| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| ODIN | Odontonychia interior Small | Paronychia rugelii var. interior | Caryophyllaceae
|
| ODDED | Odontoschisma denudatum (Mart.) Dumort. var. denudatum | | Cephaloziaceae
|
| ODDEL | Odontoschisma denudatum (Mart.) Dumort. var. laevissima R. M. Schust. | | Cephaloziaceae
|
| ODDE3 | Odontoschisma denudatum (Mart.) Dumort. | | Cephaloziaceae
|
| ODEL | Odontoschisma elongatum (Lindb.) A. Evans | | Cephaloziaceae
|
| ODGI | Odontoschisma gibbsiae A. Evans | | Cephaloziaceae
|
| ODMA | Odontoschisma macounii (Austin) Underw. | | Cephaloziaceae
|
| ODPR | Odontoschisma prostratum (Sw.) Trevis. | | Cephaloziaceae
|
| ODSP | Odontoschisma sphagni (Dicks.) Dumort. | | Cephaloziaceae
|
| ODONT6 | Odontoschisma (Dumort.) Dumort. | | Cephaloziaceae
|
| ODAC | Odontosoria aculeata (L.) J. Sm. | thicket creepingfern | Dennstaedtiaceae
|
| ODCH | Odontosoria chinensis (L.) J. Sm. | Chinese creepingfern | Dennstaedtiaceae
|
| ODCL | Odontosoria clavata L. | clubbed creepingfern | Dennstaedtiaceae
|
| ODSC | Odontosoria scandens (Desv.) C. Christens. | border creepingfern | Dennstaedtiaceae
|
| ODUN | Odontosoria uncinella (Kunze) F�e | Odontosoria scandens | Dennstaedtiaceae
|
| ODONT | Odontosoria F�e | creepingfern | Dennstaedtiaceae
|
| ODBA | Odontostephana baldwyniana (Sweet) Alexander | Matelea baldwyniana | Asclepiadaceae
|
| ODCA | Odontostephana carolinensis (Jacq.) Alexander | Matelea carolinensis | Asclepiadaceae
|
| ODDE | Odontostephana decipiens Alexander | Matelea decipiens | Asclepiadaceae
|
| ODFL2 | Odontostephana flavidula (Chapman) Alexander | Matelea flavidula | Asclepiadaceae
|
| ODFL | Odontostephana floridana (Vail) Alexander | Matelea floridana | Asclepiadaceae
|
| ODOB | Odontostephana obliqua (Jacq.) Alexander | Matelea obliqua | Asclepiadaceae
|
| ODSH | Odontostephana shortii (Gray) Alexander | Matelea obliqua | Asclepiadaceae
|
| ODHA | Odontostomum hartwegii Torr. | Hartweg's doll's-lily | Liliaceae
|
| ODONT2 | Odontostomum Torr. | Hartweg's doll's-lily | Liliaceae
|
| ODDE2 | Odontotrichum decompositum (Gray) Rydb. | Psacalium decompositum | Asteraceae
|
| ODAQ | Odostemon aquifolium (Pursh) Rydb. | Mahonia aquifolium | Berberidaceae
|
| ODDI | Odostemon dictyota (Jepson) Cockerell | Mahonia dictyota | Berberidaceae
|
| ODFA | Odostemon fascicularis (DC.) Abrams | Mahonia pinnata ssp. pinnata | Berberidaceae
|
| ODFR | Odostemon fremontii (Torr.) Rydb. | Mahonia fremontii | Berberidaceae
|
| ODNE | Odostemon nervosus (Pursh) Rydb. | Mahonia nervosa | Berberidaceae
|
| ODNE2 | Odostemon nevinii (Gray) Abrams | Mahonia nevinii | Berberidaceae
|
| ODPU | Odostemon pumilus (Greene) Heller | Mahonia repens | Berberidaceae
|
| ODRE | Odostemon repens (Lindl.) Cockerell | Mahonia repens | Berberidaceae
|
| ODWI | Odostemon wilcoxii (Kearney) Heller | Berberis wilcoxii | Berberidaceae
|
| OEMA2 | Oeceoclades maculata (Lindl.) Lindl. | monk orchid | Orchidaceae
|
| OECEO | Oeceoclades Lindl. | monk orchid | Orchidaceae
|
| OETR3 | Oedera trinervia Spreng. | Flaveria trinervia | Asteraceae
