INDEX 
dosperm nucleus, 40, 38*, 39%; 
tube, 42, 42*. 
Nut type of fruit, 80, 81*. 
Nux vomica, 283. 
Oak, family, 476; flowers, 476, 476*; 
plain sawed, 203*; quarter sawed, 
203*; uses, 476, 477*. 
Oat, flower, 20, 20*, 21*; kernel, 66; 
Smut, 393. 
Objections to Darwinism, 522. 
Oedogonium, 312, 312*. 
Oenothera, brevistylis, 530; gigas, 
530, 530*; laevifolia, 530; La- 
marckiana, 529, 529*. 
Oils, 273; fatty, 279; volatile, 281. 
Onion, section of root, 144*; section 
of bulb, 181*; seedling, 107, 105*. 
Onoclea sensibilis, 431, 431*. 
Ontogeny, 291. 
Odgonium, 312, 312*. 
Oéspore, 302. 
Open bundles, 195. 
Opening of buds, 205, 205*. 
Optimum temperature for germina- 
tion, 90. 
Orchid, family, 499; flowers, 26, 25*, 
499*. 
Order, in classification, 291. 
Organ, 6; essential organs of flowers, 
11; sex, 302. 
Organism, 6. 
Organic evolution, 513. 
Origin of Species, 517. 
Orthotropous ovule, 463. 
Oryzenin, 281. 
Oscillatoria, 298, 298*. 
Osmosis, 94; as related to cell activity, 
117; described, 116, 116*. 
Osmotic pressure, 119. 
Osmunda Claytonia, 431, 431*. 
Ovary, 33, 33*, 34*; inferior, 15, 15*; 
structure, 34, 34*, 35*, 36%; 
superior, 16, 15*. 
Ovules, 34, 34*, 35*, 36*; of Angio- 
sperms, 463; of Cycads, 448, 
448*, 449*; cellular structure, 39, 
39*; development to seeds, 43, 
579 
43*, 44*, 45*; of Pines, 454, 454*, 
455*; parts, 38, 38*; relation to 
seeds, 37. 
Ovulate strobilus, of Cycads, 446, 
447, 448*; of Pines, 453, 454*. 
Oxalic acid, 285. 
Ox-eye Daisy, 86. 
Oxygen, for germination, 92; in 
respiration, 121, 269. 
Palea, 17, 18*, 19*. 
Paleobotany, 3. 
Palisade tissue, 249, 250*. 
Palmaceae, 497. 
Palm family, 497. 
Pandorina, 304, 305*. 
Panicle, 23, 32; of Oats, 120*. 
Papain, 284. 
Papaw, 284. 
Pappus, 26, 24*. 
Parallel-veined leaves, 245, 244*. 
Paraphysis, 365, 366*. 
Parasite, 337. 
Parasitic roots, 163, 163*. 
Parenchyma cells, 127. 
Parsley family, 488. 
Parthenocarpic fruits, 50. 
Parthenogenesis, 355, 467. 
Parthenogenetic fruits, 50. 
Parthenocarpy, 467. 
Parts, of a flower, 11, 11*; of a leaf, 
234; of a pistil, 33; of a plant, 6. 
Pathogenic Bacteria, 346, 347*. 
Pea family, 484-486. 
Pea type of seedling, 109, 110*. 
Pear Blight, 348, 348*. 
Peat, 154. 
Peat Moss, 422. 
Pectic substances, 276. 
Pediastrum, 309, 308*. 
Pediastrum boryanum, 308*. 
Pedicels, 20, 20*. 
Pedigree culture, 560. 
Penicillium, 375; described, 376, 376*. 
Pepo type of fruit, 79, 78*. 
Pepsin, 94. a 
Peptases, 284. 
Peptones, 284. 
