the Ovales subgenus. The Bracteosae subgenus has androgynous spikes while the other has 

 gynecandrous spikes. A hand lens or microscope and technical key are essential for positive 

 determination. 



C. GEOGRAPHICAL DISTRIBUTION 



1. GLOBAL RANGE: Pennsylvania to Saskatchewan, south to Virginia, 

 Missouri, Texas, and New Mexico. 



2. STATE DISTRIBUTION: Known only from 4 collections including the 2 

 study area sites in Powder River and Rosebud counties, and from 2 collections 

 in Big Horn County (Figure 8). 



3. STUDY AREA DISTRIBUTION: The two kno\vn sites are at north and 

 south ends of the District, at the heads of tributaries into the Tongue River 

 (Figure 8). The southern site is at the head of Hay Creek above O'Dell Creek; 

 the northern site is at the head of a side draw above the East Fork of Otter 

 Creek. The species was sought in many areas in conjunction with surveys for 

 Carex torreyi; it is rare and highly localized, however. 



D. HABITAT 



ASSOCIATED VEGETATION: Carex gravida occurs locally in mesic 

 deciduous vegetation associated with watercourses (Appendix E-6). In the 

 Ashland District, both sites were within a valley otherwise dominated by 

 ponderosa pine. The East Fork of Otter Creek site (004) had scattered tall 

 shrub thickets of ser\'iceberry and a stand of quaking aspen. The Hay Creek 

 site (002) was heavily shaded in its valley setting, with scattered tall 

 chokecherry and graminoids. The two sites of tall shrub communities are not 

 well-developed plant associations but are closely associated with woody draw 

 types. Associated species for the study area and Big Horn County are as 

 follows: 



Amelanchier alnifolia 

 Apocynum androsaemifolium 

 Carex hoodii 

 Carex sprengelii 

 Carex torreyi 

 Crategus columbiana 

 Fraxitms pennsylvanica 

 Poa interior 

 Poa pratensis 

 Popidus tremuloides 



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