(Jan 2016)  Includes photo(s).
 
[From "The Rose Prize of Santa Barbara Botanic Garden and Rosa Adventures Along the Central Coast" by Don Gers, pp. 20-28]
..... I was not aware we had any white flowered native species roses in North America until I saw the entry for "White Prairie Rose", Rosa foliolosa. Probably the rarest wild rose in the United States disregarding the single colony of Rosa minutifolia on Otay Mesa in San Diego county which is very common south of the border in Baja, Mexico. Rosa foliolosa occurs in a few scattered colonies in north Texas, central Oklahoma and just over the borders into Kansas and Arkansas. Every character in the description of Rosa foliolosa from mostly single flowers on very short pedicels of rootspreading plants less than two feet tall with linear glossy leaves and paired thorns at nodes to its pure white flowers were identical to the SBBG Rowntree rose--we have a match! I thought I already knew R. foliolosa since I was growing a plant given to me by former Rose Letter Editor and student of Rosa, Pat Cole which she got from Hilliers in England. It's the red flowered form most often illustrated in Rose literature. Because it had the same tubular stipules as the Swamp Rose, Rosa palustris I assumed it was a western relative of that New England species. So now I believe the "Hilliers foliolosa" is probably a hybrid of palustris and foliolosa since its characters are a blend of both species.