I 

 I 

 I 

 I 



I 



I 



I 

 I 

 I 

 I 



i 

 i 



i 



B. 



D. 



Present legal or other formal status 



1. Federal 



A. U.S. Fish and Wildlife Service: none, 



B. 



U.S. Forest Service: 



none 



C. Bureau of Land Management: none 



2 State: This species has a state rank of "SI" indicating 

 it- may be critically imperiled, based on only two known 

 populations with limited populations. 



C. Geographical distribution 



1. Species range: Great Plains 

 endemic, extending from North Dakota 

 to Nebraska, eastern Wyoming and 

 Montana. In keeping with the 

 treatment of Mulligan (1968) it is 

 known from five states in a 

 relatively narrow range marking 

 that of a regional endemic. n 

 previously cited as 

 didvmocarpa in the Great 

 reported from Harding, 

 Jackson and Sheridan counties, SD, 

 and Billings, McKenzie and Slope 

 counties, ND (Great Plains Flora 

 Association 1977) . Later, it was 

 apparently mistakenly reported for 

 the northern Rocky Mountains (Great 

 Plains Flora Association 1986) when 

 correctly treated as P. 

 brassicoides . 



p. BRASS/CO/Df S 



. count 



MONTANA 



NORTH 

 DAKOTA 



Physaria 

 Plains, 

 Haakon, 



SOUTH 

 DAKOTA 



NEBRASKA 



Distribution of P. brassicoides. 



(Mulligan 1968) 



2. Montana distribution: Phvsaria brassicoides is now known 

 from two populations in Carter County, discovered as an 

 addition to the state flora in the course of this study, it 

 included in Dorn (1984) as "expected" in Montana, being 



is 



known from adjoining counties in Wyoming, 



3. Occurrence in the study area: Both populations of Mustard 

 twinpod are in the Ekalaka Hills. It was not found in the 

 South Dakota units. 



Habitat 



1. Associated Vegetation: The species occurs on steep, 

 sparsely vegetated slopes of ridges, within valley systems. 

 Most of the substrate is barren, but there are clumps of 



49 



