Note: Herbarium specimens in Oryzopsis hymenoides folders have been checked at 

 MONT (Rumely pers. conimun.) and at MONTU (Heidel pers. obs.) without finding 

 additional collections for annotation to O. contracta. This information has been sent to the 

 Beaverhead National Forest, which maintains a small herbaria with collections from 

 southwestern Montana. 



Local distribution: One large site was documented for the species on private land at the 

 lowest end of the Garden Creek Allotment, on the southeast edge of the Ruby Mountains 

 project area. It spamied over 100 acres across an area o\tx 1/2 mile long in T7S R5W Sec. 

 34, and is likely to extend onto adjoining lands under mixed public/private ownership. 



HABITAT: The Ruby Range study area has the largest known population to date, so its habitat 

 is described in detail first and is used for comparison with all other sites. It falls within the 

 documented range of habitats in Wyoming, summarized as dry, shallow, sandy, or gravelly soils 

 on slopes or rolling plains in open, sagebrush-grassland communities (Fertig 1 994). The study 

 site is a very dry setting, on shallow sandy to silty soils, over a variety of topographic positions 

 across rolling grassland knolls, small silty outcrops, and uplands suiTounded by sagebrush steppe 

 at the interface between the montane and intennontane zones. It is on 0-20% slope, with a 

 predominantly gentle slope and southeast aspect but all compasspoints included. In Beaverhead 

 County the topographic positions of Oryzopsis contracta were on mid to lower slopes (0-30%) 

 with most commonly south and west aspects, but in Pondera County, the small population was 

 restricted to a ridgetop. The known range of elevations in Montana is 3890-7000 ft. with the 

 lowest elevation site in Pondera County and the highest elevation site at tlie historic Beaverhead 

 National Forest collection in the Tendoy Mountains. 



Soils are consistently well-drained and light-colored, often with little or no profile development. 

 They are derived from a wide variety of parent materials including Madison Group limestone, 

 siltstone, alluvial gravel or sand, and quartzite. In the study area they are mapped as Trudau loam, 

 2-8% slopes (USDA Soil Conservation Service 1989), representing a silty colluvium. 



37 



