[Butterflies of the Cascade Mountains of Oregon and Washington]

What appears to be a summit blue sunning on rocks atop the summit of Lookout Mountain, Badger Creek Wilderness. It's host plant is the sulphur-fower buckwheat (Eriogonum umbellatum), of which variety hausknechtii is abundant in the area. The underwing markings suggest this could be a Cascadia blue, but it's host plant, parsnipflower buckwheat (Eriogonum heracleoides) is not found at this site, and would be more numerous in the foothills and plains east of the Cascades, about 10-15 miles further east.