Lichen body (thallus) crustose, resembling a dried smear of light gray paint.Spore-bearing reproductive structures, called apothecia, are usually plentiful, moderately large (about a millimeter across), red brown to orange brown, with a rim the same color as the thallus. The rim is usually bumpy and uneven. Grows on the bark of hardwood trees, especially maples, in partly open areas.

A common lichen on the bark of trees in partly sunny locations. Look for it at forest edges and where trees are not close together.

Crustose lichens with dark apothecia that have prominent rims are usually Rim Lichens (genus Lecanora), and bumpy rim is one of the most common of these in the eastern US. . Relatively large apothecia with the color scheme above and bumpy rims are good identifiers. However, there are many rim lichens that can only be told apart by microscopic or chemical characteristics, so the identification of rim lichens in the field should always be considered tentative.