Foliose lichen. Thallus foliose, grey even when fresh, but can be vivid green when wet, margins dark brown, glossy (not pruinose), underside cream to brown, lobe surfaces with puntate, white dots (pseudocyphellae) that develop into well-delimited, round, laminar soralia, thallus margins sometimes also becoming sorediate later; apothecia said to have red-brown discs, but very rare. Widespread and locally common on a variety of trees, spreading into urban areas with the reduction in sulphur dioxide pollution.
On the bark of a Holm oak tree
Camera Model: NIKON D300. Exposure Time: 1/60 sec. f/36 ISO Speed Rating: 200. Focal Length: 90.0 mm. Flash fired