|
| OEGR7 | Oedipodium griffithianum (Dicks.) Schwaegr. | Griffith's oedipodium moss | Oedipodiaceae
|
| OEDIP | Oedipodium Schwaegr. | oedipodium moss | Oedipodiaceae
|
| OECE | Oemleria cerasiformis (Torr. & Gray ex Hook. & Arn.) Landon | Indian plum | Rosaceae
|
| OEMLE | Oemleria Reichenb. | oemleria | Rosaceae
|
| OEAQ | Oenanthe aquatica (L.) Poir. | fineleaf waterdropwort | Apiaceae
|
| OEJAJ | Oenanthe javanica (Blume) DC. ssp. javanica | Java waterdropwort | Apiaceae
|
| OEJAS | Oenanthe javanica (Blume) DC. ssp. stolonifera (Wallich ex DC.) Murata | stolon waterdropwort | Apiaceae
|
| OEJA2 | Oenanthe javanica (Blume) DC. | Java waterdropwort | Apiaceae
|
| OEPI | Oenanthe pimpinelloides L. | corkyfruit waterdropwort | Apiaceae
|
| OESA | Oenanthe sarmentosa K. Presl ex DC. | water parsely | Apiaceae
|
| OEST5 | Oenanthe stolonifera Wallich ex DC. | Oenanthe javanica ssp. stolonifera | Apiaceae
|
| OENAN | Oenanthe L. | waterdropwort | Apiaceae
|
| OEAB | Oenothera abramsii J.F. Macbr. | Camissonia pallida ssp. pallida | Onagraceae
|
| OEAC | Oenothera acutissima W.L. Wagner | Flaming Gorge evening-primrose | Onagraceae
|
| OEAF | Oenothera affinis Camb. | longflower evening-primrose | Onagraceae
|
| OEAL | Oenothera albicaulis Pursh | whitest evening-primrose | Onagraceae
|
| OEAL3 | Oenothera albinervis R.R. Gates | Oenothera villosa ssp. villosa | Onagraceae
|
| OEALV2 | Oenothera alyssoides Hook. & Arn. var. villosa S. Wats. | Camissonia boothii ssp. alyssoides | Onagraceae
|
| OEAL4 | Oenothera alyssoides Hook. & Arn. | Camissonia boothii ssp. alyssoides | Onagraceae
|
| OEAM | Oenothera amplexicaulis (Woot. & Standl.) Tidestrom | Oenothera pubescens | Onagraceae
|
| OEANH | Oenothera andina Nutt. var. hilgardii (Greene) Munz | Camissonia hilgardii | Onagraceae
|
| OEAN3 | Oenothera andina Nutt. | Camissonia andina | Onagraceae
|
| OEAN2 | Oenothera angustissima R.R. Gates | Oenothera oakesiana | Onagraceae
|
| OEAR2 | Oenothera arenaria (A. Nels.) Raven | Camissonia arenaria | Onagraceae
|
| OEAR3 | Oenothera arenicola (Small) Coker | Oenothera fruticosa ssp. fruticosa | Onagraceae
|
| OEARP | Oenothera argillicola Mackenzie var. pubescens Core & Davis | Oenothera argillicola | Onagraceae
|
| OEAR | Oenothera argillicola Mackenzie | shalebarren evening-primrose | Onagraceae
|
| OEAR4 | Oenothera arizonica Munz | Oenothera californica ssp. arizonica | Onagraceae
|
| OEAU | Oenothera austromontana (Munz) Raven, W. Dietr. & Stubbe | Oenothera nutans | Onagraceae
|
| OEAVA | Oenothera avita (W. Klein) W. Klein ssp. arizonica (Munz) W. Klein | Oenothera californica ssp. arizonica | Onagraceae
|
| OEAVE | Oenothera avita (W. Klein) W. Klein ssp. eurekensis (Munz & Roos) W. Klein | Oenothera californica ssp. eurekensis | Onagraceae
|
| OEAV | Oenothera avita (W. Klein) W. Klein | Oenothera californica ssp. avita | Onagraceae
|
| OEBIA | Oenothera biennis L. ssp. austromontana Munz | Oenothera nutans | Onagraceae
|
| OEBIC | Oenothera biennis L. ssp. caeciarum Munz | Oenothera biennis | Onagraceae
|
