INDEX 



459 



(Edogonium, 20, 21. 



Oils, 177. 



Onion, 377. 



Oogonium, 27. 



Oospore, 23. 



Orange, 394. 



Orchard fruits, 389. 



Orchards, 389. 



Orchid, flower of, 161 ; pollina- 

 tion of, 161. 



Organic, 32. 



Oscillatoria, 13, 14. 



Osmosis, 264. 



Ovary, 138. 



Ovule, of Gymnosperms, 120, 

 122 ; of Angiosperms, 140. 



Oxygen, 300; as a by-product, 

 36. 



Palisade cells, 194, 206. 

 Palmate, 189. 

 Pansy, 405, 406. 

 Parallel-veined, 189. 

 Parasite, 40. 

 Parsnip, 376. 

 Peach, 148, 389, 392. 

 Peach leaf curl, 445. 

 Pear, 388, 391. 

 Pear blight, 435. 

 Peas, 386. 



Pedigree culture, 335. 

 Peony, 131. 

 Perennials, 238. 

 Perianth, 130, 131. 

 Perigynous, 156. 

 Petal, 132. 

 Petiole, 187. 

 PhaeophycesB, 31. 

 Phloem, 237. 

 Phlox, 133. 

 Phosphorus, 304. 

 Photosynthesis, 34, 195. 

 Phototropism, 183. 

 Phycomycetes, 57. 

 Physics of soil, 309. 



Pine, 227. 



Pineapple, 149. 



Pine needles, 21^; section of, 



215. 



Pinnate, 189. 

 Pistil, 139. 



Pitcher-plants, 218, 219. 

 Pith, 236. 

 Pith rays, 237. 

 Plains, 283. 



Plant associations, 272. 

 yiant-breeding, 5, 164, 333. 

 Plant succession, 276. 

 Plastid, 33. 

 Pleurococcus, 12. 

 Plum, 393 ; black knot on, 446. 

 Plume, 126; escape, 181. 

 Pods, of iris, 147 ; of sweet pea, 



146. 



Pollen, 121. 

 Pollen sac, 135. 

 PoUen tube, 125. 

 Pollination, 125 ; by insects, 



158. 



Polypetalpus, 133. 

 PoreUa, 72. 

 Potato, 369, 370, 371; disease 



of, 440, 441 ; tuber, 328. 

 Potentilla, 230; flower of, 156. 

 Prairies, 284. 

 Profile leaves, 211. 

 Prop-roots, 265, 266, 267. 

 Protective positions, 210. 

 Protective structures, 204. 

 Protein, 37. 

 Protoplasm, 9. 

 Protoplast, 9. 

 Pteridophytes, 7, 88, 114. 

 Pumpkin, 385. 



R 



Radish, 254, 372, 374. 

 Rain, protection against, 209. 

 Raspberry, 391, 399. 

 Reaction, 185. 

 Receptacle, 152. 



