INDEX. 



733 



Opuntia, 559 

 Opuntiales, 708 

 Orchidaceae, 665, 703 

 Orchidales, 665, 703 

 Orchids, 442 

 Oscillatoria, 589 

 Oscillatoriaceae, 163 

 Osmosis, 1320 

 Osmundaceas, 295 

 Ostrich fern, 279 

 Ovule, 302, 321, 334, 421 

 Oxalis, 707 

 Oxycoccus, 709 

 Oxydendrum arboreum, 709 

 Oxygen, 63, 110-113 



Pacific forests, 538 



Palisade cells, 41, 43 



Palmaceae, 702 



Palmales, 702 



Palms, 408 



Palustrine forest, 537 



Pandanales, 702 



Panicum scribnerianum, 559 



Pandanus, 702 



Pandorina, 160, 350 



Panicle, 427 



Panicum amarum, 599 



Panicum halophilum, 599 



Panicum repens, 599 



Papaverales, 652, 676, 706 



Papilionacese, 423, 682, 707 



Parasites, 83, 84, 86, 527, 628 



Parasitic fungi, nutrition of, 86-90 



Parenchyma, 50, 356, 363 



Parietales, 687, 708 



Parkeriaceas, 296 



Parmelia, 96 



Parmelia contigua, 602 



Parsley family, 692 ; ^carrot family, 



Parthenogenesis, 184 [78 



Partridge berry, 711 



Pea, 683, 707 



Pea family, 682, 707 



Pear, 456, 682 



Peat moors, 578, 607 



Peat moss, 608 



Pediastrum, 161 



Pelagic plant societies, 627-629 



Pellia, 164 



Pellonia, 405 



Peltigera, 94, 95 



Pepo, 456 



Pericycle, 360 



Peridineae, 166 



Perigynous, 425 



Perisperm, 331, 332 



Perisporiales, 217 



Peronospora, 183, 215 



Peronosporales, 215 



Persimmon, 710 



Peucedanum fceniculaceum, 562 



Peucephyllum schattii, 571 



Pezizales, 217 



Phacidiales, 217 



Phaeophyceae, 167 



Phaeosporales, 171 



Phallales, 219 



Phloem, 5052, 360, 361, 363 



Phlox family, 710 



Phoradendron flavescens, 84, 705 



Photic region, 621, 628 



Photosynthesis, 67, 68, 70, 117, 622 



Phycomycetes ( Phy"co-my-ce / tes) , 



214, 215 

 Phyllidium, 371 



Phylloclades, 373, 395 



Phyllotaxy, 375, 384 



Physical condition of soil, 475, 476 



Physical factors, 465-476 



Physiography, 479 



Phytolaccaceae, 705 



Phytomyxa leguminosarum, 92 



Phytophthora, 182, 184, 215 



Pickerel weed, 626, 703 



Pilularia, 296, 627 



Pinales, 216, 653 



Pine, white, 297-310 



Pinguicula vulgaris, 610 



Pinus divaricatus, 602 



Pinus scopularum, 560 



Pinus strobus, 602, 653 



Piperales, 704 



Pisum sativum, 683 



Pitcher-plant, 610, 706 



Pith, 50 



Plains' formations, 559 



Plankton, 621 



Plant -food, sources of, 81 



Plant-formations, 515-528 



Plant-substance, analysis of, 79, 80 



Plantaginales, 711 



Plantago, 711 



Plasmolysis (plas-mol'y-sis), 19 



Plasmopara, 183, 215 



Plectascales, 217 



Plectobasidiales, 220 



Pleurococcaceae, 161 



