Dog Lichen

Dog lichen, or pelt lichen, is the common name for Peltigera, a genus of roughly one hundred species of foliose lichens. They form broad, lobed growths with upper surfaces ranging from gray to brownish, sometimes reaching thirty centimeters across, and grow mainly on soil but also on moss, tree bark and rock on every continent. Most Peltigera species partner with nitrogen-fixing cyanobacteria rather than green algae, making the genus ecologically important for adding nitrogen to the soils it colonizes.