Fuscidea muskeg is a species of crustose lichen in the family Fuscideaceae.

The type species was collected in the Hoonah-Angoon Census Area of Glacier Bay National Park.

The soralia are initially discrete, but aggregate later, and in some instances form a granular layer throughout the thallus surface.

[1] The photobiont partner of Fuscidea muskeg is trebouxioid – a spherical, one-celled green alga.

The results of standard lichen spot tests are thallus PD+ (yellow), and C+ (red).