43 



6. Locations known or suspected to be erroneous 



reports: See Table 7, pp. 44-46, for detailed 

 occurrence records and information on the 

 following site. 



a. Idaho: Although not yet verified, the 

 Rock Flats (003) site is believed to 

 actually be located near Macall in Adams 

 County, Washington. The original specimen 

 label appears to have been misinterpreted. 



C. Biogeographical and phylogenetic history: Silene 



spaldinqii is associated with Palouse prairie. The 

 soils supporting these communities were deposited 

 approximately 15,000 years ago through multiple 

 flood releases of Glacial Lake Missoula and Glacial 

 Lake Kootenai (Alt and Hyndman, 1986). Soils and 

 debris were deposited from Montana across Idaho and 

 into Washington and Oregon. It is possible that 

 this species evolved after the soils were deposited 

 or it may have migrated into these areas after the 

 waters had receded. 



General environment and habitat description. 



A. Concise statement of general environment and 

 habitat: Silene spaldinqii is restricted to Festuca 

 idahoensis habitat types and phases throughout its 

 range (Heidel, 1980). These areas are also often 

 referred to as Palouse prairie. Populations in 

 Montana occur most often on north- to east-facing 

 slopes, in or along small drainages (without running 

 water) or in swales. Soils are silty loams, 

 moderately deep and sometimes gravelly. These sites 

 often occur along the lower treeline, or near 

 scattered trees. The vegetation is dominated by 

 grasses ( Festuca scabrella (rough fescue) and 

 Festuca idahoensis (Idaho fescue)) with scattered 

 shrubs ( Rosa woodsii (woods rose)). In Montana, S. 

 spaldinqii occurs at elevations of 2,700-3,500 feet. 

 The slopes where it occurs are likely to catch and 

 maintain snow throughout the winter. 



B. Physical characteristics. 



1. Climate. 



a. Koppen climate classification: Type Dfb, 

 a Canadian climate with snowy winters and 

 moderately warm summers, with needle- 

 leaved trees in the north (Visher, 1954). 



