ACKNOWLEDGMENT 



Since the initial appearance of this work in preliminary mimeo- 

 graphed form in 1936, a great many people have contributed original 

 information and suggestions without which the present publication 

 would be much less complete. To all of these people, the author 

 wishes to express his sincere thanks. 



He is particularly indebted to Ernest G. Holt for his advice, sug- 

 gestions, and criticism, as well as his very considerable assistance dur- 

 ing the preparation of the manuscript ; to T. H. Kearney, for permis- 

 sion to use his manuscript on the flora of Arizona ; to V. L. Cory and 

 H. B. Parks for the use of their manuscript catalog of the Texas 

 flora, and Mr. Parks' manuscript on the useful properties of Texas 

 plants; to F. L. Mulford for the plant-growth region map, together 

 with his chapter on its development; to C. W. Thornthwaite for the 

 map of the climatic regions; to Clarence Cottam and his assistants, 

 Phoebe Knappen, F. M. Uhler, Neil Hotchkiss, and A. L. Nelson, 

 for their very great help in making available considerable data from 

 the Section of Food Habits Kesearch of the Bureau of Biological 

 Survey; to E. P. Killip for advice on the taxonomic problems; to 

 E. L. Crandall for his help with some of the photographs and to C. R. 

 Ball, who assisted materially in the preparation of the section on 

 Salix. 



Suggestions and criticisms concerning the botanical material have 

 been offered by E. J. Alexander, M. L. Fernald, E. J. Palmer, H. M. 

 Raup, H. A. Gleason, W. H. Camp, H. E. McMinn, F. J. Crider, 

 C. V. Morton, M. Van Rensselaer, E. H. Graham, Mildred Mathias, 

 H. L. Shantz, E. V. Komarek, Hilda Cunniff, Fred Gibson, and his 

 assistant, J. Whitehead, H. S. Yates, M. G. Netting, P. B. Sears, 

 H. L. Whitaker, C. F. Swingle, and Russell Albright. 



Suggestions and criticisms concerning the wildlife material were 

 received from W. L. McAtee, H. L. Stoddard, Aldo Leopold, D. M. 

 Gorsuch, F. N. Hamerstrom, Jr., C. B. Terrell, R. T. King, Gardiner 

 Bump, R. O. Stevens, A. M. Pearson, Logan Bennett, P. D. Dalke, 

 V. E. Davison, N. W. Hosley, W. E. C. Todd, R. E. Yeatter, and 

 H. D. Ruhl. 



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