Lichen What? Crusty!

May 4, 2021

By Pat Loomis, Conservancy Volunteer

Next time you are out in nature, look closely at the rocks!  They may be home to beautiful, colorful splotches called Crustose Lichens.  These are dry, scaly patches of yellow, orange, red, gray or green.  They are one of three types of lichen (the other two being Foliose and Fruticose) that live on rocks.

Lichen and moss-covered rock at Fish Lake County Park in Cheney, WA
How many different types of lichen can you see?

Crustose Lichen is a complex life form, a symbiotic partnership of two separate organisms: fungus and algae. One way these beautiful, crusty lichens benefit humans is their ability to absorb atmospheric pollutants. By extracting toxins from lichen, scientists can determine the levels present in our atmosphere.  Lichens colonize bare rock and lay the groundwork for plants to come later. Lichens are not plants. They are an algae living among filaments of multiple fungi species in a mutualistic relationship.

Lichens do not have roots that absorb water and nutrients as plants do but they do produce their own nutrition by photosynthesis. Crustose Lichens account for 75% of lichens on earth. Look at the rocks in our environment and you’ll be amazed at all the life forms they harbor, and how microscopically beautiful they really are.