INDEX. 203 



Plastids, in young cell, 19 ; in rhizome of Iris, 163 ; Starch-formation in, 

 21, 163 ; Fat-formation in, 160. 



Polarised hght. Use of, in studying starch-structure, 162. 



Pollen-tube, Growth of, 127, 186 ; Formation of, 121, 132, 137. 



Polyembryony, 138. 



Potassium, as essential element in plants, 157. 



Potato, Starch-grains in, 162 ; Cork of, 38. 



Procambial strands, 50. 



PromyceUum, 147. 



Prophase, see Mitosis. 



Prosenchyma, Definition of, 4. 



Proteids, Manufacture of, 169, 177 ; Storage of, 170, 176, 177. 



Proteus vulgaris. Attraction of, by oxygen, 182. 



Prothallial cell, in microspore of Angiosperms, 121 ; in microspore of 

 Gymnosperms, 132. 



ProthaUium, of Angiosperms, 154 (see Table opp. p. 1.54) ; of Gymnosperms, 

 132 ; of ferns, 142, 144. 



Prothallus, 118, 142, 144. 



Protonema, 145. 



Protophloem, 51. 



Protoplasm, Definition of, by Huxley, 7 ; Composition of, 7, 10 ; Move- 

 ments of, 8, 9, 11, 15 ; Rotation of, 15 ; Staining of, 17 ; Growth of, 

 21 ; Conditions essential to continued activity of, 12 : Water of con- 

 stitution of, 10 ; Solvents of, 12 ; Effects of nhvsical and chemical 

 stimuli upon, 184. 



Protoplast, Definition of, 1. 



Protosylem, 50, 69. 



Prussic acid. Assimilation of, 170. 



Pseudopodia, of Amoeba, 2, 8 ; of Diatoms, 99 



Pteridophyta, Reproduction in, 118, 119, 140, 144 ; Position of, 6. 



Pulvinus, 185. 



P\Tenoids, of Spirogyra, 90 ; of SphsreUa, 97. 



Q 



QuEECTJS, for study of wood-elements, 71 ; cork-layers in Q. sessiliflora, 39. 

 Quiescent nucleus, 101. 

 Quinine, see Alkaloids. 



Radial, sections, 74 ; wall-formation in cambium, 46. 



Pvaphides, in Dracaena, 82, 84 ; Composition of, 84. 



Reproduction, general considerations, 117, 118, 119. 



Resin, Formation of, 83, 172. 



Resin-canals, in Pinus, 79, 80, &t seq. ; Development of, 81, 83. 



Respiration, Products of, 12, 30 ; Oxygen essential to, 12, 30, 159, 179 ; 



Anaerobic, 179. 

 Resting-stage, in spore of Vaucheria, 95, 153. 

 Reticulate vessels, 66, 71. 

 Rhododendron, Glandular hairs of, 33. 



