Ocimum americanum
American Basil
Ocinum americanum
American Basil
Odontites vernus
Red Bartsia
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
Opuntia cochenillifera
Cochineal Cactus
Opuntia ficus-indica
Prickly Pear
Opuntia microdasys
Angel's-wings
Origanum vulgare
Wild Marjoram
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
Orthilia secunda
Serrated Wintergreen
Osmoxylon lineare
Green Aralia
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
Papaver cambricum
Welsh Poppy
Papaver dubium
Long-headed Poppy
Papaver lecoqii
Yellow-juiced Poppy
Papaver rhoeas
Common Poppy
Papaver setiferum
Oriental Poppy
Parentucellia viscosa
Yellow Bartsia
Parietaria judaica
Pellitory-of-the-wall
Parnassia palustris
Grass-of-Parnassus
Passiflora caerulea
Blue Passionflower
Passiflora capsularis
Passion#Flower#(capsularis)
Passiflora foetida
Stinking Passionflower
Passiflora suberosa
Corkystem Passionflower
Pastinaca sativa
Wild Parsnip
Paulownia tomentosa
Foxglove-tree
Pedicularis foliosa
Leafy Lousewort
Pedicularis palustris
Marsh Lousewort
Pedicularis sylvatica
Lousewort
Pelargonium zonale
Zonal Geranium
Penstemon sp.
Penstemon
Pentaglottis sempervirens
Green Alkanet
Pentas lanceolata
Egyptian Starcluster
Peperomia pellucida
Pepper Elder
Peperomia polybotrya
Raindrop Peperomia
Pereskia aculeata
Barbados Gooseberry
Persicaria amphibia
Amphibious Bistort
Persicaria chinensis
Creeping Smartweed
Persicaria hydropiper
Water-pepper
Persicaria lapathifolia
Pale Persicaria
Persicaria maculosa
Redshank