Geum rivale
Water Avens
Geum urbanum
Wood Avens
Geum x intermedium
Hybrid Avens
Gladiolus illyricus
Wild Gladiolus
Glaucium flavum
Yellow Horned-poppy
Glechoma hederacea
Ground-ivy
Glyceria declinata
Small Sweet-grass
Glyceria fluitans
Floating Sweet-grass
Goodyera repens
Creeping Lady's-tresses
Gymnadenia borealis
Heath Fragrant-orchid
Gymnadenia conopsea
Fragrant Orchid
Gymnocarpium dryopteris
Oak Fern
Gymnocarpium robertianum
Limestone Fern
Hammarbya paludosa
Bog Orchid
Hedera helix sens lat
Ivy
Hedera hibernica
Atlantic Ivy
Helianthemum apenninum
White Rock-rose
Helianthemum nummularium
Common Rock-rose
Helianthemum oelandicum
Hoary Rock-rose
Helleborus foetidus
Stinking Hellebore
Helleborus viridis
Green Hellebore
Helosciadium inundatum
Lesser Marshwort
Helosciadium nodiflorum
Fool's-water-cress
Herminium monorchis
Musk Orchid
Hesperis matronalis
Dame's-violet
Himantoglossum hircinum
Lizard Orchid
Hippocrepis comosa
Horseshoe Vetch
Hippophae rhamnoides
Sea-buckthorn
Hippuris vulgaris
Mare's-tail
Holcus lanatus
Yorkshire-fog
Honckenya peploides
Sea Sandwort
Hordeum secalinum
Meadow Barley
Hottonia palustris
Water-violet
Humulus lupulus
Hop
Huperzia selago
Fir Clubmoss
Hyacinthoides hispanica
Spanish Bluebell
Hyacinthoides non-scripta
Bluebell
Hydrocharis morsus-ranae
Frogbit
Hydrocotyle vulgaris
Marsh Pennywort
Hylotelephium telephium
Orpine
Hymenophyllum tunbrigense
Tunbridge Filmy-fern
Hymenophyllum wilsonii
Wilson's Filmy-fern
Hypericum androsaemum
Tutsan
Hypericum calycinum
Rose-of-Sharon
Hypericum elodes
Marsh St John's-wort
Hypericum hirsutum
Hairy St John's-wort
Hypericum humifusum
Trailing St John's-wort
Hypericum maculatum
Imperforate 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
Hypochaeris maculata
Spotted Cat's-ear
Hypochaeris radicata
Cat's-ear
Hypopitys monotropa
Yellow Bird's-nest
Ilex aquifolium
Holly
Inula conyzae
Ploughman's-spikenard
Inula helenium
Elecampane
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isoetes echinospora
Spring Quillwort
Isoetes lacustris
Quillwort
Jacobaea vulgaris
Common Ragwort
Juglans regia
Walnut
Juncus acutiflorus
Sharp-flowered Rush
Juncus acutus
Sharp Rush
Juncus articulatus
Jointed Rush
Juncus bulbosus
Bulbous Rush
Juncus compressus
Round-fruited Rush
Juncus effusus
Soft-rush