Rock Greenshield Lichen (Flavoparmelia baltimorensis)

3 May

Found on a glacial moraine boulder – a medium to large foliose lichen with a yellow green upper surface when dry; lobes rounded without pseudocyphellae; the upper surface with globose, pustule-like growths resembling isidia. Lower surface is black with a narrow brown zone at the margins.

Mainly eastern US distribution; common wherever exposed acidic rocks are present, especially horizontal or sloping surfaces, it is less common on vertical surfaces. This species was formerly lumped with P. caperata.