The body of this blue-grey to greenish lichen is thin and powdery and lacking any lobes or medulla and is composed of tiny granules.
Found in shaded places, on acid rocks, walls, posts, and tree trunks. A widespread and very common species.
Photograph of Dust Lichen (Lepraria incana), taken February 2012 on old Willow, local river, Staffordshire. © Pete Hillman 2012. Camera used Panasonic Lumix DMC-FZ38.