2. POPULATION SIZE 2VND CONDITION: In the Limestone Hills, the total 

 estimated range in numbers of plants within ten miles of ridge 

 system is between 1800-3600 individuals. The subpopulation 

 totals are five to ten times greater on the western ridge 

 compared to the eastern ridge. The total population size is 

 large for this species, and the prevailing undisturbed habitat 

 provides good condition. The occurrence has been assigned a rank 

 of "AB" because of the uncertainties of long-term viability and 

 def ensability for what is otherwise an excellent example. 



The largest populations and the largest number of populations are 

 found in the Pryor Mountains, where it is sometimes locally 

 common, and very widely distributed (Lesica and Achuff 1991) . It 

 is also locally common in at least part of the Big Horn Canyon 

 National Recreation Area (Lesica pers. commun . ) . 



3. REPRODDCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: Disk flowers are diecious, made up of 

 pistils and stamens in a perfect flower. Ray flowers are 

 strictly pistillate. Outcrossing takes place; it is not known 

 whether the disk flowers are also capable of selfing. 



There was no evidence of asexual reproduction, though apomixis 

 cannot be ruled out. 



b. POLLINATION BIOLOGY: The only pollinators observed during the 

 survey were bumblebees (Subfamily Apinae; see Section VI. 

 Photograph A) . 



c. SEED DISPERSAL AND BIOLOGY: The bristly pappus augments wind 

 dispersal of seeds. The light seeds moves on wind gusts over 

 short distances along ridges and down slope. Wind is probably 

 also the long-distance dispersal vector, considering the exposed 

 habitat and the strong wind currents along ridges. 



Seeds mature in early summer. It is not known whether they have 

 a dormancy or germinate in the fall. Seed "safe sites" are found 

 on bare substrate, often between cobbles representing slightly 

 moderated microclimate. 



G. POPULATION ECOLOGY 



1. BIOLOGICAL INTERACTIONS 



a. COMPETITION: The short stature of sword townsendia and its 

 presumed level of dependency on early spring precipitation 

 restrict it to sparsely vegetated settings, and make it a poor 

 competitor. The most abundant plant species in the localized 

 habitat where it grows are also short perennials. Grasses and 

 shrubs making up little more than a trace of canopy cover. 



