2go 



INDEX 



of light on buds of, 94 ; P. pyramidalis, 



polarity of, 158. 

 Post-regeneration, 170. 

 Potamogeton natans, causes of elongation 



of, 128. 

 Potassium, influence of, on germination of 



spores, 113. 

 Potato, disappearance of resting period in, 



212 ; freezing-point of, 242 ; grafting of, 



174, 176 ; influence of cold on, 232, 233 ; 



light on formation of tubers of, 93 ; 



- transitory cold on, 210 ; - tubers 

 of, on formation of flowers, 164. 



Potato-plants grown in light and darkness, 



86, Fig. 1 8. 

 Potonie, 161. 

 Pouchet, 230. 

 Prantl, 88, 91, 92, 95, 96, 118, 151, 168 ; on 



periodicity, 204. 

 Pressure, influence of, on cell-division, 42 ; 



- on freezing, 26, 244 ; on leaf- 

 primordia, 144. 



Preuss, 260. 



Prillieux, 58, 140, 239 ; on ice-formation in 

 Labiatae, 240. 



Primordia, influence of correlation on de- 

 velopment of, 162 ; light on de- 

 velopment of, 89 ; - - pressure on, 144; 

 modification of development of, 141 ; 

 position of, 143, 144; types of, 142, 



I43-. 



Pringsheim, 5, 156; on destructive action 



of light, 248. 



Projection lantern, use of, 19. 



Propionic acid, poisonous action of, 272. 



Prothalli, influence of starvation on, nS. 



Prothallium, induction of dorsiventrality in, 

 150, 151 ; influence of, on planes of 

 division of ovum, 158; regeneration of, 

 169. 



Protonema, formation of, in mosses, 167 ; 

 influence of light on, 91 ; resistance of, 

 to desiccation, 255. 



Protoplasm, extracellular, 178. 



Protoplasmic connexions, importance of, 

 178, 182-4. 



Protoplasts, fusion of, 177, 178; influence 

 of, on contiguous wall, 35. 



Prunet, 158. 



Prunus, elasticity of endodermis of, 55 ; 

 P. avium, early flowering of, 205 ; P. 

 triloba, shortening of resting period of, 

 209. 



Prussic acid, poisonous action of, 272. 



Pseudoparenchyma, 46. 



Pteris quadrmttrita, galls of, 171. 



Pterothamnion^ formation of branches in, 5. 



Pulst, on accommodation, 262 ; on non- 

 absorption of CuSO 4 , 266; on resis- 

 tance to poisons, 260, 262. 



Pulvini, influence of temperature on mo- 

 tilityof, 67; periodicity in, 200 ; strains 

 in, 62, 63, Fig. 16, 66. 



Putrefactive bacteria, temperature limits 



for growth of, 76. 

 Pyrus mains, growth of, as evergreen, 212. 



Ouercus, rapidity of growth in, 15; Q. pe- 

 duncnlata, growth of, as evergreen, 

 212, 213; periodicity in, 205. 



Rabinowitsch, 84, 227 ; on influence of 

 oxygen on cardinal temperatures, 80. 



Raciborski, 92, 116, 117, 130, 154, 162, 169 ; 

 on influence of inversion on growth, 

 no. 



Radius of curvature, influence of, on 

 stretching of wall, 59. 



Ranunculus Ficaria, causes of resting 

 period of, 212; changes in seeds of, 

 208 ; R. fluitans, causes of elonga- 

 tion of, 128 ; R. sceleratus, elongation 

 of petioles of, 122. 



Raphanus, 82, 168 ; R. sativus, correlation 

 of growth in, 89. 



Rapp, 131. 



Rauwenhoff, 86, 88, 102 ; on periodicity of 

 growth, 201. 



Ray, 88, no, 121, 129, 131, 194. 



Rechinger, 133, 158, 167, 209; on repro- 

 duction of horse-radish, 168. 



Regel, 241. 



Regeneration, 167. 



Reiche, 213, 217. 



Reinhardt, 5, 9, 17, 18, 32, 33, 34, ill, llS, 

 119, 257. 



Reinke, 5, 18, 20, 53, 55, 56, 96, 154, 164, 

 187; on influence of magnetism on 

 growth, 107; - sound-waves on 

 bacteria, 131 ; on periodicity, 204. 



Reproduction, 161, 167. 



Reproductive organs, influence of water on 

 formation of, 121 ; limits of tempera- 

 ture for production of, 80 ; sexual and 

 asexual, influence of oxygen-pressure 

 on formation of, 117. 



Resa, 207. 



Reserve-materials, influence of, on resis- 

 tance to desiccation, 253, 254. 



Resistance to extremes, 220, 224. 



Respiration, action of poisons on, 264. 



Resting periods, length of, 206 ; shortening 

 of, 209, 210. 



Retinispora, nature of, 152. 



Reuss, 13, 22, 66; on growth of lime 

 trunk, 1 8. 



Reversal experiments, 159. 



Reversion, 189, 190. 



Rheum, strains in stem of, 61. 



Rhizoids, influence of contact on formation 

 of, 130; gravity on formation 



of, 109 ; - light on development of, 



93. 94- 

 Rhizomes, regulation of depth of, 14. 



Rhythm in plants, 214. 

 Richardson, 249. 



