Hypericum humifusum
Trailing St John's-wort
Hypericum montanum
Pale St John's-wort
Hypericum perforatum
Perforate St John's-wort
Hypericum pulchrum
Slender St John's-wort
Hypericum tetrapterum
Square-stalked St John's-wort
Hypericum x caesariense
Hypericum x desetangsii
Des Etangs' St John's-wort
Hypericum x inodorum
Tall Tutsan
Hypochaeris maculata
Spotted Cat's-ear
Hypochaeris radicata
Cat's-ear
Iberis amara
Wild Candytuft
Ilex aquifolium
Holly
Impatiens noli-tangere
Touch-me-not Balsam
Impatiens parviflora
Small Balsam
Impatiens walleriana
Busy Lizzie
Indigofera suffruticosa
Guatemalan Indigo
Inula conyzae
Ploughman's-spikenard
Inula helenium
Elecampane
Ipomoea aquatica
Water Spinach
Ipomoea batatas
Sweet Potato
Ipomoea obscura
Obscure Morning Glory
Isatis tinctoria
Woad
Isoetes lacustris
Quillwort
Jacobaea aquatica
Marsh Ragwort