Orobanche rapum-genistae
Greater Broomrape
Orthilia secunda
Serrated Wintergreen
Osmoxylon lineare
Green Aralia
Osmunda regalis
Royal Fern
Oxalis acetosella
Wood-sorrel
Oxalis incarnata
Pale Pink-sorrel
Oxybasis glauca
Oak-leaved Goosefoot
Papaver cambricum
Welsh Poppy
Paris quadrifolia
Herb-paris
Passiflora foetida
Stinking Passionflower
Pedicularis palustris
Marsh Lousewort
Pedicularis sylvatica
Lousewort
Pentas lanceolata
Egyptian Starcluster
Peperomia pellucida
Pepper Elder
Peperomia polybotrya
Raindrop Peperomia
Persicaria amphibia
Amphibious Bistort
Persicaria lapathifolia
Pale Persicaria
Petasites hybridus
Butterbur
Petasites pyrenaicus
Winter Heliotrope
Petasites spurius
Petrorhagia prolifera
Proliferous Pink
Petrosedum forsterianum
Rock Stonecrop
Petrosedum rupestre
Reflexed Stonecrop
Phacelia tanacetifolia
Phacelia