East and West Buttes have differences in their floras that may 

 correspond with substrate differences. Preliminary efforts were made 

 in characterizing the distinctions by noting which taxa occur on which 

 butte, augmented in transcribing information from the incomplete 

 copies of field collection records of Larry Thompson (in progress). 



There are likely to be significant numbers added to this flora with 

 further study, so it is still referred to as a preliminary flora. An 

 addition of 64 species was made through this project, representing 

 almost no late-flowering activity. Flowering of early-flowering 

 plants under the 1993 weather conditions was profuse and prolonged 

 into the middle of summer. July 12 marked the last day of 1993 

 fieldwork in the Hills. 



Previous works characterized the biogeographic affinities of the 

 Sweetgrass Hills flora as divided between the Rocky Mountains and 

 Northern Great Plains influences (Thompson and Kuijt 1976, Western 

 Technology and Engineering 1989) . In addition, there is a distinct 

 Great Basin influence, lying mainly outside of the study area, and 

 particularly developed in communities dominated by greasewood 

 r sarcobatus vermiculatus ) , silver sage ( Artemisia cana) and long- 

 leaved sage ( Artemisia lonqifolia ) . There are also small components 

 of Columbia Basin, boreal, and eastern deciduous woodland affinities, 

 as well as widespread wetland plants whose center of distribution, 

 much less of origin, are unknown. Further investigation into the 

 biogeographic affinity of the Sweetgrass Hills is warranted. 



The previous list of alpine and subalpine plant taxa which may 

 represent range extensions in the Sweetgrass Hills warrants editing 

 and expansion, and the entire floristic list edited to indicate which 

 species are represented by voucher specimens. 



Vegetation 



Vegetation of the Sweetgrass Hills has been described in general 

 physiognomic terms and by forest dominance types (Thompson and Kuijt 

 1976, Western Technology Engineering, Inc. 1989), further 

 characterized as to elevation range and area extent (Thompson 1978) . 

 The Sweetgrass Hills have not been included in any statewide forest, 

 prairie or riparian sampling studies or classifications except for a 

 study plot taken from the Gold Butte Cemetery ("Middle Butte") in 

 Festuca scabrella/Stipa viridula habitat by Ross et al . (1973) as part 

 of the effort to characterize state range sites and range site 

 potentials. There have been preliminary efforts to enumerate the 

 vegetation series, habitat types and community types of the Sweetgrass 

 Hills in comparison with other outlying ranges of the region (Western 

 Technology and Engineering, Inc. 1989) . The following observations 

 augment these general community descriptions. 



Upper elevation mesic slopes are predominantly Festuca scabrella 

 habitat types w/wo codominance by Potentilla fruticosa , referred to as 

 the montane grassland by Thompson and Kuijt (1976). The exceptional 



