Index
- Ilex ambigua, Carolina holly, sand holly
- Ilex amelanchier, serviceberry holly
- Ilex cassine, dahoon holly
- Ilex cassine var. myrtifolia, myrtle-leaf holly
- Ilex coriacea, large gallberry
- Ilex decidua, possum haw
- Ilex glabra, inkberry, gallberry
- Ilex krugiana, Krug's holly
- Ilex opaca var. arenicola, scrub holly
- Ilex opaca var. opaca, holly
- Ilex verticillata, winterberry
- Ilex vomitoria, yaupon holly
- Ilex xattenuata, Palatka holly
- Illicium floridanum, Florida anise, purple anise
- Illicium parviflorum, yellow star anise
- Impatiens capensis, spotted touch-me-not
- Impatiens wallerana, impatiens
- Imperata cylindrica, cogon grass
- Indigofera caroliniana, wild indigo, Carolina indigo
- Indigofera hirsuta, hairy indigo
- Indigofera spicata, creeping indigo
- Ionactis linariifolia, stiff-leaved aster
- Ionopsis utricularioides, delicate ionopsis
- Ipomoea alba, moonflower
- Ipomoea aquatica, waterspinach
- Ipomoea cairica, Cairo morningglory, mile-a-minute vine
- Ipomoea carnea subsp. fistulosa, shrubby morningglory, bush morning-glory
- Ipomoea cordatotriloba, sharppod morningglory, tievine
- Ipomoea hederacea, ivyleaf morningglory
- Ipomoea hederifolia, scarlet morningglory
- Ipomoea imperati, beach morningglory
- Ipomoea indica var. acuminata, oceanblue morningglory
- Ipomoea pandurata, wild potatovine, manroot, man-of-the-earth
- Ipomoea pes-caprae subsp. brasiliensis, railroadvine, lavender goatfoot morning-glory
- Ipomoea purpurea, common morningglory
- Ipomoea quamoclit, cypressvine
- Ipomoea sagittata, saltmarsh morningglory
- Ipomoea triloba, littlebell morningglory
- Ipomopsis rubra, standing-cypress
- Iresine diffusa, bloodleaf
- Iris hexagona, prairie iris
- Iris tridentata, bay iris, dwarf iris
- Iris virginica, Virginia iris, southern blue-flag
- Isoetes flaccida, Florida quillwort
- Itea virginica, Virginia-willow
- Iva frutescens, bigleaf marsh-elder
- Iva imbricata, seacoast sumpweed
- Iva microcephala, piedmont marsh-elder