INDEX 



541 



Penicillium, 223, 231* 



Perennial, 12, 33, 35 



Perianth, 109 



Perigynous, 114 



Perisperm, 136 



Peronospora, 223 



Petal, 20*, 105* 



Petiole, 13 



Peziza, 226, 227 



Pfeffer, W., 389 



Phseophycese, 206 



Phallus, 254* 



Phanerogams, 323 



Phloem, see Bast 



Phosphorus, 15, 448 



Photosynthesis, 15-17, 39, 40, 181 



Phycomycetes, *213-225 



Phylloxera, 463, 464 



Physiology, 159 



Phytopathology, 159 



Phytophthora, 222, 223 



Pine forests, 299 



Pine needle, 300, 302*, 303* 



Pine seed, 309* 



Pine stem, growth of, 44, 51, 52 



Pine wood, section, 390* 



Pineapples, 348* 



Pinesap, 382* 



Pinus, *299-309, 314 



Pistil, 20*, 21*, 111, 112* 



Pistillate flower, 106*, 108* 



Pitcher plants, 386, 387* 



Pith, 11, 12* 



Placenta, 112* 



Plains region, 505-507 



Plant associations, 495, 496 



Plant breeding, *412-433 



Plant cell, 7, 8 



Plant fibers, 47*, 48* 



Plant food for domestic animals, 2 



Plant formations, 495 



Plant geography, *495-513 



Plant industries, *434-464 



Plant lice, 372, 373 



Plantain, flowers of, 131* 



Plants as fertilizers, 36, 37 



Plasmopara, *219-222 



Plastid, 14* 



Pleurococcus, 188, 189*, 190 



Plowrightia, 234 



Plum, black knot, 234 



Plums, 430*, 462 



Plumule, 136* 



Poison ivy, 60* 



Pokeweed, 473* 



Pollen, 115*, 307, 325 



Pollen, discharge of, 111* 



Pollen chamber, 110* 



Pollen grain, germination of, 115 



116*, 117*, 308, 325, 326* 

 Pollen sac, 110*, 111, 307* 

 Pollen tubes, 116*, 117*, 308*, 326* 

 Pollen-carrying apparatus, 123*, 



129* 



Pollination, *115-135, 307, 326 

 Pollution of water supply, 169, 174, 



177, 205, 206 

 Polyporus, *251-253 

 Polytrichum, 265 

 Pome fruits, 459, 460 

 Pond lily, 67*, 478* 

 Pondweed, section of stem of, 479* 

 Poplar bud, section of, 96* 

 Position of buds, 92* 

 Postelsia, 208 

 Potassium, 15, 448 

 Potato, 365, 366, 413*, 453* 

 Potato blight, 222, 453* 

 Prairies, 506, 507 

 Preservation of fruits, 168, 169 

 Prickly-pear cactus, 81* 

 Pronuba, 128*, 129* 

 Propagation by cuttings, 86 

 Propagation by roots, 33* 

 Propagation of seed plants, 33*, *82- 



89, *139-144 

 Proteins, 17, 35, 77, 80, 138, 144, 419- 



421 



Protonema, 257, 259 

 Protoplasm, 8*, 181 

 Protoplasm, structure of, 181 

 Pruning, 451-453 

 Pruning, due to shade, 42* 

 Pteridophytes, 158, *2 74-298 

 Pteridophytes, classification of, 298 

 Pteridophytes, evolution of plants, 



330, 334 

 Pteridophytes, summary of, 297, 



298 



Pteris, 275* 

 Ptomaines, 170 

 Public health, 161-179, 169, 174, 177, 



205, 206 



Puccinia, *243-246 

 Puffball, 240, 253, 254 

 Pulvinus, 65 

 Pythium, 223 



Quercus, 157*, 158 

 Quince, 460 



