| Vorschaubild | Art, Unterart oder Varietät | Familie |  | Fotos von | 
| Preview pict. | Species, Subspecies, or Variety | Family |  | Photos from | 
|  |  Obione \ Salzmelde / Sea Purslane (2 Syn.) |  | Chenopodiaceae \ Gänsefußgew. / Goosefoot Fam.
 |  |  | 
|  |  Ochlopoa \ Rispengras / Grass (2 Syn.) |  | Poaceae \ Süßgräser / Grass Fam. |  |  | 
|  | Ocimum basilicum \ Basilikum / Sweet Basil |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | D 
S | 
|  |  Odontarrhena \ Steinkraut / Alison, Madwort (2 Syn.) |  | Brassicaceae \ Kreuzblütler / Crucifers |  |  | 
|  |  Odontites \ Zahntrost / Bartsia (4 Taxa + 2 Syn.) |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  |  | 
|  |  Oenanthe \ Wasserfenchel, Rebendolde / Water Dropwort (9 Taxa + 1 Syn.) |  | Apiaceae \ Doldenblütler / Umbellifers |  |  | 
|  |  Oenothera \ Nachtkerze / Evening Primrose (42 Taxa + 7 Syn.) |  | Onagraceae \ Nachtkerzengew. / Willowherb Fam. |  |  | 
|  | Oeosporangium pteridioides subsp. acrosticum −−> Cheilanthes acrostica |  | Pteridopsida \ Echte Farne / True Ferns |  | Chi 
GR 
Kre 
Les 
Rho 
Sam 
Zyp | 
|  |  Olea \ Ölbaum, Olivenbaum / Olive (3 Taxa + 2 Syn.) |  | Oleaceae \ Ölbaumgewächse / Ash Fam. |  |  | 
|  | Oloptum miliaceum \ Gewöhnlicher Grannenreis / Rice Grass, Smilo Grass |  | Poaceae \ Süßgräser / Grass Fam. |  | Chi 
Kre 
Les 
Rho | 
|  |  Omalotheca \ Ruhrkraut / Cudweed (4 Syn.) |  | Asteraceae \ Korbblütler / Composite Fam. |  |  | 
|  | Omphalina ericetorum −−> Botrydina botrydioides
 ? |  | Lecanorales \ Flechten / Lichens |  | D | 
|  |  Omphalodes \ Nabelnüsschen / Navelwort (2 Taxa) |  | Boraginaceae \ Borretschgew. / Borrage Fam. |  |  | 
|  | Oncostema peruviana −−> Scilla peruviana |  | Liliaceae \ Liliengewächse / Lily Fam. |  | E 
P | 
|  |  Onobrychis \ Esparsette / Sainfoin (11 Taxa + 1 Syn.) |  | Fabaceae \ Schmetterlingsblütler / Legumes |  |  | 
|  | Onoclea sensibilis \ Perl-Farn / Sensible Fern |  | Pteridopsida \ Echte Farne / True Ferns |  | D | 
|  |  Ononis \ Hauhechel / Restharrow (16 Taxa) |  | Fabaceae \ Schmetterlingsblütler / Legumes |  |  | 
|  |  Onopordum \ Esels-Distel / Cotton Thistle (10 Taxa + 1 Syn.) |  | Asteraceae \ Korbblütler / Composite Fam. |  |  | 
|  |  Onosma \ Lotwurz / Goldendrop (15 Taxa) |  | Boraginaceae \ Borretschgew. / Borrage Fam. |  |  | 
|  | Ophioglossum vulgatum \ Gemeine Natternzunge / Adder's-Tongue |  | Ophioglossaceae \ Natternfarngew. / Adder's-Tongue Fern Fam.
