Hieracium sect. Oreadea
Hieracium sect. Sabauda
Hieracium sect. Stelligera
Hawkweed (Stelligera)
Hieracium sp.
Hieracium stenopholidium
Western Hawkweed
Hieracium subbritannicum
Hieracium tavense
Tawe Hawkweed
Hippeastrum puniceum
Amaryllis Lily
Hippophae rhamnoides
Sea-buckthorn
Hippuris vulgaris
Mare's-tail
Hirschfeldia incana
Hoary Mustard
Honckenya peploides
Sea Sandwort
Hordeum vulgare
Six-rowed Barley
Hornungia petraea
Hutchinsia
Hottonia palustris
Water-violet
Houttuynia cordata
Fish-plant
Humulus lupulus
Hop
Huperzia selago
Fir Clubmoss
Hyacinthoides non-scripta
Bluebell
Hydrocharis morsus-ranae
Frogbit
Hydrocotyle hirta
Hydrocotyle vulgaris
Marsh Pennywort
Hylotelephium telephium
Orpine
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 pulchrum
Slender St John's-wort
Hypericum x caesariense
Hypochaeris radicata
Cat's-ear
Hypopitys monotropa
Yellow Bird's-nest
Ilex aquifolium
Holly
Illecebrum verticillatum
Coral-necklace
Impatiens glandulifera
Indian Balsam
Impatiens noli-tangere
Touch-me-not Balsam
Imperata
Inula conyzae
Ploughman's-spikenard
Inula helenium
Elecampane
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isolepis setacea
Bristle Club-rush
Jacobaea aquatica
Marsh Ragwort
Jasione montana
Sheep's-bit
Juglans regia
Walnut
Juncus acutus
Sharp Rush
Juncus bulbosus
Bulbous Rush
Juncus compressus
Round-fruited Rush
Juncus inflexus
Hard Rush
Juncus squarrosus
Heath Rush
Juniperus communis
Juniper
Kickxia elatine
Sharp-leaved Fluellen
Koenigia polystachya
Himalayan Knotweed
Laburnum anagyroides
Laburnum
Lactuca serriola
Prickly Lettuce
Lamiastrum galeobdolon
Yellow Archangel
Lamium purpureum
Red Dead-nettle
Larix
Bonsai Larch
Larix decidua
European Larch
Lathraea clandestina
Purple Toothwort
Lathraea squamaria
Toothwort
Lathyrus japonicus
Sea Pea
Lathyrus latifolius
Broad-leaved Everlasting-pea
Lathyrus nissolia
Grass Vetchling
Lathyrus oleraceus
Garden Pea
Lemna
Lemna minor
Common Duckweed