METHODS 



Locations and methods for reading the transects are provided 

 in Lesica and Achuff (1991). The Mystery Ridge and Mystery Road 

 sites are in the Pryor Mountains, while the Grove Creek site is 

 on the east slopes of the Beartooth Mountains. 



In order to examine differences in population structure, I 

 placed Shoshonea oulvinata plants into one of three size classes: 



(1) juvenile, area of <15 cm^ 



(2) small mature, area of 16-80 cm^ 



(3) large mature, area of >8 cm^ 



The smallest plants observed flowering were 16 cm^. These 

 "immature" plants comprise the juvenile class. Plants larger 

 than 16 cm^ are potentially capable of reproduction and are 

 considered mature. I arbitrarily divided these plants into two 

 size classes, small and large. 



Reproductive rate is the number of plants producing 

 inflorescences divided by the number of plants in the mature size 

 classes. Mortality rate is the number of plants that died 

 between year t and year t+1 divided by the total number of plants 

 present in year t. Recruitment rate is the number of new plants 

 appearing between year t and year t+1 divided by the total number 

 of plants present in year t. 



Some plants that were recorded as more than one individual 

 in 1991 were recorded as one in 1992 and vice versa. 

 Consequently, changes had to be made in the 1991 summary 

 statistics, so what is presented this year for 1991 will not 

 match what was presented in Lesica and Achuff (1991). 



RESULTS AND DISCUSSION 



Shoshonea pulvinata size class distribution at the three 

 sites in 1991 and 1992 are presented in Figure 1. At each site, 

 size class distribution was similar both years; however, it was 

 very different at the three sites. Grove Creek in the Beartooth 

 Mountains had a large proportion of immature plants and few large 

 reproductive plants. Mature plants, especially small mature 

 plants, dominated the populations at the Mystery Ridge and 

 Mystery Road sites in the Pryor Mountains. 



The Grove Creek transect population increased between 1991 

 and 1992, while the two sample populations in the Pryor Mountains 

 declined (Table 1) . The percent of mature plants producing 

 flowers varied between 37% and 71% and was indistinguishable 

 among the three sites (Table 1) . The Mystery Ridge site, which 

 had the highest proportion of large mature plants (Figure 1) , had 



