rimularia gibbosa (Ach.) Coppins, Hertel & Rambold | | Rimulariaceae
|
| RIGY | Rimularia gyrizans (Nyl.) Hertel & Rambold | | Rimulariaceae
|
| RIIM | Rimularia impavida (Th. Fr.) Hertel & Rambold | | Rimulariaceae
|
| RIIN4 | Rimularia insularis (Nyl.) Rambold & Hertel | | Rimulariaceae
|
| RILI | Rimularia limborina Nyl. | | Rimulariaceae
|
| RISP2 | Rimularia sphacelata (Th. Fr.) Hertel & Rambold | | Rimulariaceae
|
| RIMUL | Rimularia Nyl. | rimularia | Rimulariaceae
|
| RIAD | Rinodina adirondackii H. Magn. | | Physciaceae
|
| RIAM5 | Rinodina americana de Lesd. | American rinodina lichen | Physciaceae
|
| RIAN | Rinodina angelica Stizenb. | Mobergia angelica | Physciaceae
|
| RIAN2 | Rinodina annulata H. Magn. | | Physciaceae
|
| RIAP | Rinodina applanata H. Magn. | | Physciaceae
|
| RIAR2 | Rinodina archaea (Ach.) Arnold | | Physciaceae
|
| RIAR4 | Rinodina archaeoides H. Magn. | Rinodina olivaceobrunnea | Physciaceae
|
| RIAR3 | Rinodina arctica H. Magn. | | Physciaceae
|
| RIAS2 | Rinodina ascociscana Tuck. | | Physciaceae
|
| RIAT3 | Rinodina aterrima Krempelh. ex Anzi | Lichenothelia scopularia | Lichenotheliaceae
|
| RIAT2 | Rinodina athallina H. Magn. | | Physciaceae
|
| RIBI3 | Rinodina biatorina Korber | Rinodina oxydata | Physciaceae
|
| RIBI2 | Rinodina bischoffii (Hepp) A. Massal. | | Physciaceae
|
| RIBO | Rinodina bolanderi H. Magn. | | Physciaceae
|
| RIBO2 | Rinodina bolodes Tuck. ex Fink | | Physciaceae
|
| RIBR3 | Rinodina brouardii de Lesd. | | Physciaceae
|
| RICA5 | Rinodina cacuminum (Th. Fr.) Malme | | Physciaceae
|
| RICA6 | Rinodina calcigena (Th. Fr.) Lynge | | Physciaceae
|
| RICA7 | Rinodina calculiformis W. A. Weber | Mobergia calculiformis | Physciaceae
|
| RICA9 | Rinodina californica H. Magn. | Dimelaena californica | Physciaceae
|
| RICA8 | Rinodina castaneomela (Nyl.) Arnold | | Physciaceae
|
| RICA11 | Rinodina castaneomelodes H. Mayrh. & Poelt | | Physciaceae
|
| RICH | Rinodina chrysomelaena Tuck. | | Physciaceae
|
| RICI | Rinodina cinereovirens (Vainio) Vainio | | Physciaceae
|
| RICO7 | Rinodina colobina (Ach.) Th. Fr. | | Physciaceae
|
| RICO8 | Rinodina colobinoides (Nyl.) Zahlbr. | | Physciaceae
|
| RICO9 | Rinodina coloradiana H. Magn. | | Physciaceae
|
| RICO10 | Rinodina confragosa (Ach.) Korber | | Physciaceae
|
| RICO11 | Rinodina conradii Korber | | Physciaceae
|
| RICO12 | Rinodina constrictula H. Magn. | | Physciaceae
|
| RICO13 | Rinodina corticola Arnold | | Physciaceae
|
| RIDA | Rinodina dakotensis H. Magn. | Amandinea dakotensis | Physciaceae
|
| RIDA2 | Rinodina darrowii E. D. Rudolph | | Physciaceae
|
| RIDE3 | Rinodina degeliana Coppins | | Physciaceae
|
| RIDE2 | Rinodina destituta (Nyl.) Zahlbr. | | Physciaceae
|
| RIDI3 | Rinodina dirinoides Zahlbr. | | Physciaceae
|
| RIDI5 | Rinodina disjuncta Sheard & Tonsberg | | Physciaceae
|
| RIEF | Rinodina efflorescens Malme | | Physciaceae
|
| RIEN | Rinodina endophragmia Lamb | | Physciaceae
|
| RIEU | Rinodina euryspora Zahlbr. in Hasse | Rinodina luridata | Physciaceae
|
| RIEX | Rinodina excrescens Vainio | | Physciaceae
|
| RIEX2 | Rinodina exigua (Ach.) Gray | | Physciaceae
|
| RIFI | Rinodina finkii H. Magn. | Amandinea dakotensis | Physciaceae
|
| RIGE | Rinodina gennarii Bagl. | | Physciaceae
|
| RIGL5 | Rinodina glauca Ropin | | Physciaceae
|
| RIGR7 | Rinodina granulans Vainio | | Physciaceae
|
| RIGR6 | Rinodina granuligera H. Magn. | | Physciaceae
|
| RIGR8 | Rinodina griseosoralifera Coppins | | Physciaceae
|
| RIHA | Rinodina halei H. Magn. | | Physciaceae
|
| RIHA2 | Rinodina hallii Tuck. | | Physciaceae
|
| RIHE3 | Rinodina herrei H. Magn. | | Physciaceae
|
| RIHU5 | Rinodina hueana Vainio | Dimelaena oreina | Physciaceae
|
| RIHY2 | Rinodina hyperborea H. Magn. | | Physciaceae
|
| RIIN5 | Rinodina inaequalis H. Magn. | Amandinea dakotensis | Physciaceae
|
| RIIN6 | Rinodina intermedia Bagl. | Rinodina conradii | Physciaceae
|
| RIIN7 | Rinodina interpolata (Stirton) Sheard | | Physciaceae
|
| RIIO | Rinodina iowensis Zahlbr. | | Physciaceae
|
| RIKE | Rinodina kentuckyensis Fink | | Physciaceae
|
| RILA4 | Rinodina laevigata (Ach.) Malme | | Physciaceae
|
| RILE5 | Rinodina lecanoides de Lesd. | | Physciaceae
|
| RILE6 | Rinodina lecanorina (A. Massal.) A. Massal. | | Physciaceae
|
| RILE7 | Rinodina lecideoides (Nyl.) Kernst. | | Physciaceae
|
| RILE8 | Rinodina lepida (Nyl.) Mull. Arg. | | Physciaceae
|
| RILI2 | Rinodina lignaria H. Magn. | Rinodina granulans | Physciaceae
|