806 



INDEX 



Nitrification, 533, 537 



Nitrites, 533 



Nitrobacter, 533 



Nitrogen, 142, 177, 190, 328, 531, 593; 

 cycle, 537, 538 



Nitrogen-fixation, 534. 538, 709; non- 

 symbiotic, 537; symbiotic, 537 



Nitrosococcus, 533 



Nitrosomonas, 533 



Node, 246, 247, 271 



Nodules, 535, 709 



Non-green cells, 132; plants, 101, 504- 

 514 



Nucellus, 684 



Nucleus, 59, 60, 64; composition of, 65: 

 endosperm, 376; fusion, 374, 376, 450; 

 generative, 372; triple-fusion, 376, 

 450; tube, 372 



Oak, 508, 754, 757. 789; family, 704; 



flowers, 705 

 Oceans, 598; life in. 601 

 Octoploid, 478 

 Oedogonium, 616, 618, 636 

 Offsets, 411 

 Oils {see Fats) 

 Oleaceae, 714 

 Olive family, 714 

 Onion root tip, 447; "sets," 410 

 Oogonium, 547, 618 

 Oospore, 618 

 Oparin, 529 

 Operculums, 644, 648 

 Ophioglossum, 665 

 Opuntia, 85 

 Orchid, 119, 507; family, 701; flowers, 



702, 703 

 Orchidaceae, 701 

 Ordovician period, 723 

 Osmosis, 199, 201, 204, 320; and plant 



behavior, 209-220 

 Osmiinda, 665 

 Overgrowths, 573 

 Overturns, 594, 595 

 Ovulary, 354, 373 

 Ovulate cones, 683, 684 

 Ovule, 336, 353, 373, 375, 688 

 Oxidation, 98, 110, 155 

 Oxidation-reduction, 99, 138, 143, 152, 



156, 168 



Oxygen, 96, 108, 152, 177, 310, 518, 

 589, 592; deficiency, 161 



Paleozoic floras, 727 



Palisade layers, 72 



Fallavicinia, 654 



Palm, 85, 698, 772; family, 697 



Palmaceae, 697 



Pandaniis, 297 



Panicle, 360, 361 



Papilionaceae, 708 



Parasites, 31, 505, 506, 507, 551, 572; 

 facultative, 506; obligate, 506 



Parenchyma, 72, 272; cortical, 264; 

 phloem, 283; xylem, 284 



Parthenocarpy, 380 



Parthenogenesis, 380 



Pasteur, 527 



Pasteurization, 525 



Pathogen, 568 



Patrician center, 734 



Pea family, 708; flower, 354, 355; gar- 

 den, 355, 459, 462 



Peach, brown-rot of, 578 



Peach-leaf curl, 572, 579 



Peanuts, 709 



Pearl bush flowers and fruits, 362 



Peat, 651; moss, 645, 649 



Pectase, 175 



Pectic acid, 171, 175; compounds, 65, 

 169, 170 



Pectin, 171, 175 



Pectinase, 175 



Pectose, 170, 175 



Pectosinase, 175 



Peduncle, 353 



Penicillium, 548, 550 



Pepper flower development, 336 



Peptase, 175 



Peptones, 175 



Perennials, 33, 46 



Perianth, 354 



Pericarp, 361 



Pericycle, 264, 266, 282, 304; fibers, 264, 

 281 



Periodicity, 32, 611, 612 



Perisperm, 380 



Peristome, 644, 648 



Periwinkle, leaf section of, 71 



Permeability, 205 



Personification, 51 



