Members of this genus are weakly cracked to distinctly areolate, with a scattered to whole
thalli. Some of the species of this genus are disc-shaped with plicate lobes at the circumference; these lobes may appear chalky white, grayish, greenish or brownish. Some possess
vegetative means of propagation such as
isidia (column-like structures of fungal and algal cells normally found on the top-side or outer cortex of the lichen) and
soredia (structures that produce soralia, granule-like masses of intertwined fungal and algal cells occurring on top of the cortex and on the margins). They have characteristic
ascomata which are mostly immersed but occasionally emergent. They have 4 to 8 spored
asci that are cylindrical to club-shaped. Their
ascospores are typically
ellipsoid to
globose in shape, colorless and thin-walled. They often contain β-orcinol depsidones (
secondary metabolites of lichens) such as
norstictic acid and
stictic acids; others have
fatty acids or
triterpenes. In genus
Aspicilia dramatic changes in growth forms are very common, and some taxa may display extreme transitions within the same population or even changes within the same thallus. ==Classification==