Limestone Hills species list (cont.) 



Phlox alyssifolia 

 Poa secunda 

 Potentilla fruticosa 

 Purshia tridentata 



Note: A thorough floristic list of plant species observed in the 

 Limestone Hills has been prepared by Scow and Culwell (1993), 

 with minor species additions made in the course of this study 

 (annotated species list on file) . 



The mountain mahogany potential habitat of sword townsendia 

 represents northern extensions of Great Basin vegetation, within 

 a matrix of other biogeographically-interesting Great Basin 

 vegetation. It was noted that the Artemisia nova plant community 

 positioned along toeslopes of the Limestone Hills may represent 

 its northernmost range extent. The biodiversity significance of 

 this vegetation may warrant separate consideration. 



In the Pryor Mountains, sword townsendia is found in mountain 

 mahogany woodlands and cushion plant grasslands associated with 

 Agropyron spicatum . Ceratoides lanatus . Phlox spp. and Cryptantha 

 cana (Lesica and Achuf f 1991) , as well as in openings among 

 widely-spaced Pinus f lexilis and Psuedotsuga menziesii . 



2. TOPOGRAPHY: In general, sword townsendia occupies ridge crests. 

 Its highest numbers are on broad, flat, exposed ridge summits 

 (Section VI. Photograph C) . The ridge crests are typically part 

 of foothills settings. 



In the Limestone Hills, broad, flat expanses of ridge summit are 

 uncommon. Most sword townsendia subpopulations are on narrow 

 bands or along narrow ridge crests (Section VI. Photograph D) . 



The original Limestone Hills discovery of sword townsendia was 

 made at a midslope position where it was very rare (Lesica et al. 

 1986) . Two small midslope sites were relocated in the vicinity 

 of the original collection site during this study (Section Vi. 

 Photograph E) . 



On the ridge top above the midslope plants were found much higher 

 numbers and densities of the species. The ridge crests form 

 discontinuous population cores, highly localized on any given 

 ridge segment. 



A toeslope subpopulation was also found in Sec. 10 of T.6N R. IE 

 (Section VI. Photograph F) . Midslope and toeslope plants 

 represent population satellites, where seeds chanced upon 

 unvegetated substrate. These satellites are small subpopulations 

 which are probably short-lived, as judging by the few that were 

 found, and their low densities. 



