This is a member of a circumboreal complex seemingly undergoing speciation even as we speak. Our populations are highly localized with the host plant along streamsides in wet and boggy high-altitude meadows. At Donner they occur in a small part of the Lake VanNorden Meadows and also on a couple of small boggy meadows upslope from Clair Tappaan Lodge and Cal Lodge. At Castle Peak they occupy a small portion of Castle Valley. They always co-occur with the much more widespread Greenish Blue, Plebejus saepiolus, and usually fly together in early summer (June-August), visiting the small flowers of native clovers.
The host is Shooting-Star, Dodecatheon jeffreyi (Primulaceae), which usually grows right at the edges of small streams among sedges. Our populations of this distinctive butterfly are very lightly-marked beneath; those from northwestern California are very dark.