INDEX 



441 



Omithogalum umbellatum, thermonastic 

 flower of, 113. 



Orobanche, nuclear movements of, 301. 



Ostillaria, 316, 383; movements of, 24, 

 270, 271, 272, 273, 274 ; -- in gelatine, 

 357 ; phototaxis of, 326. 



Osmotaxis, 178, 343, 344, 350, 351, 352; 

 detailed character of, 353, 354, 355 ; 

 nature of, 230. 



Osmotic energy, physical nature of, 400 ; 

 uses of, 402, 403. 



Osmotic pressure, influence of, on move- 

 ment, 73, 74 ; - - on pulsating vacuoles, 

 294, 296. 



Osmotropism, 178; nature of, 187, 230. 



Ostwald, 263, 368, 390, 394, 400. 



Otocysts, 224. 



Otoliths, 224. 



Ova, reunion of, 365. 



Overton, 180, 266, 323, 324. 



Oxalidaceae, sleeping flowers of, 103. 



Oxalis, 23, 26, 62, Fig. 20 ; action of in- 

 duction-shocks on, 360 ; continued ex- 

 citability of, 9, 70; dispersal of, 148; in- 

 fluence of strong light on leaflets of, 108 ; 

 latent period of, 68, 69 ; use of move- 

 ments of, 71 ; O.acetosella, influence of 

 feeble light on pulvini of, 142 ; of 

 induction-shocks on, 145 ; of stimuli 

 on rigidity of, 77 ; non-conduction of 

 stimuli in, 91 ; orientation of chloro- 

 plastids of, 329, Fig. 55, 330; sleep- 

 movements of, 102; thermonasty of, 

 113; variation movements of, 22; O. 

 dendroides, 91, 96; O. hedysaroides, 

 416; O. rosea, influence of light on 

 daily movements of, 108-11; photo- 

 nasty of, 122; thermonasty of, 113-15, 

 122 ; O. sensitiva, irritable cotyledons 

 of, So, 92. 



Oxygen, attractive action of, 180, 182 ; in- 

 fluence of absence of, on irritability, 140, 

 143, 144 ; -- on chemotaxis, 354, 355 ; 

 on heat-production, 371, Fig. 65, 372, 

 375) 377. 37 ; on irritable tone, 202 ; 

 - on luminosity, 383, 387 ; on 

 movement, 338 ; on production of 

 electricity, 395 ; on pulsating va- 

 cuoles, 299 ; on streaming, 314, 315, 

 339? 34 > n surface-tension, 283 ; 

 repellent action of, 351, 352; stimu- 

 lating action of, 347. 



Oxygenotaxis, 347. 



Oxygenotropism, 179. 



Oxytrichia, 310 ; galvanotaxis of, 361. 



Oxytropism, 179, 182. 



Paeonia officinalis, rise of temperature in, 



373- 

 Palm, 38 ; on circumnutation, 24 ; on mode 



of twining, 35 ; on origin of torsion, 41. 

 Palmellaceae, pulsating vacuoles of, 293, 



295. 



Palms, altered geotropism in roots of, 164. 

 Pandanus utilis, rise of temperature in, 



373- 

 Pandorina, ciliation of, 264 ; irritability of, 



226 ; locomotion of, 266 ; P. morum, 



421 ; influence of oxygen on movement 



of, 340. 

 Panicum, 218 ; P. miliaceum, heliotropism 



of, 193, Fig. 41 ; transference of stimuli 



in, 199. 

 Pantanelli, 13, 138; on sleep-movements of 



Porliera, 118. 

 Paoletti, 102, 144; on sleep-movements of 



Porliera, 118. 

 Papaver, curvature of peduncle of, 27, 164 ; 



P. somniferum, rise of temperature in, 



373- 

 Papilionaceae, opening of flower-buds of, 



23, 3"- 



Paraheliotropism, 106, 107, 108 ; defini- 

 tion of, 155. 



Parallelotropism, artificial production of, 

 162; definition of, 155, 156 ; origin of, 

 1 60. 



Paramaecium, chemo- and osmotaxis of, 

 353. 355; lifting-power of, 268; pul- 

 sating vacuoles of, 296 ; reversal of 

 movements in, 266 ; thermotaxis of, 

 317; P. aurelia, galvanotaxis of, 361, 

 362, 363 ; pulsating vacuoles of, 295 ; 

 P. bursaria, galvanotaxis of, 361. 



Paranasty, definition of, 3 ; in apices of 

 twiners, 37. 



Parietaria, movements of stamens of, 146, 

 147. 



Parnassia, movements of stamens of, 24. 



Passerini, 372, 379. 



Passiflora, 42 ; absence of pits in tendrils 

 of, 65 ; P.gracilts, circumnutation of, 21. 



Pasteur, 378. 



Pauli, 282. 



Payer, 176. 



Pea, influence of temperature on circumnu- 

 tation of, 29. 



Pearl, 362. 



Peduncles, geotropism of, 164, 165 ; helio- 

 tropism of, 174. 



Peirce, 48 ; influence of gravity on contact- 

 irritability, 28. 



Pelltonia, 253. 



Pelomyxa^ locomotion of, 281 ; P. palu- 

 stris, influence of oxygen on, 340 ; - 

 of hydrogen on, 341 ; photophobism of, 

 308, 320. 



Peltigera, changes of irritability in, 162. 



Penicillium, growth-movements of, 19 ; in- 

 difference of, to contact, 83 ; influence 

 of alkaloids on, 342 ; P. glaucum, 

 chemotropism of, 181, Fig. 38. 



Penium, phototaxis of, 325. 



Peptone, chemotactic action of, 354, 

 chemotropic, 181 ; influence of, on 

 luminosity, 386. 



