In southern Alberta we see Cladonia that could fit the morphology of your specimen Rebecca - granular soredia grading to microsquamules, often with partially corticate podetial base, primary squamules may or may not be present, occasionally with narrow cups and proliferations. We've identified them as Cladonia rei, and all 100 or so we've examined to date are PD-, UVfaintBW, with TLC confirming homosekikaic acid. In other regions Cladonia rei also contains fumarprotocetraric acid. I've seen some similar specimens from Idaho from grassland habitats - would rei be another option in your area? I posted a representative photo as well, growing on Selaginella densa.