Agricultural Engineers?

You might not think of a lowly lichen as an engineer. Most people might laugh at the idea. A few though would know their story.

Frog Pelt Royalty free images from


Lichens are fairly common on the moist Pacific Northwest central coast. One can find them growing on mossy rocks, soil, and dead trees in moist areas typically under the 2,200-foot elevation.

If we were to travel north into Canada, we could find areas hosting nearly 30 different lichen species. We could even find some in northern California.

Would we see them?

Peltigera lichens are found on all continents. There are several different types of lichens that includes over 580 species of macrolichens and over 1,400 species of microlichens. Our region is particularly rich in lichens.

Easy to Overlook

Frog Pelt or Dog Lichen is commonly found in the Pacific Northwest. This small lichen is easy to identify.

Frog pelt creates relatively large rubbery olive green-gray lobes. The lobs are typically between .04 and .9 inches wide and nearly flush to the ground.

What makes them special?

Lichens are ecologically important as food and shelter for wildlife, large and small, and indigenous Americans

Lichens are fairly intolerant of environmental change and are very sensitive to changes in air quality, moisture, and drainage. They won’t thrive in dirty air.   


All lichens share a common ancestry and all Peltigera associate with nitrogen-fixing cyanobacteria Nostoc. This association allows them to pull nitrogen from the atmosphere.

Nitrogen is required for healthy plant growth. It is often in short supply in forests. In more arid lands, lichens help stabilize soil and sand.  

Other Uses

Peltigera lichen have been used medically. This includes: Treating wounds, urinary disorders, thrush, cough remedies, tuberculosis, antioxidant, and rabies.

Dog lichen is not typically a mammal food source.

An Engineer?

Lichens are a hard working combination of fungus and algae. They have evolved from a simple scavenging fungus to a lichen by cultivating a ‘symbiotic’ (or mutually beneficial) relationship with algea.

Algea creates the food. The fungus provides the protection and support structure. This organism can live several centuries.

Keep in mind, this sometimes disheveled-looking plant has no roots, stem, flowers, or leaves. It depends on slender holdfasts to stay in place and bears raised orange-ish fruiting bodies along the lobe margins. Simple, yes. Simply amazing. Oh YES.

–Common Macrolichens of the Pacific Northwest, Oregon State University (
–US Dept. of Agriculture, NRCS (
–Wikipedia, Peltigera (
–USDI, Bureau of Land Management, Survey and Manage (
–The New Garden Encyclopedia, Wise & Company
–Royalty free images from