1.0 INTFDDUCTION' 



The Sv;eet Grass Hills proposed Area of Critical Environrrental Concern 

 (PACEC) ccmprises about 3,220 hectares of Bureau of Land KanageiTent 

 surface in Toole and Liberty counties of north-central Montana (Figure 

 1). The Hills are the smallest and, in many respects, the most 

 isolated of the intrusive "island" mountain ranges of the northern 

 Great Plains (Thcrrpson and Kuijt 1976a). High peaks rise abruptly from 

 the surrounding prairie, supporting montane to sutelpine plant 

 ccrmrunities . Elevations within the PACEC range frcm about 1340 m to 

 over 2100 m en tog of Vfest Butte. The geographic position, rugged 

 topography and elevational range support a diversity of plant 

 ccnrnunities more closely related to the Rocky Mountains than the 

 Northern Great Plains. The presence of both floras results in a unique 

 ass3Tiblage of plant ccrrmunities . 



The purpose of this inventory was to assess the status of any rare 

 plants potentially occurring within the PACEC. Secondary objectives 

 v.'ere to generate a cctrprehensive species list and briefly describe the 

 major plant carrnunities of t2~e PACEC. 



