Names: Amygdalaria panaeola, Powdery Almond Lichen
Color: Pale brownish gray to yellowish pink.
Cephalodia: Dark pink or olive (depending on the photobiont) brain-shaped galls on or between the areoles.
Chemistry: Soralia C+ red; cortex PD-, K-, KC+ red, C+ red (rarely C-); medulla PD-, K-, C-, KC- (gyrophoric acid often with confluentic acid & related compounds).
Substrate: Rocks in high altitudes in Arctic; humid rock faces such as those near waterfalls when in lower elevations & latitudes.
Range: All but eastern Alaska, west coast of Canada, northeast US & Canada as well as eastern Canada.
Lookalikes: This lichen is almost always sterile & is best distinguished from most other sterile crustose lichens on rocks by its combination of cephalodia & soredia, & by its chemistry. Coccotrema pocillarium is a sorediate, usually sterile crustose lichen on bark in humid coastal forests of the Pacific Northwest. It contains stictic acid (PD+ orange, K+ yellow). Most other species of Amygdalaria are relatively rare & are confined to the humid northwest coast from Washington to southeastern Alaska.
Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff
Database Entry: Distance Everheart 12-26-13