| Symbol | Scientific name | Common name/Accepted name (for synonyms) | Family |
| OCGR2 | Ochrolechia grimmiae Lynge | grimmia crabseye lichen | Pertusariaceae
|
| OCGR3 | Ochrolechia groenlandica Vers. | Greenland crabseye lichen | Pertusariaceae
|
| OCGY | Ochrolechia gyalectina (Nyl.) Zahlbr. | crabseye lichen | Pertusariaceae
|
| OCIN60 | Ochrolechia inaequatula (Nyl.) Zahlbr. | crabseye lichen | Pertusariaceae
|
| OCJU | Ochrolechia juvenalis Brodo | crabseye lichen | Pertusariaceae
|
| OCLA3 | Ochrolechia laevigata (Rasanen) Vers. ex Brodo | crabseye lichen | Pertusariaceae
|
| OCME3 | Ochrolechia mexicana Vainio | crabseye lichen | Pertusariaceae
|
| OCMO3 | Ochrolechia montana Brodo | crabseye lichen | Pertusariaceae
|
| OCOR60 | Ochrolechia oregonensis H. Magn. | Oregon crabseye lichen | Pertusariaceae
|
| OCPA4 | Ochrolechia pacifica H. Magn. | Coccotrema pocillarium | Coccotremataceae
|
| OCPE | Ochrolechia pennsylvanica Vers. | Ochrolechia yasudae | Pertusariaceae
|
| OCPS2 | Ochrolechia pseudopallescens Brodo | crabseye lichen | Pertusariaceae
|
| OCPT | Ochrolechia pterulina (Nyl.) Howard | Ochrolechia frigida | Pertusariaceae
|
| OCRH2 | Ochrolechia rhodoleuca (Th. Fr.) Brodo | crabseye lichen | Pertusariaceae
|
| OCRO | Ochrolechia rosella (Mull. Arg.) Vers. | Ochrolechia trochophora | Pertusariaceae
|
| OCSO | Ochrolechia sorediosa Howard | Ochrolechia szatalaensis | Pertusariaceae
|
| OCSU | Ochrolechia subathallina H. Magn. | crabseye lichen | Pertusariaceae
|
| OCSU6 | Ochrolechia subisidiata Brodo | crabseye lichen | Pertusariaceae
|
| OCSU2 | Ochrolechia subpallescens Vers. | crabseye lichen | Pertusariaceae
|
| OCSUH | Ochrolechia subplicans (Nyl.) Brodo ssp. hultenii (Erichsen) Brodo | Hulten's crabseye lichen | Pertusariaceae
|
| OCSUS | Ochrolechia subplicans (Nyl.) Brodo ssp. subplicans | crabseye lichen | Pertusariaceae
|
| OCSU5 | Ochrolechia subplicans (Nyl.) Brodo | crabseye lichen | Pertusariaceae
|
| OCSZ | Ochrolechia szatalaensis Vers. | Szatala's crabseye lichen | Pertusariaceae
|
| OCTA | Ochrolechia tartarea (L.) A. Massal. | crabseye lichen | Pertusariaceae
|
| OCTR | Ochrolechia trachydactyla (Vainio) | crabseye lichen | Pertusariaceae
|
| OCTRP | Ochrolechia trochophora (Vainio) Oshio var. pruinirosella Brodo | crabseye lichen | Pertusariaceae
|
| OCTRT | Ochrolechia trochophora (Vainio) Oshio var. trochophora | crabseye lichen | Pertusariaceae
|
| OCTR2 | Ochrolechia trochophora (Vainio) Oshio | crabseye lichen | Pertusariaceae
|
| OCTU | Ochrolechia tuckermanii Vers. | Ochrolechia yasudae | Pertusariaceae
|
| OCTU2 | Ochrolechia turneri (Sm.) Hasselrot | Turner's crabseye lichen | Pertusariaceae
|
| OCUP60 | Ochrolechia upsaliensis (L.) A. Massal. | Upsala crabseye lichen | Pertusariaceae
|
| OCXA | Ochrolechia xanthostoma (Sommerf.) K. Schmitz & Lumbsch | crabseye lichen | Pertusariaceae
|
| OCYA | Ochrolechia yasudae Vainio | Yasuda's crabseye lichen | Pertusariaceae
|
| OCHRO3 | Ochrolechia A. Massal. | crabseye lichen | Pertusariaceae
|
| OCLA2 | Ochroma lagopus Sw. | Ochroma pyramidale | Bombacaceae
|
| OCPY | Ochroma pyramidale (Cav. ex Lam.) Urban | West Indian balsa | Bombacaceae
|
| OCHRO | Ochroma Sw. | ochroma | Bombacaceae
|
| OCCO | Ochrosia compta K. Schum. | holei | Apocynaceae
|
| OCEL | Ochrosia elliptica Labill. | elliptic yellowwood | Apocynaceae
|
| OCFO2 | Ochrosia forbesii St. John | Ochrosia compta | Apocynaceae
|
| OCHA | Ochrosia haleakalae St. John | island yellowwood | Apocynaceae
|
| OCHA2 | Ochrosia hamakuaensis St. John | Ochrosia haleakalae | Apocynaceae
|
| OCHO | Ochrosia holei St. John | Ochrosia compta | Apocynaceae
|
| OCKA | Ochrosia kauaiensis St. John | Kauai yellowwood | Apocynaceae
|
| OCKI | Ochrosia kilaueaensis St. John | Hawai'i yellowwood | Apocynaceae
|
| OCKO | Ochrosia konaensis St. John | Ochrosia kilaueaensis | Apocynaceae
