CONTENTS. 



VII 



FAOE. 



VI. Stabilization and Climax — Cont. 

 V The Climax. 



Concept 105 



Nature 106 



Kelation to succession 106 



Kinds of climaxes .' 107 



SubcUmaxes 107 



Potential climaxes 108 



Changes of climate 109 



Preclimax and postcUmax 109 



Changes of climax 110 



VII. Structure and Units of Vegetation. 

 Deedopment and Structure. 



Relation Ill 



Kinds of structure Ill 



Zonation Ill 



Relations of climax zones 113 



Significance of alternation 115 



Developmental relation of layers 115 



Relation of seasonal aspects 116 



The Units of Vegetation. 



Historical Summary : 



The formation concept 116 



Grisebach's concept of the formation .... 116 



Drude's concept 117 



Clements's concept 118 



Moss's concept 118 



Schroter's concept 119 



Gradmann's concept 119 



Warming's concept 120 



Negri's concept 122 



Correlation of divergent views 122 



Significance of development 123 



Earlier suggestions of developmental view 123 



The Formation: 



Developmental concept of the formation . 124 



Analysis of the formation 125 



Formation units 125 



Formation 126 



Names of formations 127 



Climax Units: 



Association 128 



Consociation 129 



Society 130 



Bases 131 



Kinds of societies 132 



Aspect societies 132 



Layer societies 133 



Cryptogamic societies 133 



Terminology 133 



Changes of rank or dominance 134 



Clan 134 



Serai Units: 



Nature and significance 135 



Associes 136 



Consocies 137 



Socies 138 



Colony 138 



Family 139 



Summary of units 139 



Mixed communities 139 



Nomenclature of units 140 



Formation groups 142 



Bases 143 



Developmental groups 143 



PAGE. 



VIII. Direction or Development. 



Development always progressive 145 



Nature of regression 145 



Course of development 146 



Regression and retrogression 146 



Nilsson's view 146 



Cowles's view 147 



Cajander's view 149 



Sernander's view 149 



Moss's view 150 



Hole's view 154 



Conversion of forest 155 



Status of forest in Britain 156 



Artificial conversion 157 



Graebner's studies: Conversion of forest to 



heath 157 



Conversion of forest into moor 159 



Causes of conversion 161 



Possibility of backward development 162 



Degeneration 163 



Regeneration 163 



Correlation of progressive developments 164 



Convergence 165 



Normal movement 166 



Divergence 167 



IX. Classification of Seees. 



Historical 168 



Clements's system 168 



Normal and anomalous succession 169 



Primary and secondary succession 169 



Cowles's system 171 



Possible bases of classification 175 



Developmental basis of classification 175 



Initial areas and causes 176 



Relative importance of bases 177 



The climax as a basis 177 



Recognition of climax areas 177 



Climaxes of North American vegetation 179 



Subclimaxes 180 



Relationship of climaxes 180 



Names of cUmaxes 181 



Priseres and subseres 1^2 



Hydroseres and xeroseres 182 



Phylogenetic system 183 



X. Climax Fobmationb of North America. 



Classification 184 



The Dedduoua Forest Climax. 



Prisere 184 



Hydrosere 184 



Xerosere 203 



Subsere 212 



The Prairie-Plains Climax. 



Prisere 214 



Xerosere 214 



Hydrosere 220 



Subsere 221 



The Cordilleran Climaxes. 



Priseres 225 



Subseres 226 