 |  | D | 
|  |  Opopanax \ Heilwurz / Sweet Myrrh (2 Taxa) |  | Apiaceae \ Doldenblütler / Umbellifers |  |  | 
|  |  Opuntia \ Feigenkaktus / Prickly Pear (4 Taxa + 2 Syn.) |  | Cactaceae \ Kakteen / Cactus Fam. |  |  | 
|  | Oreochloa disticha \ Zweizeiliges Kopfgras / Oreochloa |  | Poaceae \ Süßgräser / Grass Fam. |  | A 
E 
I | 
|  |  Oreojuncus \ Binse / Rush (2 Syn.) |  | Juncaceae \ Binsengewächse / Rush Fam. |  |  | 
|  |  Oreomecon \ Mohn / Poppy (2 Syn.) |  | Papaveraceae \ Mohngewächse / Poppy Fam. |  |  | 
|  | Oreopteris limbosperma \ Berg-Farn, Berg-Lappen-Farn / Sweet Mountain Fern, Lemon-Scented Fern |  | Pteridopsida \ Echte Farne / True Ferns |  | D | 
|  | Oreoselinum majus −−> Peucedanum oreoselinum |  | Apiaceae \ Doldenblütler / Umbellifers |  | D 
F 
I | 
|  |  Origanum \ Majoran, Dost / Marjoram, Oregano (10 Taxa + 3 Syn.) |  | Lamiaceae \ Lippenblütler / Mint Fam. |  |  | 
|  |  Orlaya \ Breitsame / Orlaya (3 Taxa + 2 Syn.) |  | Apiaceae \ Doldenblütler / Umbellifers |  |  | 
|  | Ormenis nobilis −−> Chamaemelum nobile |  | Asteraceae \ Korbblütler / Composite Fam. |  | D 
F | 
|  |  Ornithogalum \ Milchstern / Star of Bethlehem (23 Taxa + 5 Syn.) |  | Liliaceae \ Liliengewächse / Lily Fam. |  |  | 
|  |  Ornithopus \ Vogelfuß / Bird's-Foot (3 Taxa) |  | Fabaceae \ Schmetterlingsblütler / Legumes |  |  | 
|  |  Orobanche \ Sommerwurz / Broomrape (31 Taxa + 16 Syn.) |  | Orobanchaceae \ Sommerwurzgew. / Broomrape Fam. |  |  | 
|  | Orthilia secunda \ Birngrün, Nickendes Wintergrün / Serrated Winter Green |  | Pyrolaceae \ Wintergrüngew. / Wintergreen Fam. |  | A 
D 
F 
HR | 
|  | Oryza sativa \ Reis / Rice |  | Poaceae \ Süßgräser / Grass Fam. |  | D 
F | 
|  | Osmunda regalis \ Königs-Farn / Royal Fern |  | Osmundaceae \ Königsfarngew. / Royal Fern Fam. |  | D 
E 
IRL | 
|  | Osteospermum ecklonis −−> Dimorphotheca ecklonis |  | Asteraceae \ Korbblütler / Composite Fam. |  | Kef | 
|  | Ostrya carpinifolia \ Hopfen-Buche / Hop Hornbeam |  | Betulaceae \ Birkengew. / Birch Fam. |  | D 
GR 
HR 
I | 
|  | Osyris alba \ Weißer Harnstrauch / Poet's Cassia |  | Santalaceae \ Sandelholzgew. / Sandalwood Fam. |  | F 
GR 
HR 
I | 
|  | Otanthus maritimus −−> Achillea maritima |  | Asteraceae \ Korbblütler / Composite Fam. |  | Cor 
GR 
Rho | 
|  |  Othocallis \ Blaustern / Squill (3 Syn.) |  | Liliaceae \ Liliengewächse / Lily Fam. |  |  | 
|  |  Oxalis \ Sauerklee / Sorrel (10 Taxa + 3 Syn.) |  | Oxalidaceae \ Sauerkleegew. / Wood-Sorrel Fam. |  |  | 
|  |  Oxybasis \ Gänsefuß / Goosefoot (5 Syn.) |  | Chenopodiaceae \ Gänsefußgew. / Goosefoot Fam.
 |  |  | 
|  | Oxycoccus palustris −−> Vaccinium oxycoccos |  | Ericaceae \ Heidekrautgew. / Heather Fam. |  | D 
S | 
|  | Oxyria digyna \ Alpen-Säuerling / Alpine Mountain Sorrel |  | Polygonaceae \ Knöterichgew. / Knotweed Fam. |  | A 
S | 
|  |  Oxytropis \ Spitzkiel / Milk-Vetch, Oxytropis (9 Taxa + 2 Syn.) |  | Fabaceae \ Schmetterlingsblütler / Legumes |  |  | 
|  |  oakesiana (2 Taxa) |  |  |  |  | 
|  |  obliqua (2 Taxa) |  |  |  |  | 
|  | oblonga, Cydonia \ Quitte / Quince |  | Rosaceae \ Rosengewächse / Rose Fam. |  | D 
Les | 
|  | oblongata, Euphorbia \ Eiblättrige Wolfsmilch / Eggleaf Spurge, Balkan Spurge |  | Euphorbiaceae \ Wolfsmilchgew. / Spurge Fam. |  | GR 
Les | 
|  | oblongatum, Taraxacum \ Rundlappiger Löwenzahn / Oblong-Leaved Dandelion ? |  | Asteraceae \ Korbblütler / Composite Fam. |  | D | 
|  | oblongifolia x patula, Atriplex −−> Atriplex x northusana |  | Chenopodiaceae \ Gänsefußgew. / Goosefoot Fam.
