Getting a Good Start Looking for Lichens

Looking for Lichens
Lichens are a pioneer species - geology meets botany. Lichens, over time, break down rocks and create soil or organic material and take nitrogen out of the atmosphere. Lichens are everywhere, from sea level to mountains, with over 19,000 different species, making up 8% of the world's biomass, so it's easy to see why it's a challenge to identify them. The more you learn about lichens, the more mysterious they become.
If you want to become a lichen-scout, here is some basic information to get you started. Look and learn. Get very close, observe, then read different books/reports on the structure of lichen. Repeat.
In its simplest form, a lichen is a fungi that has an alga living inside, in a mutually beneficial arrangement (symbiosis). The fungi provides the space to live (structure) and the alga photosynthesize the food for both. Lichens are not dependent on the host or substrate for nourishment. Lichens do not harm trees, but older trees may be covered in lichen while also at the end of their lifespan. Truth be told, the fungi and the algae can live independently, but together they form a lichenized fungi called a lichen.
First, identify lichens by shape or profile. These three growth forms can be subdivided further, but for now, this will suffice.
Crustose lichen - is embedded into the substrate it lives upon. It might look like spray paint or raised texture, but you cannot separate the lichen from the substrate without damage to either.
Foliose lichen - is firmly attached to the substrate, but you can lift an edge and look at a bit of the underside of the lichen. Notice the clues on the underside of lichen too, different textures and colors than the upper side.
Fruticose lichen - is hanging on by a central stem that may be obscured from the top view. It resembles a tiny shrub.
More often, lichens have additional components besides a single variety of fungi and algae, that create a more complex organism and add to the difficulty in reaching the species level of identification. It can contain additional fungi, yeast, or cyanobacteria. Lichen genus may be determined through careful observation, but frequently chemical spot-tests are needed to determine the species.
80% of lichen structure is not visible to the naked eye, so a jeweler's loupe or hand lens is necessary in the field. A lichen viewed with magnification reveals important structures that will assist you in lichen identification.You can even use your smartphone and shoot the image through the loupe for extended magnification.
Up close to the lichen specimen you can see, none, a few or many flat round disc-like reproductive structures called Apothecia. The shape, size and abundance of these ‘fruiting cups’ will be clues to the species identification of the genus and species you are observing.
No Apothecia? Look to the outer edge of the lichen structure for the presence of isidia or soridia, reproductive structures.
Where you find the lichen growing is another clue to genus and species. Where is referred to as the substrate. On a rock? On the ground? On a tree or bark chip? The substrate is not the same as a host, because the lichen is getting its nourishment from the sugars produced by the algae. The general habitat is also important, forest, wetland, desert and will determine the humidity that creates an environment needed for that specific lichen to thrive.
The introduction to most lichen books (some listed below) will have this information and more. Read every introduction so the information becomes clear and the jargon is second nature. Continue to search for lichens, photograph them and enjoy them as you learn. By observing and scouting for lichen you will begin to have a deeper appreciation for these slow-growing, beautiful organisms.
Lichen-scout, as you walk, crawl, and lay on the ground that is our home, Minnesota, be respectful to all Creation - especially slow-growing lichen. First Nation leader, Dr. Leroy Littlebear says that “The land is a sacred trust from the Creator. The land is the giver of life like a mother.” Some lichens grow only 0.5mm per year.- a sharp pencil point is 1mm. A lichen as big as your thumbnail could be decades old. Lichens are a wonderful way to explore Minnesota.
Basic Vocabulary
Lichen
Fungus
Algae
Substrate
Habitat
Crustose
Foliose
Fruticose
Apothecia
Isidia
Soridia
Basic Good Videos
Overview:
https://www.youtube.com/watch?v=crAXLSZZzXw
Lichen Structures:
https://www.youtube.com/watch?v=qJa1OlJ3vRs&t=760s
Good background information:
https://www.youtube.com/watch?v=lh3https://www.youtube.com/watch?v=YqHG7SOmtY4&t=889sxFOw62aU
Types of lichen growth forms:
https://www.youtube.com/watch?v=Z2haTr0j4hk
Further Reading:
The Secret World of Lichens: A Young Naturalist's Guide
A beginner naturalist's guide to the wonderful world of lichens.
Written by lichenologist Troy McMullin
Urban Lichens: A Field Guide for Northeastern North America
Jessica L Allen & James C Lendemer
Lichens of the North Woods A Field Guide to 111 Northern Lichens
Joe Walewski
The Lichen Museum
An interdisciplinary look at the world of lichens.
Laurie A. Palmer
Common Lichens of Wisconsin
University of Wisconsin Herbarium
https://herbarium.wisc.edu/wp-content/uploads/sites/205/2017/10/lichens-of-wi-web-20170515.pdf
Join:
British Lichen Society
Lesson plans and lichen walks
https://britishlichensociety.org.uk/

World-wide Lichen Study
https://microbeinstitute.org/lichen-adventure
Cheers! Zan

Posted on April 30, 2023 01:57 PM by zancan