Ophrys insectifera
Fly Orchid
Orchis mascula
Early-purple Orchid
Oreopteris limbosperma
Lemon-scented Fern
Ornithopus perpusillus
Bird's-foot
Orobanche hederae
Ivy Broomrape
Orobanche rapum-genistae
Greater Broomrape
Orontium aquaticum
Golden-club
Orthilia secunda
Serrated Wintergreen
Osmunda regalis
Royal Fern
Oxalis acetosella
Wood-sorrel
Oxybasis rubra
Red Goosefoot
Papaver cambricum
Welsh Poppy
Papaver rhoeas
Common Poppy
Parentucellia viscosa
Yellow Bartsia
Parietaria judaica
Pellitory-of-the-wall
Paris quadrifolia
Herb-paris
Pedicularis palustris
Marsh Lousewort
Pedicularis sylvatica
Lousewort
Pentaglottis sempervirens
Green Alkanet
Persicaria amphibia
Amphibious Bistort
Persicaria lapathifolia
Pale Persicaria
Persicaria maculosa
Redshank
Persicaria mitis
Tasteless Water-pepper
Petasites hybridus
Butterbur
Petasites japonicus
Giant Butterbur
Petasites pyrenaicus
Winter Heliotrope
Petrosedum forsterianum
Rock Stonecrop
Petrosedum rupestre
Reflexed Stonecrop
Peziza spp.
Phalaris arundinacea
Reed Canary-grass
Phegopteris connectilis
Beech Fern
Philodendron bipinnatifidum
Split-leaf Philodendron
Phleum arenarium
Sand Cat's-tail
Phleum bertolonii
Smaller Cat's-tail
Phragmites australis
Common Reed
Phymatosorus scolopendria
Monarch Fern
Picea sitchensis
Sitka Spruce
Picea smithiana
Morinda Spruce
Picris hieracioides
Hawkweed Oxtongue
Pilosella officinarum
Mouse-ear-hawkweed
Pilularia globulifera
Pillwort
Pimpinella saxifraga
Burnet-saxifrage
Pinguicula lusitanica
Pale Butterwort
Pinguicula vulgaris
Common Butterwort
Pinus sylvestris
Scots Pine
Pistia stratiotes
Water Cabbage
Plantago coronopus
Buck's-horn Plantain
Plantago lanceolata
Ribwort Plantain
Plantago major
Greater Plantain (subspecies intermedia)
Plantago maritima
Sea Plantain
Platanthera chlorantha
Greater Butterfly-orchid
Platanthera chlorantha and bifolia
Platanus orientalis
Oriental Plane
Platanus x hispanica
London Plane
Platycerium coronarium
Elkhorn fern
Platycerium grande
Giant Staghorn Fern
Polemonium pauciflorum
Polygala serpyllifolia
Heath Milkwort
Polygonatum odoratum
Angular Solomon's-seal
Polygonatum x hybridum
Garden Solomon's-seal
Polygonum arenastrum
Equal-leaved Knotgrass
Polygonum oxyspermum
Ray's Knotgrass
Polypodium cambricum
Southern Polypody
Polypodium interjectum
Intermediate Polypody
Polypodium vulgare
Polypody
Polypodium vulgare sens. lat.
Polypody
Polypogon viridis
Water Bent
Polystichum setiferum
Soft Shield-fern
Polytrichum commune
Common haircap
Polytrichum juniperinum
Juniper Haircap