 |  | D | 
|  | oblongifolia, Atriplex \ Langblättrige Melde / Oblong Leaved Orache |  | Chenopodiaceae \ Gänsefußgew. / Goosefoot Fam.
 |  | D | 
|  | obovatum subsp. lanceolatum, Asplenium −−> Asplenium billotii |  | Pteridopsida \ Echte Farne / True Ferns |  | F | 
|  |  obscura (2 Taxa + 1 Syn.) |  |  |  |  | 
|  | obscurum, Epilobium \ Dunkelgrünes Weidenröschen / Dark-Green Willowherb, Short-Fruited Willowherb |  | Onagraceae \ Nachtkerzengew. / Willowherb Fam. |  | D | 
|  | obtusa, Eleocharis \ Eiförmige Sumpfbinse / Ovate Spike Rush |  | Cyperaceae \ Sauergräser / Sedge Fam. |  | D | 
|  | obtusangula, Callitriche \ Nussfrüchtiger Wasserstern / Blue-Fruited Water Starwort |  | Callitrichaceae \ Wassersterngew. / Water Starwort Fam.
 |  | D 
HR | 
|  | obtusangulus, Rubus \ Stumpfkantige Brombeere / Obtuse-Angle Bramble |  | Rosaceae \ Rosengewächse / Rose Fam. |  | D | 
|  |  obtusatum (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | obtusiflorus, Elymus \ Stumpfblütige Quecke / Obtuse Couch |  | Poaceae \ Süßgräser / Grass Fam. |  | D | 
|  | obtusifolia var. wildpretii, Euphorbia −−> Euphorbia broussonetii |  | Euphorbiaceae \ Wolfsmilchgew. / Spurge Fam. |  | Gom 
Ten | 
|  |  obtusifolia (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | obtusifolium, Acer \ Syrischer Ahorn / Syrian Maple |  | Aceraceae \ Ahorngewächse / Maple Fam. |  | Zyp | 
|  | obtusifolius s.l., Rumex \ Stumpfblättriger Ampfer / Broad-Leaved Dock |  | Polygonaceae \ Knöterichgew. / Knotweed Fam. |  | D | 
|  | obtusifolius subsp. obtusifolius, Rumex \ Stumpfblatt-Ampfer / Broad-Leaved Dock |  | Polygonaceae \ Knöterichgew. / Knotweed Fam. |  | D | 
|  |  obtusifolius subsp. sylvestris (2 Taxa) |  |  |  |  | 
|  | obtusifolius subsp. transiens, Rumex \ Mittlerer Stumpfblatt-Ampfer / Intermediate Broad-Leaved Dock |  | Polygonaceae \ Knöterichgew. / Knotweed Fam. |  | D | 
|  |  obtusifolius (2 Taxa) |  |  |  |  | 
|  | obtusiloba, Valerianella \ Stumpflappiger Feld-Salat / Obtuse-Lobed Corn Salad |  | Valerianaceae \ Baldriangew. / Valerian Fam. |  | Kre 
Mal | 
|  | obtusiusculum, Hypericum maculatum subsp. −−> Hypericum dubium |  | Hypericaceae \ Johanniskrautgew. / St.John's Wort Fam.
