that thick-spiked wheatgrass is a major component of rangelands in the northwest sector of the Great 

 Plains, namely in Montana. 



However, few plant communities have been described in Montana with thick-spiked wheatgrass 

 {Elymus lanceolatus) as the named dominant or codominant. Western wheatgrass is probably the 

 more common plant throughout most of Montana, wheatgrass appears to be the dominant species in 

 some communities on fine textured, shale-derived soils that predominate on BLM lands in southern 

 Carter County, consistent with its distribution as a dominant or codominant in the Yellow Water 

 Triangle of Petroleum and Fergus counties (Jorgenson 1979). 



We provisionally describe two halophytic associations codominated by Elymus lanceolatus: 

 Atriplex gardmri/Elymus lanceolatus and Sarcobatus vermiculatus/Elymus lanceolatus. The latter is 

 previously reported in the literature by Jorgenson (1979). We also refer to this species as dominant 

 or codominant in two other associations, based on our limited sampling data, but treat them 

 conservatively under the names: Artemisia tridentata ssp. wyomingensis/Pascopyrum smithii p.a. and 

 Pascopyrum smithii p.a. They are widely published in the literature as western wheatgrass 

 communities. Finally, we refer to thick-spiked wheatgrass as the dominant in the Pascopyrum 

 smithii-Nasella viridula p.a. that is widely-recognized as a discrete plant association. In Carter 

 County, the shale ridge area in which it was documented may represent an atypical setting such that 

 the thick-spiked wheatgrass dominance does represent a distinct plant association. To unequivocally 

 resolve the community classification status of the later three types, the taxonomic status must first be 

 resolved by collecting voucher material with inflorescences from vegetation study sites and then 

 additional datasets are needed to support recognition of new types. 



There is a separate, related community classification question. It can only be addressed after 

 resolution of the preceding questions. Some plant association/community type keys (e.g. DeVelice et 

 al. 1995) utilize cover by either species interchangeably to arrive at types named after western 

 wheatgrass {Pascopyrum smithii). This idea of wheatgrass species pairs as ecological equivalents has 

 not been rigorously examined, nor has the possibility that they are distinct plant associations. We 

 note Elymus lanceolatus dominance and codominance in the community descriptions and vegetation 

 sampling data as representing our best judgement, while recognizing the need for additional 

 informafion to resolve these questions. 



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