INDEX 



417 



Perennial herbs, in arctic coun- 

 tries 25. 

 Peridineae, constituents of 



phyto-plankton 157. 

 Pernettya empetrifolia, in Falk- 

 land Isles fell-field 260. 

 Persian salt-desert 334. 

 Peruvian loma, vegetation 287. 

 Pes-caprae-associatlon 227. 

 Petrophytes 240. 

 Phormium tenax, growing on 

 wet and dry soils 1 94. 



Photometric movements, of 

 leaves 19. 



Photophilous (heliophilous) 

 plants, characters 18. 



Phragmites communis 233; in 

 reed-swamp 187, 189; in sudd- 

 formation 189 ; travelling geo- 

 phyte Q. 



Phyllodoce caerulea 257. 



Phyllodoce-association, in 

 Finland 214. 



Physiognomic systems 4, 5. 



Physiognomy, factors influenc- 

 ing 25 ; of vegetation, circum- 

 stances determining 137. 



Physiological, dry ness, of soil 

 49, 5, 56, saline 223, wet 195 ; 

 races, of parasites 85. 



Phyto-plankton 155. See also 

 Plankton. 



Picea excelsa, as creeping shrub 

 215 ; as migrating species 364 ; 

 scrub-plant in Lapland 72 ; in 

 spruce-forest 313. 



Pigments, in alpine species 255. 

 See also Colours of flowers. 



Pinares, of Canary Isles, vege- 

 tation 315. 



Pine-forest (Pinetum) 312. 



Pines (Pineta) in woodland- 

 swamp 191. 



Pinetum, varieties 313 ; vege- 

 tation 312. 



Pinheiros, of Brazil 316. 



Pinus, in dune-forest 268; species 

 of, growing on both wet and dry 

 soils 194. 



P. canariensis 315. 



P. Ccmbra, as creeping shrub 

 216. 



P. halepensis 315. 



P. montana, in forest at high 

 altitudes 216; in Pyrenees and 

 French Alps 314. 



P. Pine a 315. 



P. sylvestris, in birch-forest 334; 

 as creeping shrub 215; in pine- 

 turn 312. 



P. Taeda, growing on wet and 

 dry soils 194. 



Piperaceae, as epiphytes 88. 



Pistacia, in Mediterranean flora 

 304. 



Placoditim mttrale, on shore 

 rocks 224. 



WARMING 



Plank-buttress roots, of trees 

 in tropical rain-forest 342. 



Plankton, 152, 154; adapta- 

 tions 157; composition 159; 

 distribution 157, 160; false 

 160 ; flora 155 ; flotation- 

 devices 158; foul-water 162; 

 neritic 160 ; oceanic 161 ; 

 power of flotation 157 ; quan- 

 tity 159 ; salt- water 160 ; 

 seasonal changes 159; sub- 

 formations 1 60; tycholimnetic 

 1 60 ; as ultimate source of food 

 159. See also Phyto-plankton. 



Plankton-formation 155. 



Plant-associations, see Asso- 

 ciations. 



Plant-communities 91 ; classi- 

 fication 131; definition 12, 13; 

 distribution, influenced by angle 

 of incidence of sun's rays 51, 

 influenced by direct sunlight 5 1 ; 

 dominant and sub-dominant 

 species 1 39 ; importance of soil 

 in determining 132 ; struggle 

 between 348, 358. See also 

 Communities. 



Plant-community, discussion 

 of term 91. 



Plant-form, influence of snow 

 72. 



Plant-geography, definition i ; 

 floristic, scope i ; oecological, 

 scope 2. 



Plant-physiognomy, in rela- 

 tion to landscape, significance 4. 



Plantago major, rosette-plant 



9- 



P. mantima 231. 

 Plants, and animals, relations 

 between 83. 



ain- 



forest 341.' 

 Platysma-heath, composition 



208. 



Pleuston, associations and dis- 

 tribution 1 66 ; adaptations 165 ; 



characters 164; flora 164. 

 Plocama pendula, in Canary 



Islands 279. 

 Plumbaginaceae, hydathodes 



103. 

 Pneumatophores, in mangroves 



1 86; in marsh-plants 186. 

 Poa, in meadow 323, 324, 325. 

 P. anceps, in tussock formation 



199. 

 P.flabellata, in tussock-formation 



200. 

 Pocket-leaves, of epiphytic 



ferns 89. 



Podostemaceae 167, 168, 169. 

 Pollen-mud 65. 

 Polycarpic plants, relations 7 ; 



groups 8. 



Wygonum equisetiforme 276. 



E e 



Platycerium alcicorne, pocket- 

 leaves 89 ; in tropica 



Polypodiumqttercifoliumjpockzt.- 

 leaves 89. 



Polytrichum 211, 212; in pro- 

 duction of sand-dunes 265. 



P. septentrionale 258. 



Polytrichum-kar 208. 



Pontie (Pannonian) hills, waste 

 herbage 290. 



Po-ophytes 135. 



Potamogeton crispus, hiberna- 

 cula 183. 



Potamo-plankton 161. 



Prairie, approximating to 

 meadow 325 ; associations 

 286 ; oecology 286 ; origin and 

 vegetation 285. 



Prairie-fires 353. 



Prairie-grass, association 286. 



Prairies 281. 



Primeval forest 339. 



Primula acaulis, flowers formed 

 under snow 252. 



Prop-roots, of mangrove-plants 

 236 ; otPandanus 342 ; of trees 

 in tropical rain-forest 342. 



Proteaceae, in Australian shrub- 

 steppe 281. 



Protection, of plants, against 

 animals 83. 



Psamma (Ammophila) arenaria 

 109; deep-growing roots 268; 

 importance as dune-grass 264 ; 

 in inland districts 263 ; in pro- 

 duction of high dunes 264. 



Psammeta 264. 



Psammogenous rocks 69. 



PsammophilouSjforest, tropical 

 littoral 272 ; halophytes 223, 

 262, zones 225. 



Psammophytes 136, 262 ; for- 

 mations 262 ; oecological fac- 

 tors 263. 



Pseudo-maqui 307. 



Psilophytes 136, 293. 



Psilotum flaccidum, in tropical 

 rain-forest 341. 



Psychrophytes 136, 248. 



Pteris aquilina, in evergreen 

 coniferous forest 311; in fern- 

 heath 292 ; in tjemoro-forest 

 of Java 300 ; travelling geo- 

 phyte 9. 



Pterocaulon vesumanum, on lava 

 241. 



Punas, of the Andes 253, 261. 



Pusztas, of Hungary 283, 284. 



Pygmy-trees, in tropical fell- 

 field 260. 



Pyrenees, Rhododendron-bush- 

 land on 2 1 5 ; Pinus montana on 

 216. 



Pyrola 311. 



Q. 



Quercus, in Mediterranean oak- 

 forest 308 ; in oak-forest 333. 

 Q. Ilex, in maqui 306. 

 Q. Suber, in Algeria 309. 



