oblanceolate, the clawlike base usually exceeding the 

 sepals; filaments about equalling the sepals; anthers 2- 

 2 . 5 mm long; siliques ascending, straight, (2)2.5-4(6) cm 

 long, 1-2 mm broad, tortulose, sessile or subsessile, the 

 stipe not over 0.5 mm long; stigma not lobed. 



3. Diagnostic characters: This and T. panlculatum (another 

 MPSSC not encountered by this project) are most easily 

 recognized by their combination of tap roots, entire, 

 auriculate stem leaves, white to purple flowers, and erect 

 siliques. The two species can be separated based on the 

 dimensions of their fruits and petals, which are larger in T. 

 paniculatum (adapted from Dorn 1984). 



B. GEOGRAPHIC DISTRIBUTION 



1. Species range: "...southeast Washington to California, east 

 to Montana and Wyoming (Hitchcock and Cronquist 1973)." 



2. Montana distribution: Twelve populations have recently 

 been documented in Beaverhead County, including the three from 

 the Tendoy Mountains; see also Culver (1993). One 1951 record 

 is from Flathead County. 



3. Occurrences in the study area: Three populations were 

 surveyed in the basins of Muddy creek and upper Big Sheep 

 Creek. 



C. Habitat 



Hitchcock and Cronquist (1973) describe the habitat as "moist, 

 often alkaline meadows that dry by summer; desert plains to 

 lower mountains." The three populations in the study area 

 occurred in moist or somewhat dry alluvial bottomlands. The 

 Muddy Creek site was in and around a 28 year old exclosure in 

 a heavily grazed drainage (see slide in Appendix E) .The 

 vegetation here was an Artemisia tridentata/Elymus lanceolata 

 habitat type. The soil was fine fluffy clay. Dominants at 

 the other two sites were Juncus balticus and Chyrosthamnus 

 nauseosus with Poa nevadensis at both sites; soils were silt 

 and silty clay. All of the sites, except within the 

 exclosure, were grazed by livestock . 



D. POPULATION BIOLOGY 



The populations are relatively small, with estimated numbers 

 from around 50 to less than 500 plants. At the site along 

 Muddy Creek, plants occurred both inside and outside of the 

 exclosure . In July, plants were mostly in fruit, with a few 

 flowers . 



E. MANAGEMENT CONSIDERATIONS 



The species is uncommon and occurs in small populations in the 

 study area. These are in habitats that are often heavily 



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