F OREW ORD 
The study, of which this paper is the record, was begun in 
the summer of 1925 when I was in the employ of the office of Blister 
Rust Control, Bureau of Plant Industry. Because of the need for a 
manual on the part of the several government agencies then operating 
in northern Idaho, I was encouraged by officials of that office, not- 
ably Samu@l B. Detwiler and Stephan Wyckoff, who, with officials of 
the Forest Service, offered all available facilities for its pursuit. 
The descriptions of a majority of the species were prepared in the 
field and later amplified in the herbarium or, if prepared from her- 
barium material, notably while in residence at Kew, and at the 
Missouri Botanical Garden, were later checked in the field. Excep- 
tions are the grasses, sedges, and willows, where the descriptions 
rest in the main upon herbarium specimens. The work was continued 
for several summers until 1927, and in 1929. the manuscript, in 
essentially its present form was carried into the field for several 
weeks and both descriptions and keys were checked insofar as possible. 
During 1927-28, opportunity was presented for study in the larger 
American and European herbaria, where many types were consulted. 
Here the matter rested, for, because of theeconomic Stringencies of 
the period, no prospect of publication presented itself and the 
manuscript was put on the shelf and all but forgotten. 
in recent years, increased governmental activity in the eres 
has resulted in an increased need for a flora, Being long out of tovch 