 |  | D | 
|  | occidentale, Phyteuma spicatum subsp. −−> Phyteuma spicatum subsp. coeruleum |  | Campanulaceae \ Glockenblumengew. / Bellflower Fam. |  | F | 
|  |  occidentalis (4 Taxa + 1 Syn.) |  |  |  |  | 
|  | occulta, Cardamine \ Japanisches Reisfeld-Schaumkraut / Japanese Rice-Field Bitter-Cress |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oceanica, Posidonia \ Neptun-Gras / Seagrass |  | Posidoniaceae \ Neptungrasgew. / Seagrass Fam. |  | Cor 
Kef 
Mal 
Zyp | 
|  | ochraceus subsp. ochraceus, Lathyrus \ Ockergelbe Platterbse / Yellow Pea |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | A 
S | 
|  | ochraceus, Lathyrus ochraceus subsp. \ Ockergelbe Platterbse / Yellow Pea |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | A 
S | 
|  | ochrocheila, Alyxoria \ Ockerfrüchtige Zeichen-Flechte / Scribble Lichen |  | Lecanorales \ Flechten / Lichens |  | D | 
|  | ochrochlora, Cladonia −−> Cladonia coniocraea |  | Lecanorales \ Flechten / Lichens |  | D | 
|  | ochroleuca subsp. stygia, Utricularia −−> Utricularia stygia |  | Lentibulariaceae \ Fettkrautgew. / Bladderwort Fam. |  | D | 
|  | ochroleuca, Scabiosa \ Gelbe Skabiose / Yellow Scabious |  | Dipsacaceae \ Kardengewächse / Teasel Fam. |  | A 
D | 
|  | ochroleucon, Trifolium \ Blaßgelber Klee / Sulphur Clover |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | A 
D 
F | 
|  |  ochroleucum (2 Taxa) |  |  |  |  | 
|  | ochrus, Lathyrus \ Flügel-Platterbse, Scheidige Platterbse / Winged Vetchling, Cyprus Vetch |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | Kre 
Mal | 
|  | octopetala, Dryas \ Silberwurz / Mountain Avens |  | Rosaceae \ Rosengewächse / Rose Fam. |  | A 
I 
IRL | 
|  |  oculus-christi (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | ocymastrum, Stachys \ Basilikum-Ziest / Hairy Woundwort |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | E 
Mal 
P | 
|  | ocymoides, Saponaria \ Rotes Seifenkraut / Rock Soapwort |  | Caryophyllaceae \ Nelkengew. / Campion Fam. |  | F 
I | 
|  | odora, Pulicaria \ Wohlriechendes Flohkraut / Mediterranean Fleabane |  | Asteraceae \ Korbblütler / Composite Fam. |  | Cor | 
|  | odorata var. sulphurea, Viola \ Wohlriechendes Veilchen, März-Veilchen / Sweet Violet |  | Violaceae \ Veilchengewächse / Violet Fam. |  | D | 
|  |  odorata (4 Taxa + 2 Syn.) |  |  |  |  | 
|  |  odoratum (4 Taxa) |  |  |  |  | 
|  |  odoratus (2 Taxa) |  |  |  |  | 
|  | oederi, Pedicularis \ Oeders Läusekraut, Buntes Läusekraut / Oeder's Lousewort |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  | A | 
|  | oehlkersii, Oenothera \ Oehlkers-Nachtkerze / Oehlkers' Evening Primrose |  | Onagraceae \ Nachtkerzengew. / Willowherb Fam. |  | D | 
|  | oelandicum subsp. alpestre, Helianthemum −−> Helianthemum alpestre |  | Cistaceae \ Zistrosengew. / Rockrose Fam. |  | A 
F 
I | 
|  | oelandicum subsp. italicum, Helianthemum −−> Helianthemum italicum |  | Cistaceae \ Zistrosengew. / Rockrose Fam. |  | F 
I | 
|  |  oelandicum (2 Taxa) |  |  |  |  | 
|  |  oellgaardii (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | oenipontana, Pulsatilla vulgaris var. \ Kuhschelle / Common Pasque-Flower |  | Ranunculaceae \ Hahnenfußgew. / Buttercup Fam. |  | D | 
|  | oenipontanus, Thymus \ Innsbrucker Thymian, Tiroler Quendel / Innsbruck Thyme |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | F 
I | 
|  | officinale subsp. bohemicum, Symphytum −−> Symphytum bohemicum |  | Boraginaceae \ Borretschgew. / Borrage Fam. |  | A 
D 
I | 
|  |  officinale (8 Taxa + 3 Syn.) |  |  |  |  | 
|  | officinalis agg., Valeriana \ Arznei-Baldrian / Common Valerian |  | Valerianaceae \ Baldriangew. / Valerian Fam. |  | CH 
D | 
|  | officinalis subsp. altissima, Melissa \ Kreta-Melisse / Balm |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | GR | 
|  | officinalis subsp. huthii, Paeonia \ Zottige Pfingstrose / Villous Peony |  | Paeoniaceae \ Pfingstrosengew. / Peony Fam. |  | F | 
|  | officinalis subsp. officinalis, Valeriana \ Echter Arznei-Baldrian / Common Valerian |  | Valerianaceae \ Baldriangew. / Valerian Fam. |  | F | 
