Porpidia cinereoatra

Growth type crustose
Chemical results: Medulla K-, C-, P-

Can be locally common on exposed siliceous rocks, particularly in upland and coastal areas

Thallus cracked to areolate, creamy-white or greyish, the black prothallus +/- visible. Apothecia large, often remaining partly immersed, discs black, blue-grey pruinose when young. Epithecium brownish-green.

Similar: Porpidia macrocarpa, medulla K+/- yellow, P+/- orange.
Porpidia crustulata, K+/- yellow, P+/- orange

Porpidia cinereoatra
Lychett Matravers, Dorset. January 2014

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