Plant Database (by name)

Oklahoma evening-primrose - Oenothera macrocarpa Nutt. ssp. oklahomensis (J.B.S. Norton) Wagner

Oklahoma grasspink - Calopogon oklahomensis D.H. Goldman

Oklahoma plum - Prunus gracilis Engelm. & Gray

okra - Abelmoschus esculentus (L.) Moench

old man's whiskers - Geum triflorum Pursh

old man's whiskers - Geum triflorum Pursh var. ciliatum (Pursh) Fassett

old man's whiskers - Geum triflorum Pursh var. triflorum

old-man-in-the-Spring - Senecio vulgaris L.

oldenlandia - Oldenlandia L.

oldfield blackberry - Rubus alumnus Bailey

oldfield milkvine - Matelea decipiens (Alexander) Woods.

oldpasture bluegrass - Poa saltuensis Fern. & Wieg.

oldplainsman - Hymenopappus artemisiifolius DC. var. artemisiifolius

oldwoman - Artemisia stelleriana Bess.

oleander - Nerium oleander L.

oligotrichum moss - Oligotrichum hercynicum (Hedw.) Lam. & DC.

olive - Olea europaea L.

olivegreen calcareous moss - Mnium marginatum (With.) Brid. ex P. Beauv.

olneya - Olneya Gray

Olympic violet - Viola flettii Piper

oncophorus moss - Oncophorus virens (Hedw.) Brid.

onecolor dry rock moss - Grimmia unicolor Hook. in Grev.

oneflower false fiddleleaf - Hydrolea uniflora Raf.

oneflower fleabane - Erigeron uniflorus L.

oneflower fringed gentian - Gentianopsis simplex (Gray) Iltis

oneflower grama - Bouteloua uniflora Vasey

oneflower helianthella - Helianthella uniflora (Nutt.) Torr. & Gray

oneflower honeycombhead - Balduina uniflora Nutt.

oneflower stitchwort - Minuartia uniflora (Walt.) Mattf.

oneflowered broomrape - Orobanche uniflora L.

oneleaf onion - Allium unifolium Kellogg

oneseed burr cucumber - Sicyos angulatus L.

oneseed hawthorn - Crataegus monogyna Jacq.

oneseed juniper - Juniperus monosperma (Engelm.) Sarg.

oneseed pussypaws - Cistanthe monosperma (Greene) Hershkovitz

oneside penstemon - Penstemon unilateralis Rydb.

onespike danthonia - Danthonia unispicata (Thurb.) Munro ex Macoun

onespike paspalum - Paspalum unispicatum (Scribn. & Merr.) Nash

onion - Allium L.

oniongrass - Melica bulbosa Geyer ex Porter & Coult.

Ontario blazing star - Liatris cylindracea Michx.

Ontario dicranum moss - Dicranum ontariense Peters.

Ontario lobelia - Lobelia kalmii L.

Ontario rhodobryum moss - Rhodobryum ontariense (Kindb.) Par. in Kindb.

openfield sedge - Carex conoidea Schkuhr ex Willd.

openflower rosette grass - Dichanthelium laxiflorum (Lam.) Gould

opium poppy - Papaver somniferum L.

oppositeleaf bahia - Picradeniopsis oppositifolia (Nutt.) Rydb. ex Britt.

oppositeleaf lewisia - Lewisia oppositifolia (S. Wats.) B.L. Robins.

oppositeleaf spotflower - Acmella oppositifolia (Lam.) R.K. Jansen