Southeastern Washington and Adjacent Idaho. 3 
offered the ecologist in southeastern Washington. It is a field in 
which many stages in succession are offered within relatively easy 
reach of a base station and one in which the vegetation so clearly 
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, II). 
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: 
3 
