Parmelia barrenoae

Parmelia barrenoae is a species of foliose lichen in the large family Parmeliaceae. It was formally described as a new species in 2005. Before this, it was lumped together as one of several lichens in the Parmelia sulcata group—a species complex of genetically distinct lookalikes. Parmelia barrenoae is widely distributed, occurring in Europe, western North America, Africa, and Asia. The greenish grey to whitish grey leafy thallus of Parmelia barrenoae grows up to 10 cm (4 in) in diameter. Features of the thallus surface include tiny pores for gas exchange, and vegetative propagules called soralia. The lichen usually grows on tree bark, but is occasionally found on moss-covered rocks in open and sunny places. The lookalike species Parmelia submontana and Parmelia sulcata can be distinguished from Parmelia barrenoae by small differences in morphology. Studies indicate that Parmelia barrenoae is sensitive to air pollution, and it has been proposed for use as an indicator of well conserved......read more on Wikipedia.