VIII CONTENTS. 



Part III. The Correlation of Distributional Features with Climatic 



Conditions. 



PAGE. 



Introduction 389 



Presentation of the Correlation Data. 



I. Methods of correlation 393 



II. Climatic extremes for each of the various vegetational features 398 



Discussion and Preliminary Interpretations op the Correlation Data. 



1. Correlations as indicating controlling conditions 487 



II. Comparative climatic features of the nine general vegetational areas. . . . 490 



III. Conditions that probably determine the general vegetational areas. 



1. Observations from the charts 498 



2. Discussion of the observations 515 



IV. Conditions that probably determine the life-zones of Merriam. 



1. Observations from the charts 519 



2. Discussion of the observations 526 



V. Conditions that probably determine the distribution of growth-forms and 



the ecological distribution of individual species. 



1. Growth-forms 529 



2. Species 537 



VI. Correlation of vegetational areas with generalized climatic provinces. 



1. Introductory 570 



2. Temperature provinces 571 



3. Moisture provinces 572 



4. Temperature-moisture provinces based on product index 576 



5. Two-dimensional climatic provinces 578 



Conclusion ^^^ 



Literature References 587 