| OEBIC3 | Oenothera biennis L. ssp. centralis Munz | Oenothera biennis | Onagraceae
|
| OEBIA2 | Oenothera biennis L. var. austromontana (Munz) Cronq. | Oenothera nutans | Onagraceae
|
| OEBIC2 | Oenothera biennis L. var. canescens Torr. & Gray | Oenothera villosa ssp. villosa | Onagraceae
|
| OEBIH3 | Oenothera biennis L. var. hirsutissima Gray ex S. Wats. | Oenothera elata ssp. hirsutissima | Onagraceae
|
| OEBIH2 | Oenothera biennis L. var. hookeri (Torr. & Gray) Boivin | Oenothera elata ssp. hookeri | Onagraceae
|
| OEBIN | Oenothera biennis L. var. nutans (Atkinson & Bartlett) Wieg. | Oenothera nutans | Onagraceae
|
| OEBIO | Oenothera biennis L. var. oakesiana Gray | Oenothera oakesiana | Onagraceae
|
| OEBIP | Oenothera biennis L. var. pycnocarpa (Atkinson & Bartlett) Wieg. | Oenothera biennis | Onagraceae
|
| OEBIS | Oenothera biennis L. var. strigosa (Rydb.) Piper | Oenothera villosa ssp. strigosa | Onagraceae
|
| OEBI | Oenothera biennis L. | common evening-primrose | Onagraceae
|
| OEBI3 | Oenothera bifrons D. Don, non Lindl. | Oenothera cordata | Onagraceae
|
| OEBIH | Oenothera bistorta Nutt. ex Torr. & Gray var. hallii (A. Davids.) Jepson | Camissonia pallida ssp. hallii | Onagraceae
|
| OEBIV | Oenothera bistorta Nutt. ex Torr. & Gray var. veitchiana Hook. | Camissonia bistorta | Onagraceae
|
| OEBI4 | Oenothera bistorta Nutt. ex Torr. & Gray | Camissonia bistorta | Onagraceae
|
| OEBOA | Oenothera boothii Dougl. ex Lehm. ssp. alyssoides (Hook. & Arn.) Munz | Camissonia boothii ssp. alyssoides | Onagraceae
|
| OEBOC | Oenothera boothii Dougl. ex Lehm. ssp. condensata (Munz) Munz | Camissonia boothii ssp. condensata | Onagraceae
|
| OEBOD | Oenothera boothii Dougl. ex Lehm. ssp. decorticans (Hook. & Arn.) Munz | Camissonia boothii ssp. decorticans | Onagraceae
|
| OEBOD2 | Oenothera boothii Dougl. ex Lehm. ssp. desertorum (Munz) Munz | Camissonia boothii ssp. desertorum | Onagraceae
|
| OEBOI2 | Oenothera boothii Dougl. ex Lehm. ssp. intermedia Munz | Camissonia boothii ssp. intermedia | Onagraceae
|
| OEBOI | Oenothera boothii Dougl. ex Lehm. ssp. inyoensis Munz | Camissonia boothii ssp. desertorum | Onagraceae
|
| OEBOR | Oenothera boothii Dougl. ex Lehm. ssp. rutila (A. Davids.) Munz | Camissonia boothii ssp. decorticans | Onagraceae
|
| OEBOP | Oenothera boothii Dougl. ex Lehm. var. pygmaea (Dougl. ex Lehm.) Torr. & Gray | Camissonia pygmaea | Onagraceae
|
| OEBO2 | Oenothera boothii Dougl. ex Lehm. | Camissonia boothii ssp. boothii | Onagraceae
|
| OEBRW | Oenothera brachycarpa Gray var. wrightii (Gray) Levl. | Oenothera brachycarpa | Onagraceae
|
| OEBR | Oenothera brachycarpa Gray | shortfruit evening-primrose | Onagraceae
|
| OEBR4 | Oenothera breviflora Torr. & Gray | Camissonia breviflora | Onagraceae
|
| OEBRA | Oenothera brevipes Gray ssp. arizonica Raven | Camissonia brevipes ssp. arizonica | Onagraceae
|
| OEBRP | Oenothera brevipes Gray ssp. pallidula (Munz) Raven | Camissonia brevipes ssp. pallidula | Onagraceae
|
| OEBRP2 | Oenothera brevipes Gray var. pallidula Munz | Camissonia brevipes ssp. pallidula | Onagraceae
|