Arctoparmelia centrifuga (aka “Xanthoparmelia centrifuga” or “Concentric Ring Lichen”)

Location Summary

Range: Mainly arctic & boreal south to central British Columbia.

Identification Characteristics

Description: Lower surface pale.  Lobes flat to slightly convex, 1-2 mm wide, without soredia or isidia; lower surface white or almost white, with scattered dark rhizines.

Apothecia: Fairly common.

Lookalikes: The white lower surface distinguishes this lichen from the much rarer Arctoparmelia separata & Arctoparmelia incurva; both have a mouse-gray lower surface, & Arctoparmelia incurva produces large, irregular sorelia on the upper surface.  Rarely, Arctoparmelia centrifuga lacks usnic acid & a gray instead of yellow-green, with the cortex reacting K+ yellow, KC-.

Utility Uses

In the Arctic, Arctoparmelia centrifuga has been used as a source of red-brown dyes for wool.

Bibliography: Macrolichens of the Pacific Northwest, by Bruce McCune & Linda Geiser, Lichens of North America, by Brodo, Sharnoff, & Sharnoff

Database Entry: Distance Everheart 12-26-13