Inula conyzae
Ploughman's-spikenard
Inula helenium
Elecampane
Ipomoea aquatica
Water Spinach
Ipomoea batatas
Sweet Potato
Ipomoea carnea
Pink Morning Glory
Ipomoea hederacea
Ivy-leaved Morning Glory
Ipomoea obscura
Obscure Morning Glory
Ipomoea tricolor
Mexican Morning Glory
Ipomoea triloba
Aiea Morning Glory
Iris
Iris
Iris douglasiana
Iris (douglasiana)
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Iris sibirica
Siberian Iris
Iris unguicularis
Algerian 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
Jacobaea x ostenfeldii
Jasione montana
Sheep's-bit