Lecanoraceae Lecidella stigmatea Growth type crustose Chemical results: Thallus K +/- yellow, C-, P-, UV- Common on cement, mortar, urban walls and paths and on base-enriched or weakly calcareous siliceous rocks. Very variable. Thallus pale grey, whitish or stained green, evanescent, cracked or +/- areolate. Apothecia have dark brown or black discs, margins becoming excluded. Epithecium purple-brown, hypothecium pale yellow or colourless. Spores simple, 10-16 x 6-9 µm. Micro photograph below. Similar: Clauzadea monticola has a reddish-brown hypothecium

Microscope photograph

Lecidella stigmatea
Parkstone and Sturminster Marshall, Dorset. March 2012 and 2014