|
| OCKO2 | Ochrosia kondoi St. John | Ochrosia compta | Apocynaceae
|
| OCLA | Ochrosia lamoureuxii St. John | Ochrosia compta | Apocynaceae
|
| OCMI | Ochrosia microcalyx St. John | Ochrosia compta | Apocynaceae
|
| OCSA2 | Ochrosia sandwicensis auct. non A. DC. | Ochrosia compta | Apocynaceae
|
| OCHRO2 | Ochrosia Juss. | yellowwood | Apocynaceae
|
| OCAM2 | Ocimum americanum L. | Ocimum basilicum | Lamiaceae
|
| OCAM3 | Ocimum americanum of authors | Ocimum canum | Lamiaceae
|
| OCBA | Ocimum basilicum L. | sweet basil | Lamiaceae
|
| OCCA5 | Ocimum campechianum P. Mill. | least basil | Lamiaceae
|
| OCCA4 | Ocimum canum Sims | hoary basil | Lamiaceae
|
| OCGR | Ocimum gratissimum L. | African basil | Lamiaceae
|
| OCKI2 | Ocimum kilimandscharicum Guerke | hoary basil | Lamiaceae
|
| OCMI2 | Ocimum micranthum Willd. | Ocimum campechianum | Lamiaceae
|
| OCSA3 | Ocimum salinum Molina | Frankenia salina | Frankeniaceae
|
| OCSA | Ocimum sanctum L. | Ocimum tenuiflorum | Lamiaceae
|
| OCTE2 | Ocimum tenuiflorum L. | holy basil | Lamiaceae
|
| OCVI | Ocimum viride Willd. | Ocimum gratissimum | Lamiaceae
|
| OCIMU | Ocimum L. | basil | Lamiaceae
|
| OCAC | Oclemena acuminata (Michx.) Greene | whorled wood aster | Asteraceae
|
| OCBL | Oclemena �blakei (Porter) Nesom | | Asteraceae
|
| OCNE2 | Oclemena nemoralis (Ait.) Greene | bog aster | Asteraceae
|
| OCRE2 | Oclemena reticulata (Pursh) Nesom | pinebarren whitetop aster | Asteraceae
|
| OCLEM | Oclemena Greene | aster | Asteraceae
|
| OCCO2 | Ocotea coriacea (Sw.) Britt. | Nectandra coriacea | Lauraceae
|
| OCCU | Ocotea cuneata (Griseb.) Urban | Ocotea nemodaphne | Lauraceae
|
| OCFL | Ocotea floribunda (Sw.) Mez | laurel espada | Lauraceae
|
| OCFO | Ocotea foeniculacea Mez | black sweetwood | Lauraceae
|
| OCGL | Ocotea globosa (Aubl.) Schlecht. & Cham. | Nectandra hihua | Lauraceae
|
| OCKR | Ocotea krugii (Mez) Howard | Nectandra krugii | Lauraceae
|
| OCLE | Ocotea leucoxylon (Sw.) De Laness. | loblolly sweetwood | Lauraceae
|
| OCME | Ocotea membranacea (Sw.) Howard | Nectandra membranacea | Lauraceae
|
| OCMO | Ocotea moschata (Pav�n ex Meisn.) Mez | nemoca | Lauraceae
|
| OCNE | Ocotea nemodaphne Mez | laurel sassafras | Lauraceae
|
| OCPA | Ocotea patens (Sw.) Nees | Nectandra patens | Lauraceae
|
| OCPO | Ocotea portoricensis Mez | laurel de paloma | Lauraceae
|
| OCSI | Ocotea sintenisii (Mez) Alain | Nectandra turbacensis | Lauraceae
|
| OCSP | Ocotea spathulata Mez | nemoca cimarrona | Lauraceae
|
| OCWR | Ocotea wrightii (Meisn.) Mez | Wright's laurel canelon | Lauraceae
|
| OCOTE | Ocotea Aubl. | sweetwood | Lauraceae
|
| OCMO2 | Octadesmia montana (Sw.) Benth. | Dilomilis montana | Orchidaceae
|
| OCAL2 | Octoblepharum albidum Hedw. | octoblepharum moss | Leucobryaceae
|
| OCTOB | Octoblepharum Hedw. | octoblepharum moss | Leucobryaceae
|
| ODSE | Odontites serotinus Dumort. | Odontites vernus ssp. serotinus | Scrophulariaceae
|
| ODVES | Odontites vernus (Bellardi) Dumort. ssp. serotinus (Dumort.) Corb. | red bartsia | Scrophulariaceae
|
| ODVE | Odontites vernus (Bellardi) Dumort. | red bartsia | Scrophulariaceae
|
| ODVU | Odontites vulgaris Moench | | Scrophulariaceae
|
| ODONT4 | Odontites Ludwig | odontites | Scrophulariaceae
|
| ODTR | Odontoglossum triumphans Rchb. F. & Warsz. | | Orchidaceae
|
| ODONT7 | Odontoglossum H.B. | odontoglossum | Orchidaceae
|
| ODCU | Odontonema cuspidatum (Nees) Kuntze | mottled toothedthread | Acanthaceae
|
| ODNI | Odontonema nitidum (Jacq.) Kuntze | shrubby toothedthread | Acanthaceae
|
| ODST | Odontonema strictum (Nees) Kuntze | Odontonema tubiforme | Acanthaceae
|
| ODTU | Odontonema tubiforme (Bertol.) Kuntze | firespike | Acanthaceae
|
| ODONT5 | Odontonema Nees | toothedthread | Acanthaceae
|
| ODCO | Odontonychia corymbosa Small | Paronychia erecta var. corymbosa | Caryophyllaceae
|