Whorled Penstemon (Penstemon triphyllus)

Whorled penstemon is found at low elevations in the hot canyons of the Snake River and its tributaries in the northwest U.S. It generally grows in very rocky soils or cracks in basalt cliffs. It is very similar to Penstemon diphyllus, but the leaves are generally ternate or quadrate while those of P. diphyllus are opposite. Photo from near Lewiston, Idaho