Northwest Lichenologists

Lichens - Osher Lifelong Learning Institute

15 Oct 2022 1:24 PM | Katherine Glew

Lichens in Puget Sound

Always wondered about what lichens are and why they are found on your trees and Rhododendrons?  Lichens are harmless to your plants and add aesthetic value to trees and shrubs. We can actually use them as indicators of air pollution! Lichens are friendly and interesting organisms that love to grow on trees, shrubs, picnic tables, benches, and rocks.  

Lichens are major components of most terrestrial ecosystems, and a few can be found in aquatic environments.  They are symbiotic organisms made up of a fungus and a photobiont (green algae and/or blue green bacteria). They indicate levels of air quality and forest health, contributing to nitrogen and carbon fixation. 

This course will provide an opportunity to learn the most frequently found
lichens in our urban Puget Sound area and major taxonomic groups.  In addition, an overview of how they have been used by people, both economically and for monitoring pollution, will be offered. You will learn about common lichens found in an urban environment and take home a user-friendly chart that lists lichens found in your neighborhood.

The class meets on Saturday, October 15th & 22nd at the UW Seattle Campus. 
There will be one field trip on Tuesday, October 18 (10:00 AM - 12:00 PM) at the Washington Park Arboretum.

Registration:  Lichens (

Fee: $40

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