|  | officinalis subsp. procera, Anchusa \ Große Ochsenzunge / Tall Bugloss |  | Boraginaceae \ Borretschgew. / Borrage Fam. |  | D | 
|  | officinalis subsp. tenuifolia, Valeriana −−> Valeriana pratensis subsp. angustifolia |  | Valerianaceae \ Baldriangew. / Valerian Fam. |  | A 
D 
F 
HR | 
|  | officinalis subsp. villosa, Paeonia −−> Paeonia officinalis subsp. huthii |  | Paeoniaceae \ Pfingstrosengew. / Peony Fam. |  | F | 
|  | officinalis subsp. wirtgenii, Fumaria −−> Fumaria wirtgenii |  | Fumariaceae \ Erdrauchgew. / Fumitory Fam. |  | D | 
|  |  officinalis (25 Taxa + 3 Syn.) |  |  |  |  | 
|  |  officinarum (1 Taxon + 4 Syn.) |  |  |  |  | 
|  |  olbia (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | oleander, Nerium \ Oleander / Oleander, Rose Bay |  | Apocynaceae \ Hundsgiftgew. / Periwinkle Fam. |  | D 
GR 
Kre 
Les 
Rho 
Zyp | 
|  | oleaster, Olea −−> Olea sylvestris |  | Oleaceae \ Ölbaumgewächse / Ash Fam. |  | F 
GR 
Rho 
Zyp | 
|  | oleiferus, Raphanus sativus subsp. −−> Raphanus sativus var. oleiformis |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oleifolius, Convolvulus \ Ölbaumblättrige Winde / Pink Bindweed |  | Convolvulaceae \ Windengew. / Bindweed Fam. |  | Rho 
Zyp | 
|  | oleiformis, Raphanus sativus var. \ Öl-Rettich / Oil Radish, Fodder Radish |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oleoides subsp. graeca, Rhamnus −−> Rhamnus lycioides subsp. graeca |  | Rhamnaceae \ Kreuzdorngew. / Buckthorn Fam. |  | GR 
Zyp | 
|  |  oleoides (2 Taxa + 1 Syn.) |  |  |  |  | 
|  | oleracea agg., Portulaca \ Wilder Portulak / Common Purslane |  | Portulacaceae \ Portulakgewächse / Purslane Fam.
 |  | A 
D 
F 
GR 
HR | 
|  | oleracea subsp. acephala, Brassica \ Gemüse-Kohl / Cale |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D 
F 
HR | 
|  | oleracea subsp. granulatostellulata, Portulaca −−> Portulaca granulatostellulata |  | Portulacaceae \ Portulakgewächse / Purslane Fam.
 |  | D | 
|  | oleracea subsp. nitida, Portulaca −−> Portulaca nitida |  | Portulacaceae \ Portulakgewächse / Purslane Fam.
 |  | D | 
|  | oleracea subsp. papillatostellulata, Portulaca −−> Portulaca papillatostellulata |  | Portulacaceae \ Portulakgewächse / Purslane Fam.
 |  | D | 
|  | oleracea var. botrydis, Brassica \ Blumenkohl, Karfiol / Cauliflower |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oleracea var. capitata, Brassica \ Kopfkohl, Kraut / Cabbage |  | Brassicaceae \ Kreuzblütler / Crucifers |  | Chi 
D | 
|  | oleracea var. italica, Brassica \ Brokkoli / Broccoli |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oleracea var. sabauda, Brassica \ Wirsing, Welsch-Kraut / Savoy Cabbage |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oleracea var. sabellica, Brassica \ Grünkohl, Krauskohl / Borecole, Curly Cole |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  | oleracea var. viridis, Brassica \ Blatt-Kohl / Collards, Cow Cabbage ? |  | Brassicaceae \ Kreuzblütler / Crucifers |  | D | 
|  |  oleracea (2 Taxa) |  |  |  |  | 
|  |  oleraceum (2 Taxa + 1 Syn.) |  |  |  |  | 
|  | oleraceus subsp. biflorus, Lathyrus \ Wilde Erbse, Feld-Erbse / Field Pea |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | Chi 
D 
GR 
HR 
I 
Les 
Rho | 
|  | oleraceus var. oleraceus, Lathyrus \ Garten-Erbse / Pea |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | D 
Zyp | 
|  |  oleraceus (2 Taxa) |  |  |  |  | 
|  | oligodon, Ranunculus \ Wenigzähniger Gold-Hahnenfuß / Few-Toothed Goldilocks |  | Ranunculaceae \ Hahnenfußgew. / Buttercup Fam. |  | F | 
|  | oligophyllum, Ornithogalum \ Wenigblättriger Milchstern / Star of Bethlehem |  | Liliaceae \ Liliengewächse / Lily Fam. |  | GR | 
|  | olivieri subsp. olivieri, Crocus \ Olivier-Krokus / Olivier's Crocus |  | Iridaceae \ Irisgewächse / Iris Fam. |  | Chi | 
|  | olivieri, Crocus olivieri subsp. \ Olivier-Krokus / Olivier's Crocus |  | Iridaceae \ Irisgewächse / Iris Fam. |  | Chi | 
|  | olusatrum, Smyrnium \ Gespenst-Gelbdolde, Pferde-Eppich / Alexanders |  | Apiaceae \ Doldenblütler / Umbellifers |  | I 
Kre 
Les 
Mal 
Rho 
Sam 
Zyp | 
|  | olympicum, Hypericum \ Zwerg-Johanniskraut / Mount Olymp St. John's-Wort |  | Hypericaceae \ Johanniskrautgew. / St.John's Wort Fam.
