METHODS 



Sampling Procedures 



Leaf samples of Cirsium longistvlum were taken from seven 

 study sites representing major population centers and a full 

 range of morphological variation (Table 1) . Collections were 

 made of green leaf material on flowering stems, using the 

 freshest available intact leaves, usually upper stem leaves. A 

 minimum of two leaves were collected, sealed between damp paper 

 towels in zip-loc plastic bags, labelled with an unique 

 sequential number, stored on ice, and mailed in overnight mail to 

 the University of Idaho. The bract category was recorded for 

 each sampled individual as delimited in Poole and Heidel (1993). 



At all sites of Cirsium lonqistylum , collections were made 

 within a circular plot of 10 m radius, except for Russian Creek, 

 with a 20 m radius. The sample areas corresponded to circular 

 demographic monitoring plots at four of the seven sample sites 

 (Heidel 1994). Sample size was a minimum of 20 plants per site, 

 and included all flowering plants in the plot. Actual sample 

 size ranged from 24 (Kings Hill #2-USFS) to 38 (S. Fk. Deadman 

 Cr.) per site, though in most cases fewer than 15 plants were 

 used per set for preliminary genetic analysis. 



Six of the seven sample sets from the Little and Big Belt 

 Mountain ranges represent discrete population at least 2 airmiles 

 (3.2 km) apart. The Kings Hill pair of samples were collected 

 from two adjoining segments of the population in monitoring plots 

 from contrasting habitats. 



Leaf size and condition varied between sites and within 

 sites. The degree of inflorescence branching varied widely 

 between plants, and upper stem leaf size was significantly 

 smaller on the more highly-branched plants. Many stem leaves 

 remained green through August in the exceptionally cool and moist 

 season of 1993, but herbivory and rapid decay in storage markedly 

 reduced usable leaf material. 



Leaf samples of Cirsium hookerianum were collected at two 

 sites over 30 miles (48 km) beyond the known range of Cirsium 

 lonqistylum at Flesher Pass (Schassberger #464 iCronquist) and 

 Lewis and Clark Pass in the Blackfoot Range. Leaf samples of 

 Cirsium scariosum were collected at one site over 50 miles (80 

 km) beyond the known range of Cirsium lonqistylum at Warren Pass 

 in the Anaconda Range. These samples were collected in the first 

 week of September when only basal rosette material retained 

 living tissue. 



DNA from herbarium specimens of Cirsium hookerianum from 

 Pondera Co., MT (Hitchcock #18177) and Williams Lake, British 

 Columbia (Calden #17953) and of C. scariosum from Nye Co., Nevada 



