GENEEAL rNDEX 



323 



Oils, 5 ; antiseptic, 136 ; fixed, 142 ; 



as a food-reserve, 146, in seeds, 



147 ; volatile, 143, 151 ; in xero- 



phytes, 42 

 Oily seeds, 148 

 Old man's-beard, 217. See Clematis 



Vitalba 

 Olive, 23 

 Onion : bulb, 150 ; bulbils, 160 ; infl., 



181 ; seeds, *146 ; sugar, 146, 150 

 Ononis arvnsis, spines, 44 

 Open associations, 277 ; Iiabitats, 16 

 Opium, 143, 152 

 Orange, 23 

 Orchid : bird's-nest (see Neottia) ; 



coral-root (see Gorallorhiza) ; fr., 



189; honey, 173; infl., 180; 



pollination, 177 ; seed, 195 ; 



tubers. 111 

 Origin ol species, 202 

 Orobanche, 127 

 Orobua, fr., *189 

 Osier-beds, 244 

 Osmosis, 25, 91 

 Ovary, 162, 183 

 Ovnie, 162 

 Oxalis, 62 ; aril, 196 ; cleistogamous 



fls., 165 ; fr., 189 ; oxalic acid in, 



143 ; rhizome, 154 ; seeds, 196 ; 



sleep-movements of leaves, 70, 



•71. See Sorrel 

 Oxtongue, 60, 217. See Hdminthia 



echioides 

 Oxygen, 6, 7 ; in air, 78, 79 j in 



water, 48, 50 ; in soil, 88 



P«Bony, 168 



Palisade-tissue, 41, *72 



Palm, 23 ; -oU, 148 



Pampas, 20 



Panicle, 178, 179 



Pa/paver somnijeram, alkaloid of, 



143, 152 

 Paper-making materials, 152 

 Pappus, 195 

 Parasites, 6, tl25, 206 ; partial, 126 ; 



total, 126 ; hemi-parasites of 



meadow-land, 263, of natural 



pasture, 257 

 Parallel development, IDS 

 Parietaria o/jlciTialis, fls., 177 

 Paris guadrifolia, 214 

 Park-land, 17, 126 

 Parsley, 181 

 Parsnip, 150 

 Partial parasites, 126 ; saprophytes, 



125 



Passion-flower, tendrils, *118 

 Pastures, 15, 18, 20; alpine, 230, 

 251, 259 ; artificial, 20, 261, weeds 

 of, 264; limestone-, 230, 259; 

 lowland-, 230, 258 ; natural, 257 ; 

 sub-alpine, 230, 258 



Pea : fr., 188 ; pollination, 165 ; 

 protein of, 147 ; root-nodules, 95 ; 

 seeds, 146, 195; tendrils, 118. 

 See Lathyrus 



Peach : fr., *192 ; origin of, 205 



Pear : bud-scales, 61 ; cultivation of, 

 149 



Peat, 17, 83, 93, 94, 244, 248, 254 ; 

 absorptive power of, 87 ; -bogs, 

 246, 248, xerophytio factors of, 

 35 ; moorland-, constitution of, 

 249, comparison with marsh-peat, 

 249, conditions necessary for 

 formation of, 248 ; water-capacity 

 of, 87. See Humus 



PediciUaris, 59 ; parasitic nature, 

 126 



Pdargmium : fr., 190, 195 ; infl., 181 



Pellitory. See Parietaria officinalis 



Penny cress, 216 



Pepper, 151 ; -mint, 151 



Percolation in soils, 87 



Perennating organs, 62, 109 ; struc- 

 tures, t62 



Perennials, 108 ; evergreen, 109 ; 

 herbaceous, 109, 115, 145 ; tropo- 

 phytic, 59 ; xerophytio, 59 



Perianth, tl62 



Pericarp, 183 



Permeability of soils, 87 



Peruvian bark. See Cinchona 



Petals, 162 



Petioles : oi Acacia, 43, *44 ; of float- 

 ing aquatic leaves, 51 



Phaseolus vulgaris, twiner, 116. See 

 Scarlet ixmner. 



PMeum arenarium, 60 



Phloem, *45 ; in aquatics, 49 



Phormium tenax, 42 



Photosynthesis, t4, 66, 78 



Phragmites, 62 ; -associations, 242, 

 245 



Phylloclade, 44, *45 



Phyllode, 43, *44, 46 



Physical action of water on rooks, 

 81 ; properties of soil, 85 



Physiognomic groups, 16 



Physiological dryness, 34, 8S^ 



Physiology, tl03 



Pillwort Sea Pilvlaria 



PUularia. 28. 50 



