Hawkweed, 116, 117 Hazel, 22 Heather, False, 74 Heath Family, 84 Hedeoma, 95 Hedge Hyssop, 104 Hedge Mustard, 44 Hedge Nettle, 99 Helenium, 127, 128 Helianthemum, 74 Helianthus, 128-130 Heliopsis, 123 Hemerocallis, 11 Hemlock, 1 Hemlock, Ground, 2 Hemlock Parsley, 83 Hemlock, Poison, 83 Hemlock, Water, 82 Hemp, 24 Hemp, Indian, 90 Hemp Nettle, 99 Hemp, Water, 30 Hemp Weed, 131 Henbane, 101 Hepatica, 38 Heracleum, 82 Herb Robert, 64 Herb Sophia, 43 Hercules' Club, 80 Hesperis, 47 Heteranthera, 10 Heuchera, 50, 51 Hibiscus, 72 Hickory, 21 Hieracium, 116, 117 Hill's Oak, 23 Hippuris, 79 Hoarhound, 96 Hoarhound, Water, 95 Hobble-bush, 111 Hog Peanut, 59 Holly Family, 69 Holly, Mountain, 69 Honewort, 82 Honey Locust, 58 Honeysuckle, 110 Honeysuckle, Bush, 110 Honeysuckle Family, 109 Hop, 24 Hop Clover, 60 Hop Tree, 65 Hordeum, 4 Hornbeam, 21 Horned Pondweed, 2 Hornwort, 34 Hornwort Family, 34 Horse Balm, 95 Horse Chestnut, 70 Horse Mint, 96 Horse Nettle, 100 Horse Radish, 46 Horse Weed, 130, 131 Hound's Tongue, 93 Houstonia, 108 Huckleberry, 86 Hudsonia, 74 Humulus, 24 Hyacinth, Wild, 14 Hybanthus, 75 Hydrocharitaceae, 3 Hydrocotyle, 80 Hydrophyllaceae, 93 Hydrophyllum, 93 Hyoscyamus, 101 Hypericaceae, 73 Hypericum, 73, 74 Hypoxis, 14 Hyssop, 98 Hyssop, Hedge, 104 Hyssopus, 98 Ilex, 69 Illecebraceae, 31 Ilysanthes, 104 Impatiens, 71 Imperatoria, 82 Indian Cucumber-root, 13 Indian Currant, 110 Indian Hemp, 90 Indian Mustard, 44 Indian Pipe, 84 Indian Plantain, 122 Indian Tobacco, 113 Indian Turnip, 8 Indigo, Wild, 61 Inula, 127 Ipomoea, 92 Iridaceae, 15 Iris, 15 Iris Family, 15 Ironweed, 122 Ironweed, Yellow, 128 Ironwood, 22 Isopyrum, 39 Iva, 114 Jack Pine, 1 Jeffersonia, 40 Jerusalem Artichoke, 129 Jerusalem Oak, 29 Jimson Weed, 100 Joe-Pye Weed, 122 Jointweed, 27 Juglandaceae, 21 Juglans, 21 Juncaceae, 10 Juncaginaceae, 3 Juncus, 10 Juneberry, 55 Juniper, 1 Juniperus, 1 Kalmia, 85 Kenilworth Ivy, 103 Kentucky Coffee-tree, 58 King-nut Hickory, 21 Knapweed, 121 Knawel, 31 Knotweed, 26, 27 Knotwort Family, 31 Kochia, 28 Koeleria, 6 Krigia, 115 Kuhnia, 122 Labiatae, 95 Labrador Tea, 85 Lactuca, 115, 116 Ladies' Tresses, 16 Lady's Slipper, 18 Lake Cress, 45, 46 Lamb's Quarters, 29 Lamium, 99 Laportea, 24 Lappula, 94 Lapsana, 115 Large-toothed Aspen, 19 Larix, 1 Larkspur, 36 Lathyrus, 59 Lauraceae, 41 Laurel Family, 41 Lead Plant, 58 Leafcup, 123 Leatherleaf, 86 Leatherwood, 77 Lechea, 74, 75 Ledum, 85 Leek, Wild, 13 Leersia, 5 Leguminosae, 58 Lemna, 9 Lemnaceae, 9 Lentibulariaceae, 105 Leontodon, 115 Leonurus, 98 Lepachys, 128 Lepidium, 45, 46 Lespedeza, 61, 63 Lettuce, 115, 116 Lettuce, Wild, 115, 116 Liatris, 121 Lilac, 88 Liliaceae, 10 Lilium, 12 Lily, 12 Lily Family, 10 Lily of the Valley, Wild, 12 Lily, Pond, 35 Lily, Water, 35 Limnanthaceae, 68 Limosella, 103