Verrucariaceae Verrucaria murina Growth type crustose Chemical results negative Can be frequent in urban and rural habitats on siliceous stones and rocks, bricks, chalk and limestone. Thallus usually forms small, thin, green or dark brown patches with +/- prominent perithecia. Spores (14)18-24(28) x (6-)8-11(14) µm. Microscope photograph below. Similar: V. dolosa occurs in similar habitats but has smaller spores

Microscope photograph

Verrucaria murina
Lychett Matravers, Dorset. January 2014