288 



INDEX 



influence of external conditions on re- 

 production of, 198 ; intercalary growth 

 in, 10 ; nuclear fragmentation in, 41 ; 

 ultra-maximal temperature for, 231 ; 

 O. diplandnim, influence of light on 

 reproduction of, 91. 



Ohlert, 7. 



Oil, influence of, on resistance to cold, 247. 



Olin, 253. 



Oltmanns, 78, 83, 84, 85, 119, 209 ; on con- 

 tinuance of growth in electric light, 94. 



Ono, I II. 



Onoclea struthiopteris, sporophyll formation 

 in, 164. 



Onygena equina, condition for germination 



of, 113. 



Oppenheim, 270. 

 Opuntid) influence of darkness on, 87 ; O. 



Fiats indica, influence of gravity on, 



109. 



Orchids, influence of boring larvae on for- 

 mation of ovules in, 173. 

 Organic acids, importance of, in leaf-fall, 



218. 

 Orobanche, condition for germination of, 



114; development of ovule from sus- 



pensor of, 142, 168. 

 Orthogonal trajectories, 47, 48. 

 Orthostichies, 47. 

 Orthotrichum ajfine, resistance of, to heat, 



229. 



Ortmann, 190. 

 Oscillarm, embryonic character of, 4 ; 



growth of, at high temperatures, 77 ; 



resistance of, to desiccation, 250, 255 ; 



ultra-maximal temperature for, 231. 

 Osmotic agencies, injurious action of, 256. 



concentration, influence of, on freezing- 



point, 241, 243. 



pressure, calculation of, from stretching 



of cell-wall, 59 ; influence of enforced 

 cessation of growth on, 124; on 

 growth, 26, 27 ; - on growth con- 

 tractions, 15 ; on segmentation of 

 ovum, 147. 



Ostwald, 26, 37, 243, 244, 272. 



Ott, 55. 



Otto, 123, 263. 



Overton, 260, 265, 266, 268 ; on progressive 

 action, 271. 



Oxalis, influence of desiccation on seeds of, 

 254 ; strains in curving pulvini of, 58 ; 

 O. elegans, contraction of roots of, 14. 



Oxygen, influence of absorption of, on resis- 

 tance to heat, 228 ; - on action of 

 light, 248, 249 ; -- on growth, 114. 



Oxygen-pressure, action of, 269. 



Palisa, 167. 



Palisade parenchyma, influence of light on 



formation of, 87, Fig. 19, 88. 

 Palladin, on influence of transpiration on 



etiolation, 100. 



Pandanus, growth of cell-walls of, 30. 



Pangens, 186, 187. 



Paraboloids of revolution, 48. 



Paranasty, definition of, 73. 



Paratonic, definition of, 75. 



Parietaria arborea, resistance of, to desic- 

 cation, 250. 



Parnassia palustris, early flowering of, 211. 



Parthenogenesis, 147. 



Pasteur, 229, 252 ; on influence of medium 

 on resistance to heat, 228 ; on resis- 

 tance of bacteria to heat, 227. 

 - and Joubert, 227. 



Pear, freezing-point of, 242. 



Pedersen, 81, 84; on cardinal temperatures 

 for growth, 76. 



Pedtastrum, coenobium of, 177. 



Peirce, 171, 178. 



Pelargonium, grafting of, 176. 



Pellia epiphylla, elongation of sporogonial 

 stalk in, 10. 



Pellionia Daveauana, chloroplastids of, 36. 



Pelomyxa palustris, action of hydrogen on, 

 261. 



Pelvetia canaliculata, polarity of, 157. 



Penicillium, influence of air on reproduc- 

 tion of, 198 ; - cold on, 238 ; 

 moisture on formation of spores by, 

 123; resistance of, to poisons, 260-2; 

 P. glaucitm, accommodation of, to 

 poisons, 262, 263 ; action of CuSO 4 

 on, 261 ; -- of ZnSO4, 262 ; heat-rigor 

 in, 225 ; influence of food on cardinal 

 points for, 80 ; non-absorption of 

 CuSO 4 by, 266 ; non-germination of, 

 on water, 113; temperature limits for 

 growth of, 76. 



Peptone, influence of, on germination, 113; 



on nitrifying bacteria, 112. 

 Perennating organs, causes inducing for- 

 mation of, 72. 



Perennation, 205. 



Periclinals, 48. 



Pericyclic sclerenchyma, value of, 54. 



Periodicity, heredity of, 195, 213, 214; in- 

 fluence of external conditions on, 209 ; 

 - food on, 215; internal factors in, 

 214; of growth, 197; - daily, 200; 



yearly, 204 ; origin of, 212. 

 Perithecia, limits of temperature for forma- 

 tion of, 80. 



Peters, 133, 208. 



Petersen, 207. 



Pethybridge, 118. 



Petiole, influence of grafting on, 176. 



Pettersen, 119, 258. 



Petunia, development of flower of, in dark- 

 ness, 91. 



Peyritsch, 171. 



Pfeffer, 9, 12, 16, 19, 21-5, 28, 29, 31-4 

 (growth), 41-3 (cell-division), 50, 55-60 

 (elasticity and cohesion), 62-4 (tissue- 

 strains), 73, 83, 92, 93, 101, 109, 1 10, 119 



