A foliose (leaf-like) lichen, attached by rootlike structures called rhizines underneath. Upper surface gray to gray brown, greener when wet. Inside (the medulla), pale to bright yellow or orange yellow (below right), hence the common name. Clumps of bluish powdery material, called soredia, on the surface (top, left). This powder is made of minute balls containing both fungus and algae, and can fall off, be rubbed off, or blow off and grow into new lichens. Tips of lobes with tiny white spots (below left and right), called pruina that are made of crystalline material. Found on bark, or rarely on rock. Thhe specimen photographed was on a stump of a fallen tree and was removed for identification.

A common lichen of the eastern United States. It occurs in Wildwood, but we do not know how common it may be there.

It would not be easily identified at first glance, as it is pretty non-descript gray to brown gray. Look for the tiny pruina on the lobe tips, and the balls of bluish soredia. To confirm, look for broken lobs that might show the yellow medulla, or carefully break off a lobe tip.