Hieracium anglicum agg.
Hawkweed (anglicum agg.)
Hieracium cillense
Craig y Cilau Hawkweed
Hieracium lanatum
Hieracium maculatum
Spotted Hawkweed
Hieracium repandulare
Repand-leaved Hawkweed
Hieracium sect. Sabauda
Hieracium sect. Stelligera
Hawkweed (Stelligera)
Hieracium sect. Vulgata
Hieracium sp.
Hieracium subbritannicum
Hippobroma longiflora
Star of Bethlehem
Hippuris vulgaris
Mare's-tail
Hopea ferrea
Malut
Hornungia petraea
Hutchinsia
Hottonia palustris
Water-violet
Houttuynia cordata
Fish-plant
Humulus lupulus
Hop
Huperzia selago
Fir Clubmoss
Hyacinthoides italica
Italian Bluebell
Hyacinthoides non-scripta
Bluebell
Hydrangea macrophylla
Hydrangea
Hydrangea quercifolia
Oak-leaved Hydrangea
Hydrocotyle hirta
Hydrocotyle vulgaris
Marsh Pennywort
Hylotelephium telephium
Orpine
Hymenophyllum tunbrigense
Tunbridge Filmy-fern
Hymenophyllum wilsonii
Wilson's Filmy-fern
Hyophorbe lagenicaulis
Bottle Palm
Hyoscyamus niger
Henbane
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 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
Jatropha gossypiifolia
Bellyache Bush
Jatropha integerrima
Jatropha podagrica
Gout-plant
Juglans regia
Walnut
Juncus acutus
Sharp Rush
Juncus squarrosus
Heath Rush
Juniperus communis
Juniper
Juniperus recurva
Himalayan Juniper
Kickxia elatine
Sharp-leaved Fluellen
Knautia arvensis
Field Scabious
Laburnum anagyroides
Laburnum
Lactuca saligna
Least Lettuce
Lactuca serriola
Prickly Lettuce