Aspicilia phaea (dusky sunken disk lichen) is a grayish brown to tan areolate crustose lichen commonly found on rock in coastal to inland parts of central and southern California.

[2] In rare cases full areolas do not form, and it appears as being cracked (rimose).

[2] The areolas are irregularly sized and angular, giving the lichen body (thallus) the appearance of a mosaic of small polygons.

[1][2] A rim of dark tissue (prothallus) may surround the edges of the lichen.

[1][2] The fruiting body parts (apothecia) are flat to concave (especially in the thallus center), and slightly immersed in the thallus, appearing as sunken round to polygonal discs, often with a grey or white rim of thalline tissue.