Neottia nidus-avis
Bird's-nest Orchid
Neottia ovata
Common Twayblade
Nuphar lutea
Yellow Water-lily
Oenanthe fistulosa
Tubular Water-dropwort
Oenanthe silaifolia
Narrow-leaved Water-dropwort
Ononis arvensis
Ophioglossum vulgatum
Adder's-tongue
Ophrys apifera
Bee Orchid
Ophrys fuciflora
Late Spider-orchid
Ophrys insectifera x apifera
Ophrys sphegodes
Early Spider-orchid
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
Orobanche caryophyllacea
Bedstraw Broomrape
Orobanche picridis
Oxtongue Broomrape
Orobanche rapum-genistae
Greater Broomrape
Orthilia secunda
Serrated Wintergreen
Osmunda regalis
Royal Fern
Oxalis acetosella
Wood-sorrel
Oxalis incarnata
Pale Pink-sorrel