epeta, 98

Nettle, 24

Nettle, Dead, 99

Nettle Family, 23

Nettle, Hedge, 99

Nettle, Hemp, 99

Nettle, Horse, 100

Nicandra, 101

Nicotiana, 101

Nigella, 38

Nightshade, 100

Nightshade, Enchanter's, 78

Nightshade Family, 100

Ninebark, 53

Nipplewort, 115

Nodding Pogonia, 18

Norway Pine, 1

Nut Grass, 8

Nyctaginaceae, 31

Nymphaea, 35

Nymphaeaceae, 35

Nymphoides, 88

Nyssa, 83

Oak, 22, 23

Oakesia, 12

Oats, 6

Oenothera, 78

Oleaceae, 88

Oleaster Family, 77

Olive Family, 88

Onagraceae, 78

One-flowered Wintergreen, 85

Onion, Wild, 13

Onosmodium, 93

Opuntia, 77

Orache, 29

Orchard Grass, 6

Orchidaceae, 15

Orchis, 17

Orchis, Crane-fly, 16

Orchis Family, 15

Orchis, Showy, 17

Ornithogalum, 14

Orobanchaceae, 106

Orobanche, 106

Orpine Family, 48

Osmorhiza, 82

Ostrya, 22

Oswego Tea, 96

Oxalidaceae, 64

Oxalis, 64

Ox-eye, 123

Ox-eye Daisy, 131

Oxybaphus, 31

Oxypolis, 81

Painted Cup, 102

Painted Trillium, 12

Pale Violet, 76

Panax, 80

Panic-grass, 5

Panicum, 5

Pansy, 76

Papaveraceae, 41

Papaver, 41

Papaw, 40

Paper Birch, 21

Parietaria, 24

Parnassia, 50

Parsley Family, 80

Parsley, Hemlock, 83

Parsnip, Cow, 82

Parsnip, Meadow, 81

Parsnip, Prairie, 81

Parsnip, Water, 81

Parsnip, Wild, 81

Partridge Berry, 108

Partridge Pea, 60

Pasque Flower, 38

Pastinaca, 81

Patience Dock, 26

Pea, 59

Peach-leaved Willow, 20

Pear, 54

Pear, Prickly, 77

Pearlwort, 32

Pearly Everlasting, 120

Pedicularis, 102

Pellitory, 24

Peltandra, 9

Penny Cress, 46

Pennyroyal, 95

Pennywort, Water, 80

Penthorum, 49

Pentstemon, 104

Pepper Family, 19

Pepper Grass, 46

Peppermint, 98

Perfumed Cherry, 54

Periwinkle, 90

Petalostemum, 60

Petasites, 130

Petunia, 101

Phacelia, 93

Phleum, 4

Phlox, 92

Phragmites, 6

Phryma, 107

Phrymaceae, 107

Physalis, 101

Physocarpus, 53

Physostegia, 99

Phytolacca, 30

Phytolaccaceae, 30

Picea, 1

Pickerel-weed, 10

Pickerel-weed Family, 10

Picris, 115

Pignut Hickory, 21

Pigweed, 30

Pilea, 24

Pimpernel, 87

Pimpernel, False, 104

Pimpernel, Water, 87

Pinaceae, 1

Pin Cherry, 54

Pine, 1

Pine Drops, 84

Pine Family, 1

Pineweed, 74

Pinguicula, 105

Pink, Deptford, 34

Pink Family, 31

Pink, Fire, 33

Pink, Meadow, 34