430 



PLANT SOCIOLOGY 



Quercus pedunculata forest, 227 



pubescens, 183, 377 



robii,r forest, 47, 50 



sessiliflora, 351 



-Hypericum pulchrum assn., 352 



stellata, 268 



suber forest, 175 



velutina, 141, 217 

 Quotient, N. S., 143, 246, 258 



R 



Radiation, nocturnal, measurement of, 

 85 

 solar, 83, 84 

 ultra- violet, 106 

 Radiant energy, income of, 84 



heat and light, 97 

 Radioatmometer, 142 

 Radula, 268, 269 

 complanata, 16 

 Rafflesia, 290 



Rain climates, periodicity of, 113 

 forest, tropical, 367, 368 

 gauge, 114 

 Rainfall, distribution of, 112 

 duration of, 115 

 in western North America, 113 

 measurement of, 114 

 of Mediterranean basin, 115 

 winter, 112 



{See also Precipitation) 

 Rainproofing valves, for atmometers, 



139 

 Ramalina strepsilis, 292 

 Ramalinetum strepsilis, 241 

 Ranunculus, 292 

 hulbosus, 252 

 ficaria, 91 

 glacialis, 121, 310 

 nivalis meadow, 121 

 parnassifolius, 188 

 pygmaeus, 123 

 Raunkiaer's system of life forms, 288 

 Raw humus, 245, 250, 251 



acid reaction of, 251 

 Records of vegetation, procedure for 

 making, 68 



Red snow, 289 



soils of New Caledonia, 190 

 of southern Europe, 190 

 Region, definition of, 355 

 Regional units, 355, 366 

 Regions of vegetation, 345 

 Relative humidity, 132, 134 

 in forests, 133 



related to continental areas, 133 

 xerophytism, of habitat, 142 

 Relativity, law of, 180 

 Relict associations, on artificial habi- 

 tats, 353 

 communities, 352 

 and isolations, 352 

 Relicts, glacial, 218 

 significance of, 330 

 Tertiary, 187 

 Relief factors, 261 

 Rendzina soils, 163, 177, 312 

 Resistance of plants to cold, 131 

 Retama webbii, 153 

 Retrogression in garigue, 326 

 Retrogressive successions, 325 

 Rhacomitrium, 149 

 canescens, 309, 310 

 hypnoides, 38 

 lanuginosum, 307, 309 

 Rhamnus alaternus, 46 



pumila, 294 

 Rhizocarpon, 347 

 badioatrum, 38 

 polycarpum, 38 

 Rhizoctonia silvestris, 179 

 Rhizome geophytes, 301 

 Rhizophora, 193 

 Rhododendron, 89, 350 

 ferrugineum, 16 

 hirsutum, 16, 125, 188, 330 

 retusum, 203 

 Rhodomela subfusca, 346 

 Rhodoretalia, 371 

 Rhodoreto-Vaccinietum, 42 



-Vaccinion, 89, 124, 250, 364 

 Rhodoretum ferruginei, 323 

 Rhynchospora alba assn., 40, 344 

 Rhynchostegium rusciforme, 290 

 Rhytidium rugosum, 72 

 Ribes petraeum, 61 

 Riccia, 289, 290 



