Hornungia petraea
Hutchinsia
Houttuynia cordata
Fish-plant
Hoya imbricata
Wax Vine
Humulus lupulus
Hop
Huperzia selago
Fir Clubmoss
Hyacinthoides hispanica
Spanish Bluebell
Hyacinthoides italica
Italian Bluebell
Hyacinthoides non-scripta
Bluebell
Hydrangea petiolaris
Climbing Hydrangea
Hydrocharis morsus-ranae
Frogbit
Hydrocotyle hirta
Hydrocotyle vulgaris
Marsh Pennywort
Hylotelephium telephium
Orpine
Hymenocallis fragrans
Spider Lily
Hymenocallis littoralis
Beach Spider Lily
Hymenophyllum tunbrigense
Tunbridge Filmy-fern
Hymenophyllum wilsonii
Wilson's Filmy-fern
Hyophorbe lagenicaulis
Bottle Palm
Hypericum androsaemum
Tutsan
Hypericum elodes
Marsh St John's-wort
Hypericum hirsutum
Hairy St John's-wort
Hypericum humifusum
Trailing St John's-wort
Hypericum maculatum
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
Hypochaeris maculata
Spotted Cat's-ear
Hypochaeris radicata
Cat's-ear
Hypopitys monotropa
Yellow Bird's-nest
Iberis amara
Wild Candytuft
Ilex aquifolium
Holly
Illecebrum verticillatum
Coral-necklace
Impatiens glandulifera
Indian Balsam
Impatiens noli-tangere
Touch-me-not Balsam
Impatiens parviflora
Small Balsam
Imperata
Imperata cylindrica
Cogon Grass
Indigofera hirsuta
Hairy Indigo
Inula conyzae
Ploughman's-spikenard
Inula helenium
Elecampane
Ipomoea batatas
Sweet Potato
Ipomoea carnea
Bush Morning Glory
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isatis tinctoria
Woad
Isoetes echinospora
Spring Quillwort
Isoetes lacustris
Quillwort
Isolepis setacea
Bristle Club-rush
Ixora chinensis
Chinese Ixora
Jacobaea aquatica
Marsh Ragwort
Jacobaea vulgaris
Common Ragwort
Jasione montana
Sheep's-bit
Jatropha integerrima
Peregrina
Juglans regia
Walnut
Juncus acutus
Sharp Rush
Juncus articulatus
Jointed Rush
Juncus bufonius
Toad Rush
Juncus bulbosus
Bulbous Rush
Juncus compressus
Round-fruited Rush
Juncus inflexus
Hard Rush
Juncus squarrosus
Heath Rush
Juncus subnodulosus
Blunt-flowered Rush
Juncus tenuis
Slender Rush
Juniperus chinensis
Chinese Juniper
Juniperus communis
Juniper
Juniperus recurva
Himalayan Juniper
Justicia brandegeeana
Shrimp Plant