672 



Persian clover, 433 



tobacco, 600 

 Persicaria, 286 

 Peruvian alfalfa, 447 

 Petals, 48 

 Petiole, 42 

 Petunia, 559 

 Phaeophycese, 63 

 Phaseolus, 421 



angularis, 423 



aureus, 423 



key to principal species of, 423 



lunatus, 423, 424 

 macrocarpus, 424 



multiflorus, 423 



vulgaris, 423, 426 

 nanus, 426 

 Phleum, 222 



alpinum, 223 



pratense, 222 

 Phloem, 18, 35 



elements, functions of, 36 



parenchyma, 35 

 Photosynthesis, 46 

 Phycomycetes, 64 

 Phylloxera, 499 

 Phylogeny, 83 

 Physalis, 559 

 Pickles, 621 

 Pie plant, 286 

 Pileole, 104 

 Pistil, 48, 51 



Pistillate inflorescence, 55 

 Pisum, 416, 417 



sativum, 418 

 Pitcher plants, 47 

 Pitching, 150 

 Pith, 18, 39 

 Placenta, 50 

 Placentation, 53 

 Plant body, i 



fundamental internal structure of, 4 



cell, 4 



Plant body, cell, discovery of, 4 

 structure of, 6 



nomenclature, 64 

 Plastids, chloroplastids, 8 



chromoplastids, 8 



leucoplastids, 8 

 Plerome, 17 

 Plum, American, 397, 400, 401 



Chicasaw, 401 



family, 391 



hortulana, 400 



Japanese, 400 



key to principal species of, 397 



myrobalan, 400 



old world, 397 



tomato, 590 

 Plumy asparagus, 246 

 Poa pratensis, 70 

 Poaceae, 69 

 Pod, 58 



corn, 178, 180 

 Polar nuclei, 50 

 Polish wheat, in, 112, 113 

 Pollen grains, 48, 52 



mother cells, 50 



tube, 52 

 Pollination, 51 

 Polygonaceae, 284 



key to principal genera, 286 

 Polygonum, 284 

 Pomaceae, 366 



key to important genera of, 367 

 Pome, 366 

 Pomelo, 485 

 Poncirus, 476, 489 



trifoliata, 489 

 Pop corn, 178, 180 

 Poppy family, 326 

 Pot-herb mustard, 340 

 Potamogeton, 29 

 Potato, 561 



family, 559 



onions, 241 