 |  | Cor 
D 
F | 
|  | olympicus, Rubus −−> Rubus austroslovacus |  | Rosaceae \ Rosengewächse / Rose Fam. |  | D | 
|  | omorika, Picea \ Serbische Fichte, Omorika-Fichte / Serbian Spruce |  | Pinaceae \ Kieferngewächse / Pine Fam. |  | D | 
|  | onites, Origanum \ Griechischer Majoran, Türkischer Oregano / Cretan Oregano, Turkish Oregano |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | Chi 
GR 
Rho | 
|  | onobrychioides, Vicia \ Esparsetten-Wicke / False Sainfoin |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | F 
I | 
|  | onobrychis, Astragalus \ Esparsetten-Tragant, Langfahnen-Tragant / Sainfoin Milk-Vetch |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | A 
I | 
|  | onopteris, Asplenium \ Spitzer Streifenfarn / Irish Spleenwort |  | Pteridopsida \ Echte Farne / True Ferns |  | E 
I 
Les | 
|  | onosmoides subsp. buglossoides, Hieracium \ Lotwurzblättriges Habichtskraut / Onosma-Leaved Hawkweed |  | Asteraceae \ Korbblütler / Composite Fam. |  | D | 
|  | onsdorfensis, Ranunculus \ Onsdorfer Gold-Hahnenfuß / Onsdorf Goldilocks |  | Ranunculaceae \ Hahnenfußgew. / Buttercup Fam. |  | D | 
|  | opaca, Veronica \ Glanzloser Ehrenpreis / Broadsepal Speedwell |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  | A | 
|  | opalus subsp. obtusatum, Acer −−> Acer obtusatum |  | Aceraceae \ Ahorngewächse / Maple Fam. |  | A 
D 
F 
HR | 
|  | opimus, Ranunculus \ Stattlicher Gold-Hahnenfuß, Feister Gold-Hahnenfuß / Portly Goldilocks |  | Ranunculaceae \ Hahnenfußgew. / Buttercup Fam. |  | D | 
|  | oppositifolia subsp. blepharophylla, Saxifraga \ Wimperblättriger Steinbrech / Ciliary-Leaved Saxifrage |  | Saxifragaceae \ Steinbrechgew. / Saxifrage Fam. |  | A | 
|  | oppositifolia subsp. oppositifolia, Saxifraga \ Gegenblättriger Steinbrech / Purple Saxifrage |  | Saxifragaceae \ Steinbrechgew. / Saxifrage Fam. |  | A 
E 
F | 
|  | oppositifolia, Saxifraga oppositifolia subsp. \ Gegenblättriger Steinbrech / Purple Saxifrage |  | Saxifragaceae \ Steinbrechgew. / Saxifrage Fam. |  | A 
E 
F | 
|  | oppositifolium, Chrysosplenium \ Gegenblättriges Milzkraut / Opposite-Leaved Golden-Saxifrage |  | Saxifragaceae \ Steinbrechgew. / Saxifrage Fam. |  | D 
F | 
|  | opulifolium, Chenopodium \ Schneeballblättriger Gänsefuß / Grey Goosefoot |  | Chenopodiaceae \ Gänsefußgew. / Goosefoot Fam.
 |  | D 
GR | 
|  | opulifolius, Physocarpus \ Schneeballblättrige Blasenspiere / Common Ninebark |  | Rosaceae \ Rosengewächse / Rose Fam. |  | D | 
|  | opulus, Viburnum \ Gewöhnlicher Schneeball, Wasser-Schneeball / Guelder Rose, Highbush Cranberry |  | Caprifoliaceae \ Geißblattgew. / Honeysuckle Fam.
