The UPGMA cluster analysis of the Nei identity values is 

 shown in Figure 1. Populations cluster into two major groups 

 with an overall similarity of 0.96; one group contains C. 

 lonqistylum (L) and putative hybrids (LX, X, Table 1) , the second 

 group contains C^^ scariosum (S) , C^ hookerianum (H) , and putative 

 hybrids. The three pure or largely pure populations of C. 

 lonqistylum (Duck Creek Pass, Deadman Creek, Russian Creek) form 

 a distinct subcluster with a similarity of approximately 0.98. 

 The remaining two populations in the group (Kings Hill [USFS] and 

 Sheep Creek) are represented by small samples consisting of a 

 mixture of L, LX, X, and a single H. 



In the second large cluster, one "pure" C_^ hookerianum 

 population (Lewis and Clark) is the most distinct, and two other 

 "pure" C_i. hookerianum populations (Flesher Pass and Alice Creek) 

 cluster a small sample of hybrids (Moose Park) . In addition, two 

 "pure" C_i. scariosum populations cluster with another small group 

 of putative hybrids. No "pure" C^ lonqistylum individuals were 

 part of the sample in any of the 6 populations in this cluster. 



Species Analysis - In this analysis individuals were grouped 

 by their field identification, i.e. L, H, S, LX, and X. To 

 increase sample sizes individuals for different populations were 

 grouped together. Table 6 identifies the names of the species 

 used in this analysis. Table 7 lists allele frequencies and the 

 number of individuals sampled (N) of each species or hybrid 

 class. Genetic variation statistics for each group are presented 

 in Table 8 and Appendix II. Values of A ranged from 1.3 to 1.7; 

 P varied from 28.6 to 57.1 percent; and H^ ranged from 0.019 to 

 0.123. Nei's (1978) unbiased genetic identity values were 

 calculated for pairwise comparisons of all 5 species or hybrid 

 groups (Table 9) . A UPGMA cluster analysis of this data matrix 

 (Figure 2) has two major clusters: one containing C_^ lonqistylum 

 individuals and those considered hybrids of C^ lonqistylum and C. 

 hookerianum ; and a second cluster of "pure" C^ hookerianum and C. 

 scariosum , which have similarity of 0.99 based on these isozyme 

 loci . 



DNA Analysis 



A preliminary analysis of twentyone Cirsium samples was 

 conducted. These included: 6 "pure" C^ lonqistylum . 5 C. 

 hookerianum from Montana, 1 C^ hookerianum from British Columbia, 

 4 C^ scariosum from Montana, 2 C^ scariosum from Nevada and 

 Oregon, and three hybrids (HX, LX, X) . Fortyseven RAPD loci were 

 scored for each sample. The first 3 principal components 

 accounted for 47% of the variance in the data set (Appendix III) . 

 Figures 3 and 4 display the distribution of samples in principal 

 component space. 



10 



