406 
Nucleus, 178. 
Nucleus of root-hair, *49. 
Nut, #222, 223. 
Nutrient substances, 168, 169, 171. 
Nutrition of plants, 165-176. 
Oak leaves, arrangement of, *140. 
Oat, root-system of, 48. 
Obovate, *131. 
Obtuse, *151. 
Odors of flowers, 357. 
Offensive-smelling plants, 352. 
Oil, 21, 22. 
Oil, essential, 24. 
Oil, extraction, 22. 
Oil, testing seeds for, 21, 22. 
Onion, bulb of, 77. 
Onion leaf, section of, *79. 
Onion, structure of, 116. 
Onion, tests for food-materials in, 
116, 117. 
Odégonia, *251. 
Odsphere, *249, *251, 280, *284, 
285. 
Odspore, 247, 249. 
Opposite, *65, *140, *141, *142. 
Orbicular, *131. 
Orchid, aerial roots of an, *37. 
Order, 230. 
Organs, essential, *197. 
Organs, vegetative, 50. 
Oscillatoria, study of, 239, 240. 
Osmosis, 50-54. 
Osmosis in an egg, 50, *51. 
Osmosis in root-hairs, 53, 54. 
Ovary, 201, 202, *203, *205. 
Ovate, *131. 
Ovoid, egg-shaped. 
Ovule, 202, *203. 
Ovule, spruce, fertilized, #303. 
Ovule, structure of, *215. 
Bei ai 
FOUNDATIONS OF BOTANY 
Oxalis leaf, development of, *127. 
Oxidation, 11, 12. 
Oxygen, 11, 12, 166, 167, 168. 
Oxygen-making, 167, 168. 
Palisade-cells, *151. 
Palmate, *133. 
Pampas region, 393. 
Panicle, *189, 190. 
Panicum, *381. 
Pansy, leaf-like stipules of, *135. 
Papilionaceous corolla, *199. 
Papille on stigma of a lily, *214. 
Paraphyses, 251, *252. 
Parasites, 39, 336-338. 
Parasitic roots, 39, *40. 
Parenchyma, 94. 
Parietal placenta, 203, *205. 
Parsnip root, study of, 45, 46. 
Pea seed, 8. 
Pea seedling, mutilated, 14. 
Pea seedling on clinostat, 58. 
Peat bogs, 327. 
Peat moss, *327. 
Pedicel, *186, 187. 
Peduncle, *186, 187. 
Peg of squash seedling, 27. 
Pepo, 224. 
Perennial, 47, 71. 
Perfect, 198. 
Perianth, *197. 
Pericarp, 224. 
Perigynous, 204, *205. 
Perithecia, 263. 
Permanganate test, 28. 
Petal, 197. 
Petiole, 130, 134. 
Pheophycee, 232. 
Phanerogams, 231, 233. 
Phanerogams, classes of, 233. 
Phosphorus, 165. 
