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Southeastern Washington and Adjacent Idaho. 3 



offered the ecologist in southeastern Washington. It is a field in ^Al 1 

 which many stages in succession are offered within relatively easy i 



reach of a base station and one in which the vegetation so clearly \A| ^r 

 reveals adjustment to climatic and edaphic conditions that one 

 could scarcely wish for a better place in which to measure the 

 factors of the habitat and the vegetational responses. Moreover, 

 in this great inland province, practically no botanical work except 

 of a taxonomic character has been done (3, 9, 10, n). 



Because of the high fertility of the deep basaltic soils, the 

 prairie region has largely been broken up for the growing of 

 wheat. Indeed, only isolated tracts of the best developed prairies 

 remain intact, while hundreds of acres of the drier bunch-grass 

 lands have been broken up during the time of the progress of 

 this work. It seemed unfortunate that a record of the rapidly 

 disappearing vegetation of this interesting region had not been 

 made. Accordingly, early in the spring of 1912, reconnaissance 

 work was begun, with Pullman, Washington, as the base station. 



Ecological work was pursued vigorously in season and out 

 (with the exception of the summer of 1912) until the fall of 1914. 



In the course of this investigation I have become indebted to 

 several persons to whom I wish to express my appreciation for 

 their services. I am pleased to express my appreciation first of 

 all to Dr. F. E. Clements, of the University of Minnesota, who 

 visited my field briefly in 1914, for many valuable criticisms and 

 suggestions. Dr. Raymond J. Pool, of the University of Ne- 

 braska, has read the first draft of this paper and I am grateful 

 to him for kindly suggestions. Thanks are due to Dr. T. C. 

 Frye, of the University of Washington, for the identification of a 

 number of mosses, and to the late Dr. H. E. Hasse of Santa Mon- 

 ica, California, who was kind enough to identify all of my lichens. 

 Wilting coefficient determinations of soils were made under the 

 direction of Dr. L. J. Briggs, of the United States Department 

 of Agriculture, to whom I wish to express my appreciation. The 

 chemical and physical analyses of soils were made by the depart- 

 ments of chemistry and soils respectively, of the Washington 

 Agricultural Experiment Station at Pullman. I wish further to 

 acknowledge my indebtedness to Mr. Walter L. Muenscher and] 