 |  | D | 
|  | orbiculare, Phyteuma \ Kugel-Rapunzel / Round-Headed Rampion |  | Campanulaceae \ Glockenblumengew. / Bellflower Fam. |  | A 
D 
F 
HR 
I | 
|  |  orbicularis (3 Taxa) |  |  |  |  | 
|  |  orbiculatus (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | oreophilum, Aethionema saxatile subsp. −−> Aethionema saxatile subsp. graecum |  | Brassicaceae \ Kreuzblütler / Crucifers |  | GR | 
|  | oreophilus, Ranunculus −−> Ranunculus breyninus |  | Ranunculaceae \ Hahnenfußgew. / Buttercup Fam. |  | A 
D | 
|  | oreoselinum, Peucedanum \ Berg-Haarstrang / Mountain Parsley |  | Apiaceae \ Doldenblütler / Umbellifers |  | D 
F 
I | 
|  | orientale subsp. danicum, Arum −−> Arum cylindraceum |  | Araceae \ Aronstabgewächse / Arum Fam. |  | A 
GR | 
|  |  orientale (4 Taxa + 2 Syn.) |  |  |  |  | 
|  | orientalis subsp. aenesia, Ajuga \ Ainos-Günsel / Ainos Bugle |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | Kef | 
|  | orientalis x occidentalis, Platanus −−> Platanus x hispanica |  | Platanaceae \ Platanengew. / Plane Tree Fam. |  | D | 
|  |  orientalis (22 Taxa + 5 Syn.) |  |  |  |  | 
|  | origanifolia, Salpichroa \ Trompetenblume / Cock's Eggs |  | Solanaceae \ Nachtschattengew. / Nightshade Fam. |  | F | 
|  | origanifolium subsp. crassifolium, Chaenorhinum \ Dickblättriger Orant / Thick-Leaved Toadflax |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  | E 
F | 
|  | origanifolium subsp. origanifolium, Chaenorhinum \ Piemonteser Leinkraut / Dwarf Snapdragon, Malling Toadflax |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  | E 
F | 
|  | origanifolium subsp. serrae, Helianthemum \ Dostblättriges Sonnenröschen / Majoram-Leaved Rock-Rose |  | Cistaceae \ Zistrosengew. / Rockrose Fam. |  | Mal | 
|  |  origanifolium (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | ornata, Centaurea \ Zierliche Flockenblume / Decorated Knapweed |  | Asteraceae \ Korbblütler / Composite Fam. |  | E | 
|  | ornithopoda, Carex \ Vogelfuß-Segge / Bird's Foot Sedge |  | Cyperaceae \ Sauergräser / Sedge Fam. |  | D 
HR | 
|  |  ornithopodioides (3 Taxa) |  |  |  |  | 
|  | ornus, Fraxinus \ Blumen-Esche, Manna-Esche / Manna Ash |  | Oleaceae \ Ölbaumgewächse / Ash Fam. |  | A 
D 
GR 
HR 
I | 
|  | oroboides, Vicia \ Walderbsen-Wicke / Pale Vetch |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | HR | 
|  | orobus, Vicia \ Orber Wicke, Heide-Wicke / Wood Bitter-Vetch, Upright Vetch |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | D 
S | 
|  | oromediterraneus, Cytisus \ Abführender Geißklee / Andorra Broom |  | Fabaceae \ Schmetterlingsblütler / Legumes |  | F | 
|  | orontium, Misopates \ Acker-Löwenmaul, Großer Orant / Weasel's-Snout, Lesser Snapdragon |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  | Cor 
D 
F 
I 
Kre 
Mal 
Pal 
Rho 
Zyp | 
|  | orphanidea, Tulipa \ Orphanides-Tulpe / Orphanides Tulip |  | Liliaceae \ Liliengewächse / Lily Fam. |  | GR | 
|  | orphanidis, Biebersteinia \ Biebersteinia / Biebersteinia |  | Geraniaceae \ Storchschnabelgew. / Crane's-Bill Fam. |  | GR | 
|  | orsiniana, Veronica \ Orsinis Ehrenpreis / Orsini's Speedwell |  | Scrophulariaceae \ Braunwurzgew. / Figwort Fam. |  | D 
I | 
|  | orthoceras, Ceratocephala \ Geradfrüchtiges Hornköpfchen / Bur Buttercup |  | Ranunculaceae \ Hahnenfußgew. / Buttercup Fam. |  | D | 
