1. ASSOCIATED VEGETATION: Juncus hallii has been 



reported from montane to alpine moist grasslands 

 and sedge meadows. Common associates at the Big 

 Belt Mountain site were Calamagrostis canadensis , 

 Carex scopulorum . Carex microptera . and Senecio 

 foetidus . Other associated species were Phleum 

 alpinum . Juncus nevadensis . Deschampsia cespitosa . 

 Carex rostrata . Danthonia intermedia , Agrostis 

 scabra . Epilobium watsonii, Spiranthes cernua . 

 Antennaria corymbosa . Aster occidentalis . and 

 Pedicularis qroenlandica . 



2. TOPOGRAPHY: Juncus hallii occurs on flats or 



benches on gentle mid to upper slopes with 

 elevations ranging from 4000-8400 feet. At the 

 Big Belt Mountain sites, the species was on a 

 level wetland setting in the Birch Creek headwater 

 basin below The Needles at 7420 feet elevation 

 (Figure 12) and in a small sloping wet meadow 

 above the Birch Creek headwater basin, located on 

 the lower slopes of a mountain. 



3. SOIL RELATIONSHIPS: Only one Montana site has soil 



information, and the soil is classified as a silt 

 loam. Parent material at the Big Belt Mountain 

 sites was alluvium. At The Needles site Juncus 

 hallii occurs near a sphagnum bog. In the other 

 site, it occurs close to a headwaters stream 

 rivulet. 



4. REGIONAL CLIMATE: The climate of west-central 



Montana can generally be classified as cool, dry, 

 and continental, with locally greater amounts of 

 precipitation in the mountains. The closest 

 weather station to the Big Belt Mountain 

 populations of Juncus hallii is about 20 map miles 

 southwest at Townsend which is much lower in 

 elevation at 3833 feet. For the period of 1951- 

 1980, the mean annual precipitation at Townsend 

 was 11.11 inches, the mean January temperature was 

 19.7°F, and the mean July temperature was 66.8°F 

 (U.S. Department of Commerce 1982.) 



POPULATION DEMOGRAPHY, BIOLOGY AND SPECIATION 



1. PHENOLOGY: Juncus hallii flowers in July to August 

 (Hitchcock et al. 1969). 



48 



