The crustose lichen Koerberiella wimmeriana (Korb.) Stein was discover
ed from British Columbia, Oregon, and Alaska and represents a new genu
s for the continent. Some of the specimens are richly fertile and have
a smooth, rimose-areolate thallus, but others represent the sterile m
orphotype with isidioid verrucae seen most often in Europe. One specim
en was heavily parasitized by Sagediopsis aquatica (Stein) Triebel, al
so reported here as new for North America.