Honckenya peploides
Sea Sandwort
Hordeum murinum
Wall Barley
Hordeum secalinum
Meadow Barley
Hordeum vulgare
Six-rowed Barley
Hornungia petraea
Hutchinsia
Hottonia palustris
Water-violet
Houttuynia cordata
Fish-plant
Humulus lupulus
Hop
Huperzia selago
Fir Clubmoss
Hyacinthoides hispanica
Spanish Bluebell
Hyacinthoides italica
Italian Bluebell
Hyacinthoides non-scripta
Bluebell
Hyacinthoides x massartiana
Garden Bluebell
Hydrocharis morsus-ranae
Frogbit
Hydrocotyle vulgaris
Marsh Pennywort
Hygrocybe calyptriformis
Pink Waxcap
Hygrocybe chlorophana
Hygrocybe coccinea
Scarlet waxcap
Hygrocybe conica
Blackening Wax Cap
Hygrocybe helobia
Hygrocybe miniata
Hygrocybe psittacina
Parrot Waxcap
Hygrocybe sp.
Hygrocybe virginea
Snowy Waxcap
Hygrophoropsis aurantiaca
False Chanterelle
Hylotelephium telephium
Orpine
Hymenophyllum spp.
Filmy-ferns
Hymenophyllum tunbrigense
Tunbridge Filmy-fern
Hymenophyllum wilsonii
Wilson's Filmy-fern
Hyoscyamus niger
Henbane
Hypericum
Hypericum androsaemum
Tutsan
Hypericum calycinum
Rose-of-Sharon
Hypericum elodes
Marsh St John's-wort
Hypericum hircinum
Stinking Tutsan
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
Hypericum x caesariense
Hypericum x desetangsii
Des Etangs' St John's-wort
Hypericum x inodorum
Tall Tutsan
Hypholoma fasciculare
Sulphur Tuft
Hypnum cupressiforme
Hypochaeris maculata
Spotted Cat's-ear
Hypochaeris radicata
Cat's-ear
Hypogymnia tubulosa
Hypopitys monotropa
Yellow Bird's-nest
Ilex aquifolium
Holly
Illecebrum verticillatum
Coral-necklace
Impatiens glandulifera
Indian Balsam
Impatiens noli-tangere
Touch-me-not Balsam
Impatiens parviflora
Small Balsam
Inonotus dryadeus
Oak Bracket
Inonotus hispidus
Shaggy Bracket
Inula conyzae
Ploughman's-spikenard
Inula helenium
Elecampane
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isoetes echinospora
Spring Quillwort
Isoetes lacustris
Quillwort
Isolepis setacea
Bristle Club-rush
Jacobaea aquatica
Marsh Ragwort
Jacobaea vulgaris
Common Ragwort
Jacobaea x ostenfeldii
Jasione montana
Sheep's-bit
Jasminum nudiflorum
Winter Jasmine