374 



THE STUDY OF PLANT COMMUNITIES 



Climatic factors— Continued 

 insolation, 116-118 

 precipitation, 88-97 

 radiant energy, 116-143 

 temperature, 118-128 

 Climax 



an indicator of climate, 224 

 basic concept, 226 

 characteristics, 223-224 

 monoclimax interpretation, 226-229 

 polyclimax interpretation, 226-229 

 present distribution of, 234-235- 



299 

 relation to climate, 223-224 

 relationships of successional trends, 



223-224 

 stability, 224 

 types, 226-229 



uniformity and variations, 224-226 

 variations related to time, 224 

 Climax communities 

 present distribution, 236-299 

 shifts with time, 301-314 

 Climax, distribution of, 234, 235-299 



controlling factors, 234 

 Climax formations of North America 

 listed, 237 

 map, 235 

 Climax regions, 225 

 formations listed, 225 

 uniformity of life form, 224-225 

 Climax regions of North America 



by formations, 236-299 

 Climax, study of 



criteria for recognition, 230 

 procedure in local study, 230-233 

 sampling, 232-233 

 use of quantitative data, 231-232- 

 233 

 Climax, types of 

 disclimax, 227 

 edaphic, 226 

 physiographic, 226 

 postclimax and preclimax, 227-229 

 subclimax, 226 

 Climaxes of past, reconstruction, 301- 

 314 

 dendrochronology, 308-310 

 paleo-ecology, 301-304 

 pollen analysis, 304-307 

 relict method, 310-314 

 Climographs, 98 

 Clintonia borealis, 241 



Clouds 

 causes, 87-88 

 classification, 88 

 effect on temperature, 125 

 source of precipitation, 88 

 Coefficient of community, 74 

 Cold air drainage, 98, 124 

 Cold front (air masses), 87 

 Coleogyne ramosissima, 286 

 Colloids 

 and exchangeable bases, 180 

 and soil characteristics, 153 

 and soil water, 162 

 Colluvial soils, 150 



talus, 151 

 Community 

 abstract, 21, 69-74 

 analysis a necessity, 34 

 basic vegetational unit, 21 

 classification by life form, 20 

 concrete, 21 

 definition, 21 

 description justified, 33 

 first recognized as basis of study, 



16 

 fixing the concept of, 33-34 

 illustrated, 18, 19 

 its nature, 21 

 recognition, 21 

 size, 21 



synthetic analysis, 69-74 

 Communities (layer or strata) 

 of the forest floor, 23, 24 

 synusia, 25 

 Community disturbance 



drainage, fire, irrigation, 203 

 Community dynamics, 211-314 

 methods of study, 229-233 

 plant succession, 211-233 

 present distribution of climaxes, 



234-299 

 shifts of climaxes with time, 300- 

 314 

 Community structure 

 Quantitative characters, 56-63 

 cover and space, 61 

 density, 57 

 frequency, 57 

 numbers of individuals, 56 

 Qualitative characters, 64-69 

 dispersion, 64 

 periodicity, 65 

 sociabilitv, 64 

 stratification, 65 



