Aspicilia contorta (aka “Chiseled Sunken Disk Lichen”)
Description: Thallus dark olive to olive-gray, thick, areolate, with hemispherical to “chiseled” areoles that are contiguous or dispersed, often with depressed, white pseudocyphellae. Apothecia deeply immersed, pruinose, usually one per areole; spores broadly ellipsoid to spherical, 20-30 x 15-25 um, 4 per ascus.
Chemistry: All reactions negative (no lichen substances).
Substrate: On noncalcarous or calcarous rock.
Lookalikes: The areoles of A. contorta, although sometimes contiguous, are not radically oriented or bordered by a distinct prothallus as in A. calcarea, a very similar widespread species on limy rocks.
Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff
Database Entry: Distance Everheart 12-26-13