Physconia grisea

Description:

Foliose, thallus green when wet, drying grey or brown-grey, but densely white-pustulate pruinose over the whole surface, medulla white, margins coarsely sorediate, undersides with long rhizines, which are single to tufted and usually fused at the base but then the majority unbranched, pale or becoming blackish; apothecia uncommon, with pruinose, grey-blue disks and sorediate margins.

Habitat:

Widespread and often common on stonework, or tree bark, especially when the latter is dust-impregnated.

Notes:

Camera Model: NIKON D300. Exposure Time: 1/2 sec. f/32 ISO Speed Rating: 200. Focal Length: 90.0 mm. Flash fired