GENERAL DESCRIPTION OF THE REGION AND ITS VEGETATION 
Topography and Climate 
The flora of northern Idaho, as delimited in this paper, 
treats of the vegetation of that part of the state north of, and in- 
cluding the drainage of the North Fork of the Clearwater River, as 
well as the small part of the Uniontown Plateau immediately north of 
the main stream in the vicinity of Moscow and Genesee; the area is 
about equal to that of Vermont. The Clearwater River, which is a 
tributary of the Snake River, has its origin by three principle 
branches in the Bitter Root and Clearwater Mountains* and flows from 
east to west at a distance approximately 140 miles south of the Cana- 
dian Boundary. The North Fork mentioned above, joins the main stream 
near the town of Orofino. The greater part of the region thus delin- 
ited is mountainous and is characterized by a forest flora of which 
the western white pine, Pinus monticola, is an important and charac- 
teristic constituent. Inasmuch as the natural floristic and physio- 
graphic limits of the white pine forest are not clearly defined, po- 
litical boundaries have been preferred for practical reasons, although 
floristic elements distinct and very different from those of the white 
pine forest have necessarily been included. 
The eastern and southern boundaries which have been chosen 
coincide in general with the limits of the white pine type. This 
type reaches its greatest development south of the Clark Fork of the 
* Nomenclature after I. Bowman 
