INDEX 



201 



Pea, 181, 182 



Peduncle, 112 



Perennial, 55, 104, 105, 107, 110, 189, 191 



Petal, 113-115, 116 



Petiole, 72 



Petunia, 112, 114, 115, 117 



PH, 109, 159, 166, 171-173, 177 



Phenotype, 135 



Phloem, 34, 54, 55 



Phosphorus, 159, 164-170, PI. XIII 



Photoperiodism, 84, 85 



Photosynthesis, 75-85, 96 



rate of, 80, 82 

 Pistil, 113-115, 116, 117 

 Pitcher plant, 77 

 Pith, 54, SS 

 Plant ash, 164 

 Plant breeding, 138 

 principles of, 123 

 Plant disease, 97-102 

 leaf infection, 99 

 radish leaf, 100 

 Plantain, 110 

 Plastids, 25 

 Plowing, 158 



Plumule, 8, 9, 11, 53, PI. I 

 Pollen, 116-119 

 Pollen-sac, 114 

 Pollination, 116, 118, 119 

 Polyploid plants, 26, PI. IX 

 Polyploidy, 146-148 

 Poison, 43, 44, 98, 99, 162, 164 

 Poison ivy. 111 



Potassium, 44, 45, 159, 164-170 

 Propagation, 66-71 

 asexual, 66-71 

 budding, 70 

 clone, 67 

 cutting, 67, 68 

 grafting, 68-70, 70, PI. IV 

 layering, 71 

 sexual, 66 

 Protein, 41, 42, 80 



Protoplasm, 2, 21, 23-25, 42, 43, SO, 184 

 Pruning, 57-65 

 defined, 59 

 reasons for, 59, 94 

 suckering, 61, 62 

 thinning, 60, 62 



time, 62, 64 

 training, 59 

 vigor, 64 

 wounds, 63 



Quick lime, 171 



Q 



R 



Radicle, <?, 9, 11 

 Radish, 181, 182 

 Radish leaf, infected, 100 

 Ray flower, 113, 118 

 Recessive characteristics, 125 

 Recombinations, 128, 135, 136 

 Reduction division, 28, 131-134 

 Reproduction, 66-71, 84, 85 

 asexual, 66-71 

 sexual, 66, 67 

 weeds, 105-107 

 Respiration, 83 

 Rest period, 188-192 

 Rhizocauline, 156 

 Rhododendrons, 171 

 Ringing, 63 

 Root, 30-40 

 adventitious, 32 

 balance of, 92-96 

 cross section, 34 

 food storage, 37 

 function of, 33 

 growth, 39, PI. X 

 growth area of, 36 

 hairs, 33, 34, 35, 36, 38, 43 

 longitudinal section, 35 

 lima bean, 31, 32 

 oats, 12 



parts of, 30, 31, 34 

 primary, 30 

 secondary, 30 

 systems, 30, 158 

 tap, 30, 31 

 tip, 36 

 Root pruning, 94, 95 

 Rose, 115, 116 

 multiflora, 191 

 pruning, 63, 94 

 Rotation of crops, 161 



