Cinder Lichen

Cinder Lichen is a common sunken disk lichen. It occurs worldwide on every continent including Antarctica. It is most common in North America and Europe. It occurs throughout the United States, but it is mostly absent from the Great Plains and the Great Basin. It is common in Minnesota.

Cinder Lichen grows in open areas on rock that has silica (SiO2) as its principal constituent (siliceous), including granite, slate, sandstone, quartzite, brownstone, bluestone, and volcanic rock.

The vegetative body (thallus) is thin to thick and ⅝″ to 6″ (1.5 to 15 cm) in diameter. It is separated by cracks into distinct, island-like areas (areolate). The islands (areoles) are usually angular, sometimes irregular, flat or slightly convex, and 1⁄128″ to 1⁄16″ (0.2 to 2.0 mm) wide and more or less round. They are closely spaced, almost touching, but separated by distinct cracks. The upper surface is gray, whitish gray, or almost white, sometimes slightly tinged with yellow.

Spore-bearing reproductive structures (apothecia) are usually numerous. They are 1⁄256″ to 1⁄16″ (0.1 to 1.6 mm) in diameter. The disk is usually black, rarely brownish black, and it is usually concave, sometimes flat, rarely convex. It is flat with the surface of the thallus. This is the feature that gives the genus its common name. It sometimes has thin white dust (pruinescence) on the surface, but it usually does not. A single areole may have 1 to 3, rarely up to 10 apothecia, and these blend together.

Rock

Crusticose

Open areas

Siliceous rock, including granite, slate, sandstone, quartzite, brownstone, and bluestone

Sources

4, 24, 26, 29, 30, 77, 81.

Common

Dan W. Andree
3/13/2025

Location: Frenchman’s Bluff SNA