Hypericum hirsutum
Hairy St John's-wort
Hypericum humifusum
Trailing St John's-wort
Hypericum perforatum
Perforate St John's-wort
Hypholoma fasciculare
Sulphur Tuft
Hypochaeris radicata
Cat's-ear
Hypopitys monotropa
Yellow Bird's-nest
Hyptis capitata
False Ironwort
Iberis amara
Wild Candytuft
Ilex aquifolium
Holly
Impatiens glandulifera
Indian Balsam
Impatiens noli-tangere
Touch-me-not Balsam
Inachis io
European Peacock Butterfly
Ipomoea carnea
Pink Morning Glory
Ipomoea hederacea
Ivy-leaved Morning Glory
Ipomoea obscura
Obscure Morning Glory
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isatis tinctoria
Woad
Isoetes lacustris
Quillwort
Jacobaea aquatica
Marsh Ragwort
Jasione montana
Sheep's-bit
Jatropha podagrica
Gout-plant
Juncus articulatus
Jointed Rush
Juncus compressus
Round-fruited Rush