INDEX 



365 



Plant fibers, 312-314 



Plant geography, 197 



Plant industries, *308~332 



Plant lice, 328, 330 



Plantain, flowers of, 152* 



Plant-breeding rules, 190, 191 



Plasmopara, 239*, 2(31 



Plastid, 37* 



Pleurococcus, 221, 222*, 223, 249, 260 



Plum, black knot of, 247 



Plums, 187* 



Plumule, 158*, 160*, 162* 



Poison ivy, 73* 



Pollarding, 98* 



Pollen, 15, 128*, 129*, 130*, 134*, 



135* 



Pollen, discharge of, 128*, 129* 

 Pollen chamber, 129* 

 Pollen grain, germination of, 135*, 



301* 



Pollen sac, 129* 

 Pollen tubes, 16, 135*, 136*, 291* 



300 



Pollen-carrying, 139 

 Pollen-carrying apparatus, 146*, 150* 

 Pollination, * 134-1 54, 290 

 Pollution of water supply, 229 

 Polyporus, 234*, 235*, 261 

 Pond lily, 78* 



Pondweed, section of stem of, 85* 

 Potato, 87*, 88*, 145* 

 Potato blight, 240*-242 

 Preservation of fruits, 208, 209 

 Pressure of water, 24 

 Privet, branching of, 97* 

 Propagation by cuttings, 90 

 Propagation by roots, 32* 

 Propagation by seeds, *161-171 

 Proteins, 17, 39, 43, 159, 183, 184 

 Protonema, 263*, 266 

 Protoplasm, 21, 22 

 Protoplast, 21 

 Pruning, 317*, 318* 

 Pruning due to shade, 77-79 

 Pteridophytes, 261, *269-281 

 Pteridophytes, classification of, 281 

 Pteridophytes, evolution of, 306 

 Pteris, 271* 

 Ptomaines, 209 

 Public health, 212-218 

 Puccinia, 255*, 256, 261 

 Puffball, 259*, 260 

 Pulvinus, 77 



Quercus, 194, 195*, 196 



Eadial symmetry, 129 



Raspberry, 89*, 157*, 171* 



Receptacle, 126* 



Red algae, 232*, 233, 261 



Red clover, leaf of, 77* 



Redwood, 294 



Reindeer moss, 251 



Reproduction, sexual, in flowering 



plants, *134-137, *289-292, *299- 



303 



Reproduction, of bacteria, 201-203 

 Reproduction, by portions of stem, 



*87-92 



Reserve food in seeds, 158, 159, 165 

 Resin duct, 285* 

 Respiration, 46, 47 

 Resting buds, 94 

 Rest period in seeds, 162 

 Rhizoids, 236 

 Rhizome. See Rootstock 

 Rhizopus, 260 

 Rhodophycese, 260 

 Ring, annual, 12*, 66 

 Rise of water in stems, 42, 43 

 Rockweed, 231* 

 Roguing, 177 

 Root, 8*, 9, 10*, 11* 

 Root, fleshy, 45* 

 Root, section of, 11*, 20* 

 Root absorption, 9 

 Root climbers, 73*, 74 

 Root hairs, 9, 10*, 11*, 21* 

 Root system, 25 

 Root tubercles, *203-207 

 Rootcap, 20 

 Roots, aerial, 30*, 31 

 Roots, air requirements of, 26*-28 

 Roots, anchorage by, 8*, 9 

 Roots, earth, 25-29 

 Roots, effects of, on soil, 26, 27 

 Roots, parasitic, 31 

 Roots, pull of, 25, 26 

 Roots, reproduction by, 32* 

 Roots, storage of food and water in, 



45* 



Roots, structure of. 20*, 21* 

 Roots, water, 29*-31 

 Roots, water-lifting by, 24 

 Rootstock, 86*, 87, 271, 272* 

 Root-tubercle bacteria *205-207 

 Roquefort cheese, 245 

 Rose, leaf bud of, 94* 

 Rosette plants, 72*, 73 

 Runners, 90 

 Run-off, 119, 120 



