New York, 270.
Nicotiana Tabacum, 223.
North Carolina, 288.
North Dakota, 342.
Nymphaea advena, 52.
Nyssa — acuminata, 227; aquatica, 226; biflora, 226; Ogeche, 227; sylvatica, 226; uniflora, 226.
Oak, 46.
Ogeche lime, 227; plum, 227.
Ohio, 318.
Oklahoma, 352.
Olea europea, 46.
Olive, 46.
Onion, 175.
Onobrychis sativa, 200.
Opuntia Engelmanii, 86.
Orange, 175-177.
Orange Hawkweed, 177.
Oregon, 384.
Oregon Grape, 177.
Oreocarya, 177; virgata, 179.
Oreodoxa regia, 179.
Origanum vulgare, 159.
Oxydendrum arboreum, 204.
Palm, 179; utilized by natives, 179; Talipot, 179; Cocoanut, 179; Royal, 179. Palmacea, 179.
Palmetto — cabbage, 179; saw, 181; scrub, 181. Palo Verde, 183.
Papaver, 48; somniferum, 48.
Paradise Flower, 90.
Parkinsonia aculeata, 144; torreyana, 183.
Parsnip, 183.
Partridge-pea, 184.
Pastinaca sativa, 183.
Pea, Sensitive. See Partridge-pea.
Peach, 186.
Peanut, 186; honey won blue-ribbon prize, 186.
Pear, 186.
Pectis papposa, 187.
Pennsylvania, 274.
Pennyroyal, 187.
Pentstemon laevigatus, 70.
Pepperbush. See Clethra.
Pepperidge. See Tupelo, 226.
Peppermint. See Mint.
Pepper-vine. See Cow-itch, 117.
Pepperwood. See Prickly Ash, 190.
Persea Borbonia, 194.
Persimmon, 187.
Petalostemum, 190.
Phacelia, 187; hispida, 188; tanacetifolia, 187.
Phaseolus, 69; lunatus, 147; multiflorus, 69; vulgaris, 69.
Phoenix dactylifera, 44.
Phoradendron flavescens, 169.
Pigeonberry, 80.
Pigeon Cherry, 188.
Pin Clover. See Alfilerilla, 60.
Pink-vine, 188.
Pistillate Flowers, 39.
Plantago, 48; ignota, 48; aristata, 48.
Plantain, 48.
Plant-lice, 32; Cared for by Ants, 33.
Plants Valuable for Pollen, 39.
Pluchea — petiolata, 156; sericea 156.
Plum, 188; Canada, 188; wild goose, 188; chicasaw, 188; sand, 188; beach 188; hog, 188.
Poinsettia, 190.
Poison Ivy or Oak. See Sumac, 210.
Poison Laurel. See Mountain Laurel.
Poisonwood, 210.
Pollen Famines, 23.
Pollen-Flowers, 23; Two Groups of, 25, 39; Erroneously Reported to Yield Nectar, 25, 27.
Pollen Necessary for Brood-rearing, 23.
Pollen-plants Not All Pollinated by Insects, 39.
Pollen, Where Produced Abundantly, 25.
Pollination, Cross, 4.
Polygonum — Persicaria, 136; acre, 137; Bolanderi, 137; lapathifolium; sachalinense, 195.
Poplar. See Tulip Tree, 48, 190.
Poppy, 48.
Poppy, California, 41.
Populus, 48; angustifolia, 48; balsamifera, 48.
Porliera angustifolia, 204.
Prairie Clover, 190.
Prickly Ash, 190.
Prickly Pear. See Cactus.
Privet 190.
Prosopis — Glandulosa, 160; juliflora, 164; velutina, 160.
Prune. See Plum, 188.
Prunus — armeniaca, 63; avium, 96; Amygdalus, 60; Cerasus, 96; hortulana, 188; Nigra, 188; pennsylvanica, 188; persica, 186; umbellata, 188; virginiana, 96.
Psedera quinquefolia, 243; tricuspidata, 78.
Psoralea, 190; tenuiflora, 190.
Ptelea trifoliata, 142.
Pumpkin, 190.
Purple-flowered mint, 190.
Purple Sage. See Sage.
Purple Thistle, 191.
Pycnanthemum virgianum, 67.
Pyrus communis, 186; Malus, 63.
Queen of the Meadow. See Boneset.
Quercus, 46; alba, 46; rubra, 46; virginiana, 46.
Rabbit-brush, 191.
Radish, 191.
Ragweed, 48.
Rainfall, Influence of on Nectar Secretion, 16.