INDEX 



381 



Periodicity— Continued 



length of day, 68 



of growth, 67-68 



seasonal dominance, 65 

 Persea borbonia, 257 



pubescens, 257 

 pH, 178-179 



and microorganisms, 179 



and plant responses, 179 



determination, 179 

 Phenology, 65 



Phoradendron flavescens, 191 

 Photometer, 129-131 



solarization, 131 



uses and limitations, 130-131 

 Photoperiodism 



abscission layers and leaf fall, 68, 

 143 



applied aspects, 141-143 



ecological significance, 143 



effect on Abelia, 142 



failure to become dormant, 143 



greenhouse uses, 143 



longday and shortday plants, 141 



necessary light intensity, 141 



seasonal phenomena, 141 



vegetative and reproductive activ- 

 ity, 141 

 Photosynthesis 



and temperature, 128 



relations to light, 134-135 



Vant Hoff's law, 128 

 Photosynthetic efficiency 



light, 129 



species differences, 129 

 Phytographs, 62, 63 



in climax studies, 231 



oak-hickory, 231 

 Phytometers, transpiration, 83 

 Phytosociology 



basic problems, 55 



development of, 55 



in successional studies, 233 



objectives, 55-74 

 Picea engehnanni, 145, 261 



glauca, 240, 241, 243, 261, 269, 303 



mariana, 216, 241, 303, 311 



rubens, 63, 244 



sitchensis, 279 

 Pifion-juniper climax, 267-268 

 Pinus albicaulis, 272 



aristata, 263, 264 



attejinata, 274 



balfouriana, 273 



banksiana, 241, 242, 248 



caribaea, 254 



contorta, 70, 262, 265, 271, 272, 

 274 



echi?iata, 252, 255 



flexilis, 145, 265, 273 



jeffreyi, 274, 276 



la??ibertiana, 272, 274 



latifolia, 266 



leiophylla, 266 



mo?iticola, 70, 271, 279 



muricata, 274 



murrayana, 194 

 mycorhiza, 194 



palustris, 253 



ponderosa, 265, 266, 268, 269, 272, 

 313 



var. arizonica, 266 

 var. scopulorwn, 265 



resinosa, 243, 251, 318, 319 



rigid a, 252 

 var. serotina, 257 



sabiniana, 275 



strobiformis, 264 



strobus, 243, 249, 250, 318, 319 



taeda, 24, 255, 319 

 in succession, 222 



virginiana, 252, 255 

 Pioneer plants, 219-220 



hydrarch succession, 216-217 



xerarch succession, 218 

 Pirola picta,. 272 

 Plants as factors 



competition, 188-190 



epiphytes, 193 



parasites, 190-192, 193 



soil flora, 197-198 



symbioses, 193-194 

 Plant geography 



descriptive, 234-299 



floristic, 15 



historical development, 15, 211- 

 212, 234 



of North America, 234-299 

 Plant indicators, 350-359 



agricultural, 352-355 



forest site, 357-359 



nature and use, 350-352 



range and pasture, 355-357 

 Plant nutrients, 179-182 



effect on distribution, 180 

 Plant sociology, 13, 55-74, 233 

 Plant succession, 211-233 

 Platanus occidentalism 255 

 Playas, 286 

 Pneumatophores, 176 



