203 INDEX. 



Oosphere, of Angiosperms, 125 ; of Gymnosperms, 133 ; of ferns, 143 ; 



of Vauoheria, 151 ; of Fuous, 149 ; of Bryophyta, 145, 146. 

 Oospore, see Oosphere. 



Optimum temperatxire, 160 ; illumination, 181. 

 Organic material. Absorption of, by fimgi, 89. 

 Osmosis, 49, 64, 172, 189. 

 Osmotic equilibrium, 12, 172, 189. 

 Oxalic acid, Oocxirrence of, in plant-oeUs, 84, 171 ; as a bye-product during 



metabolism, 84, 159, 171. 

 Oxidation, 12, 44, 157, 159, 161, 165, 187. 

 Oxygen, Evolution of, during assimilation, 13, 18, 27, 165, 178 ; essential 



to respiration, 30, 160, 178 ; essential to formation of chlorophyll, 



169 ; essential to katabolic constructive processes, 159 ; essential to 



mitosis, 103. 



Palisade cells, 36, 37. 



PalmeUa stage, 98. 



Parenchyma, Definition of, 4. 



Parauuclein, 103. 



Parthenogenesis, in Chara crinita, 155. 



Pectose, in young cell-waU, 25, 44 ; in middle-lamella, 44. 



Pelargonium, Glandular hair of, 33. 



Peperomia, AnomaUes in maturation stages of, 155. 



Peptic ferments, see Enzymes. 



Peptones, occurrence in plants, 171. 



Periblem, 24. 



Pericyole, 37, 46, 77. 



Phanerogams, Position of, 6. 



Phelloderm, 39. 



PheUogen, see Cork-cambium. 



Phloem, Origin of, 49, 51, 60 ; Functions of, 64. 



Phosphorus, in nucleus, 7, 103 ; as phosphates in ceU-sap, 171 ; in aleuione. 



grains, 176 ; as an essential element in plants, 157. 

 Photosynthesis, 18, 165, 167, 177, 180 ; Sugars formed during, 160, 165, 



180. 

 Phototonus, 181. 

 PhyUooyanin, 165 

 PhyEoxanthin, 165. 

 Pinus, Bordered-pits in stem of, 66, 68 ; Medullary rays of, 74 ; Tracheides 



of, 66, 68, 71 ; Reproduction in, 130, et seq. ; Resin-canals of, 79, Sil. 



et seq. 

 Pith, see Medulla. 



Pits, Simple, 26, 41, 45, 65 ; Bordered, 66, 68 ; Origin of bordered, 6S. 

 Plant characteristics, 97, 98. 

 Plasmodium, of Amoeba, 1, 8 ; of AethaUum, 8. 

 Plasmolysis, in VaUisneria, 16 ; in Spirogyra, 91 ; in Vaucheria, 95. 

 Plasmosome, see Niicleolus. 

 Plastic materials, see Starch, Proteids, Protoplasm, Cellulose Wood. 



