The Daily Bucket: There's a lot to Like in lichens.

Pacific Northwest

Whatcom County, WA

There are many facets of nature that are right in front of us but are too often overlooked as I tried to demonstrate with my previous Bucket on mosses. It is important, I believe to learn what we are looking at so as to enjoy nature from the tiny organisms to the cosmos. Here we look at lichens.

Lichens are an odd form of life.  I was going  to call them odd critters but they are not animals and therefore not critters. They are not plants either nor are they really fungi per se, although they get classified along with fungi. They are kind of both.  As hybrid organisms, lichens are classified taxonomically in the Fungus Kingdom since its base or its main structure is largely made up of fungal material. Within the fungal structure are also green algae cells and sometimes Cynobacteria. Within this main body (thallus) there are fungal hyphe intertwining among the green algae cells as shown below. Thus, this organism has components from the fungal kingdom and the plant kingdom (algae), and sometimes from the monera kingdom (cynobacteria). So this is an organism whose components can come from three different kingdoms of life. I say WOW, that’s a super organism!

So why would such different life forms team up to form a lichen? I certainly can’t answer the why question but it is clear that they symbiotically contribute something to one another’s existence. As noted above one of the fungal contributions is the physical structure. But since fungi can not do photosynthesis they rely on the algae or the cynobacteria to provide them with the necessary nutritional products of photosynthesis such as carbohydrates. The main fungal body can convey necessary water and nutrients to its guests through its mycelial and hyphae systems. In  addition lichen can absorb water directly into its body from rain or just from water vapor, although they are not good at retaining it. They tend to thrive in wet and foggy environments. When the moisture is absent, they dehydrate and go dormant until water returns. This process is known as "poikilohydry"

  The result of this admixture of life forms is not a monster but a very interesting multi-kingdom organism.

Classification of Lichen types:

Although lichens are living organisms, they lack formal status as a taxon of living organisms. Rather, the vast majority (98%) are taxonomically classified under the Ascomyota phylum of the fungal kingdom. Further taxonomic classification is based on the more specific type of fungus that provides its mycelial structure.  

Most lichens can be described as falling into one of several structural forms although these forms do not all fall neatly into our constructed categories. They do have an “other” category called: “unstructured” which is typically just a agglomeration of algal and fungal cells that form a jelly-like mass. 

Following are a few examples of common lichens that I have found in my yard and on my various forays into the woods of our region. You might see these on your walks as well. They are arranged by the structural category that best describes their physical features rather than their taxonomic groupings. Although none of these lichens are unique to our area, they are among our most common specimens in the Pacific Northwest.  

Caveat: Many of these lichens are not easy to identify, particularly at the species level - just ask Seek. Even the lichenologists continue arguing. We (me, Seek, iNaturalist, and numerous sites on google) have tried to do what we can. If anyone has any questions or quibbles about a genus or species, please chime in. I am finding that there are often several right answers but I’ll let the pros duke that out.  We are all here to learn and enjoy nature. 

Foliose  (leaf-like)

Tube Lichen

Crustose (crusty)

Fruticose (Branching, shrub-like)

One of the largest genera in the Fruticose category is Usnea. The species of this group include many that resemble beards and have been given such common names such as “Old man’s Beard,” “Methuselah’s Beard,” “Bristle Beard” and so on. These are found dangling from coniferous tree limbs and can grow up to 20 feet long. They are often mistaken for Spanish Moss which has uniform strands while these have a main branch from which the bristles grow. These are now considered rare in many habitats as they are highly sensitive to airborne pollution.

The next two photos might or might not be separate species of Usnea as various references sources disagree. It is probably safest just to call them beard lichen.

Leprose (powdery)

Mustard powder or Gold Dust lichen (Chrysothrix candelaris) does look like a powdery spray. However, up close it has some more defining features.

Squamulous (scaly)

Uncategorized:

Lichenomphalia umbellifera

L. umbellifera is a relatively rare lichen around the world but is somewhat common in the Pacific northwest. It is one of a few lichens whose fungal component grows an agaric (a mushroom body) with a stem/stipe, cap and gills under the cap. This lichen is taxonomically grouped under the phylum Basidiomycota. It was originally described by Carl Linnaeus in 1753 and has undergone various name changes.

What good do lichens do?

1. Food: I noted above that the Cladonia genus provides food for numerous animals during the cold winter months in the tundra, at high elevations and latitudes of the north. Humans eat it as well when necessary.
2. Soil formation: Lichens secrete acids which assist in breaking down their substrates such as rocks which contributes to soil formation.
3. Nitrogen fixing: Some lichens can extract nitrogen from the atmosphere and transfer it to soils to be available for other organisms. Dog-pelt lichen is one that is a nitrogen fixer. It has little black spots on its leaves that are cynobacteria which take nitrogen from the air and convert it to form soil nutrients. Some species of Peltigera have both cynobacteria and green alga and thus have all three lichen components.
4. Habitats: Lichens provide habitats for small organisms such as insects and invertebrates. Their foliage serves as nest building material for birds, and to line tunnels for burrowing animals.
5. Bio indicators for pollution. Some lichens are highly sensitive to the presence of atmospheric nitrogen such that they are harmed, whereas others are insensitive and are unaffected. Finding a loss of the sensitive species is an indicator of high levels of atmospheric nitrogen or sulfur dioxide. Lungwort is highly sensitive so if you find it, you can assume at least the local nitrogen levels are not too high. 
6. Dyes: Various lichen colors have been used for dying fabrics throughout history.  A lichen found abundantly in the Scottish highlands has been the traditional dye for Harris Tweed. 
7. Lichenometry: Lichens, as slow growing organisms are used by climatologists to gauge the length time a rock has been exposed, based on the size of the body (thallus). For example, sunburst lichen (Xanthoria  and map lichen (Rhizocarpon geographicum) are two that are often so used.  
8. Perfume: oakmoss is a prized lichen in Europe for perfume bases and is dated back to the 16th C. Also, baskets of oak moss have been found in ancient Egyptian tombs.
9. Medicine: Indigenous populations throughout human history and currently use lichens to treat numerous conditions. Currently lichens are still used in traditional Chinese medicine and among other herbalists although the medical research is not clear on effectiveness. Usnea (the beard lichens) is a mainstay here for its usnic acid thought to be the basis of many treatment effects. Antibiotic creams are made from Cladonia (reindeer moss, pixie cup)

I am sure that there are lichens around your area. Please share some of your finds with us and be sure tell us where they came from.