Ocimum americanum
American Basil
Ocinum americanum
American Basil
Odontites vernus
Red Bartsia
Odontosoria chinensis
Lace Fern
Oenanthe aquatica
Fine-leaved Water-dropwort
Oenanthe crocata
Hemlock Water-dropwort
Oenanthe fistulosa
Tubular Water-dropwort
Oenanthe lachenalii
Parsley Water-dropwort
Oenanthe pimpinelloides
Corky-fruited Water-dropwort
Oenanthe silaifolia
Narrow-leaved Water-dropwort
Oenothera biennis
Small-flowered Evening-primrose
Oenothera glazioviana
Large-flowered Evening-primrose
Oenothera stricta
Fragrant Evening-primrose
Olearia macrodonta
New Zealand Holly
Onobrychis viciifolia
Sainfoin
Ononis arvensis
Ononis reclinata
Small Restharrow
Ononis repens
Common Restharrow
Ononis spinosa
Spiny Restharrow
Ophioglossum azoricum
Small Adder's-tongue
Ophioglossum vulgatum
Adder's-tongue
Ophiopogon jaburan
Giant Lilyturf
Ophrys apifera
Bee Orchid
Ophrys fuciflora
Late Spider-orchid
Ophrys insectifera
Fly Orchid
Ophrys insectifera x apifera
Ophrys sphegodes
Early Spider-orchid
Oplismenus compositus
Running Mountaingrass
Opuntia cochenillifera
Cochineal Cactus
Opuntia ficus-indica
Prickly Pear
Opuntia microdasys
Angel's-wings
Orchis mascula
Early-purple Orchid
Orchis militaris
Military Orchid
Orchis purpurea
Lady Orchid
Orchis simia
Monkey Orchid
Orchis x angusticruris
Lady#Orchid#/ Monkey#Orchid#hybrid
Oreopteris limbosperma
Lemon-scented Fern
Origanum vulgare
Wild Marjoram
Ornithogalum nutans
Drooping Star-of-Bethlehem
Ornithogalum pyrenaicum
Spiked Star-of-Bethlehem
Ornithogalum umbellatum
Star-of-Bethlehem
Ornithopus perpusillus
Bird's-foot
Orobanche caryophyllacea
Bedstraw Broomrape
Orobanche hederae
Ivy Broomrape
Orobanche minor
Common Broomrape
Orobanche picridis
Oxtongue Broomrape
Orobanche rapum-genistae
Greater Broomrape
Orontium aquaticum
Golden-club
Orthilia secunda
Serrated Wintergreen
Osmoxylon lineare
Green Aralia
Osmunda regalis
Royal Fern
Oxalis acetosella
Wood-sorrel
Oxalis articulata
Pink-sorrel
Oxalis corniculata
Creeping Woodsorrel
Oxalis incarnata
Pale Pink-sorrel
Oxalis triangularis
False Shamrock
Oxybasis glauca
Oak-leaved Goosefoot
Oxybasis rubra
Red Goosefoot
Pachira glabra
French Peanut
Pachystachus lutea
Golden Shrimp Plant
Pachystachys lutea
Golden Shrimp Plant
Paeonia peregrina
Peony
Palhinhaea cernua
Staghorn Clubmoss
Pancratium maritimum
Sea Daffodil
Pandanus tectorius
Thatch Screwpine
Panicum trichanthum
Thicket Panic Grass
Papaver cambricum
Welsh Poppy
Papaver dubium
Long-headed Poppy
Papaver lecoqii
Yellow-juiced Poppy
Papaver rhoeas
Common Poppy