|  | orthostachyoides, Rubus \ Geradachsenförmige Brombeere / Straight-Axis Bramble |  | Rosaceae \ Rosengewächse / Rose Fam. |  | D | 
|  | orthostachys, Rubus \ Geradachsige Haselblatt-Brombeere / Straight-Axis Bramble |  | Rosaceae \ Rosengewächse / Rose Fam. |  | D | 
|  | orvala, Lamium \ Große Taubnessel, Nesselkönig / Balm-Leaved Archangel |  | Lamiaceae \ Lippenblütler / Mint Fam. |  | A 
HR 
I 
SLO | 
|  | oryzoides, Leersia \ Wild-Reis / Rice Cutgrass |  | Poaceae \ Süßgräser / Grass Fam. |  | D 
S | 
|  |  osseum (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | ossifragum, Narthecium \ Beinbrech / Bog Asphodel |  | Liliaceae \ Liliengewächse / Lily Fam. |  | D 
F 
GB 
IRL | 
|  |  ostruthium (1 Taxon + 1 Syn.) |  |  |  |  | 
|  | otites, Silene \ Ohrlöffel-Leimkraut / Spanish Catchfly |  | Caryophyllaceae \ Nelkengew. / Campion Fam. |  | D | 
|  | otrubae, Carex \ Hain-Segge, Falsche Fuchs-Segge / False Fox Sedge |  | Cyperaceae \ Sauergräser / Sedge Fam. |  | A 
Cor 
D | 
|  | ottomanum, Symphytum \ Ottomanen-Beinwell / Ottoman Comfrey |  | Boraginaceae \ Borretschgew. / Borrage Fam. |  | GR | 
|  | ovalifolium, Ligustrum \ Ovalblättriger Liguster, Japanische Rainweide / California Privet, Oval-Leaved Privet |  | Oleaceae \ Ölbaumgewächse / Ash Fam. |  | IRL | 
|  |  ovalis (3 Taxa) |  |  |  |  | 
|  |  ovata (2 Taxa + 1 Syn.) |  |  |  |  | 
|  |  ovatum (2 Taxa + 1 Syn.) |  |  |  |  | 
|  |  ovatus (3 Taxa) |  |  |  |  | 
|  | ovina agg., Festuca \ Schaf-Schwingel / Sheep Fescue |  | Poaceae \ Süßgräser / Grass Fam. |  | A 
D | 
|  | ovina subsp. firmula, Festuca −−> Festuca medioeuropaea |  | Poaceae \ Süßgräser / Grass Fam. |  | A 
D | 
|  | ovina subsp. ovina, Festuca \ Schaf-Schwingel / Sheep Fescue |  | Poaceae \ Süßgräser / Grass Fam. |  | D | 
|  | ovina, Festuca ovina subsp. \ Schaf-Schwingel / Sheep Fescue |  | Poaceae \ Süßgräser / Grass Fam. |  | D | 
|  |  ovirensis (1 Taxon + 3 Syn.) |  |  |  |  | 
|  | oxelmannii, Corydalis blanda subsp. \ Oxelmanns Lerchensporn / Oxelmann's Corydalis |  | Fumariaceae \ Erdrauchgew. / Fumitory Fam. |  | GR | 
|  | oxonianum forma thurstonianum, Geranium x \ Thurstons Oxford-Storchschnabel / Thurston’s Oxford Crane's-Bill |  | Geraniaceae \ Storchschnabelgew. / Crane's-Bill Fam. |  | IRL | 
|  | oxonianum, Geranium x \ Oxford-Storchschnabel / Oxford Crane's-Bill |  | Geraniaceae \ Storchschnabelgew. / Crane's-Bill Fam. |  | D | 
|  | oxycedrus subsp. deltoides, Juniperus −−> Juniperus deltoides |  | Cupressaceae \ Zypressengew. / Cypresse Fam. |  | GR 
Rho | 
|  | oxycedrus, Juniperus \ Zedern-Wacholder / Prickly Juniper |  | Cupressaceae \ Zypressengew. / Cypresse Fam. |  | D 
F 
GR 
HR 
Rho | 
|  | oxycoccos, Vaccinium \ Gewöhnliche Moosbeere / Common Cranberry |  | Ericaceae \ Heidekrautgew. / Heather Fam. |  | D 
S | 
|  | oxyloba, Achillea \ Edle Schafgarbe, Dolomiten-Schafgarbe / Noble Yarrow, Alpine Sneezewort |  | Asteraceae \ Korbblütler / Composite Fam. |  | A 
I | 
|  | oxyodon, Hieracium \ Spitzzähniges Habichtskraut / Acute-Toothed Hawkweed |  | Asteraceae \ Korbblütler / Composite Fam. |  | D | 
|  | oxyptera, Polygala vulgaris var. \ Spitzflügelige Kreuzblume, Spitzflügeliges Kreuzblümchen / Sharp-Winged Milkwort |  | Polygalaceae \ Kreuzblumengew. / Milkwort Fam. |  | D | 
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