iyj>KX 



Njtrf'.issus, "^tomata of, 196, 

 Xasturtium. leaf-stalk of, ;i''t>; as tendril, 

 270. 



polJeii of, 293. 

 Natural selection, 330. 331. 442-453. 

 Xectar attriicts insects, 3D0 



protection of, 29't. 

 Nectarine, origin of, 420. 

 Needs of plant, 326. 

 Nepenthes, 172. 

 Nerium. See Oleander. 

 Nettle, pollen of, carried by wind, 300. 



protection of, against animals. 2J1. 

 Nf Arman, on bacteria. 408. 

 Nieotiana. See Tobar-fo. 

 Nightshade family, fross-pollination of, 303. 

 Nitragin, 385. 



Nitrates, produced by bacteria, 383-385. 

 Nitrate of potassium. See Potassium 



nitrate. 

 Nitrate of silver. See Silver nitrate. 

 Nitrate of soda. See Sodium nitrate. 

 Nitric acid. See Acid, Nitric 

 Nitrites produced by bacteria. 383-3h.">. 

 Nitrogen combines with starch to form 

 proteids, 253. 



conserved by plants, 176. 



effect of, on plant, 349, 350. 



escapes from soil, 148, 149. 



how supplied to soil. 147, lAh, 149,* l.'tt.i 



in air, 149, 383-385. 



~ beans, 177. 



— eggs, 177. 



— peas, 177. 



— percolating water, 149. 

 needed by animals, 176. 

 plants, 139. 140,* 176. 



prepared for plant by bacteria, 149,* 150, 

 383-385. 



prepared for plant by fungi, I.'>0. 



produced by bacteria, rjg;:. 



promotes leaf-, rather than fruit-produc- 

 tion, 318. 



selected by plant, 161. 



taken from air by bacteria, 383-r;s.'. 



some plants, 149. 



test for, in soils. 15.'). 



waste of. by animals, 176. 

 Node, 327. 



Node, growth at, 249, 250. 



Notching, to increase fruit production, j1>. 



Nucleus, 6.'.,* 66, 290, 291,* 311. 



Nuphar. See Spatterdock. 



Nutrition. See Food. 



Nuts, absorption of water by, 7. 23,* 29. 



protection of, against drying, 317. 



seed of, 320. 



Nymphsea. See Lily, Water. 



Oak, cambium of, 232,* 246. 



fibrous bundle of, 226. 



food convej'ed to fruit of, 3L3. 

 I latent buds of, 262. 



path of water in, 226, 230, 232,* 233, 2:^.* 

 ! 235. 



pollen of, carried by wind, .300. 



starch in, 259. 

 I stem of, microscopic structure of, 232.=^ 



233, 2.34.* 2;!.'. 246. 

 i wood of, compared with wood of Pine, 

 I 235, 238. 



I Oat contains no pepsin, 172. 

 i germination of, 47. 



stomata of, 196. 



ovary of. 290.* 



pollen of. 290.* 



stigma of. 290.* 



style of, 290.* 

 ] Oat. Wild, seeds of, bury themselves, 71, 

 j Oat Rust. 404, 405. 

 Oat-smut, 400-401. 

 i Odor attracts insects, 299, 300. 

 { (Enothera. See Primrose, Evening, 

 I Oil, emulsification of, 169, 170. 

 ; energy from. 173. 



formation of, 2(^11. 



in eggs, 177, 



— fruits, 314, 



— growing region, 253. 



— seeds, 165. 177, 437. 

 injures leaf, 215. 

 produced from starch, 314. 

 saponification of, 170, 171, 

 test for, 165. 2.59. 



See, also, Fat. 

 OU, Cocoanut, 169, 170, 

 Oil, Com, 437. 

 Oil, Cottonseed, 147, 169, 170. 



