Lichens

 

(This 1172nd Buffalo Sunday News column was first published on September 8, 2013.)

 

The British Soldiers Lichen, Cladonia cristatella

 

At 7:00 p.m. this Tuesday Jim Battaglia will speak at the Niagara Frontier Botanical Society meeting in Amherst's Harlem Road Community Center. His topic will be "The Lichens of Western New York." This meeting is free and open to the public and, based on the subject itself as well as the preview Jim gave me, I recommend this talk to you.

Like most of us, I knew virtually nothing about lichens when I met with Jim. I realize now how unfortunate this was as not only are these widespread and attractive life forms that are found all around us but they play interesting roles in our world as well. They are indeed well worth our attention and study.

Lichens are formally classified among the fungi along with mushrooms, truffles, molds and yeasts. All these are life forms that do not carry on photosynthesis, the process that converts light energy, normally from the sun, to chemical energy that powers the organism's activities.

But the lichens differ from other fungi in that they partner with certain types of algae, which carry out the photosynthesis for them. The technical term for this partnership is symbiosis. (Some scientists disagree, believing that this is actually a parasitic relationship with the fungal part of the lichen drawing its power from the algae without an adequate return.)

Whatever the nature of the relationship, it is important to both. When separated, the fungal and algae parts of the lichen are unable to function.

So successful are the lichens that they make up about one-fifth of all fungi. And they are found everywhere: from extreme environments like the arctic tundra and the hottest of deserts. There may be a dozen or more species in your yard and possibly even a few microscopic lichens growing on your body.

Remarkably, they have also been shown to be able to survive in space. In 2005 a rocket carried two lichen species into orbit, where they were exposed for two weeks to the temperature extremes, radiation and vacuum above our earth's atmosphere. They came through the experiment and returned to earth unharmed.

Jim pointed out that, unlike most fungi that take nutrients from the substrate on which they grow, lichens draw moisture, carbon dioxide and other nutrients necessary to their survival, growth and reproduction from the air around them.


Okay, that is some background about lichens. What do they look like? To show me, Jim took me on a field trip around his yard in Williamsville. We hardly got out his front door when we almost stepped on a lichen adhering to the cement doorstep. And about ten feet further took us to a large silver maple whose bark supported three species.

Although most of the ones we found that afternoon had spread out into patches of one to six inches, their individual parts were all tiny, the largest about a quarter-inch in size. Jim had me look at them with a hand lens to pick out their characteristics.

Here are the ones we found on that maple:

Shield or net-marked lichen, Parmelia sulcata. This species is gray with quarter-inch lobes arrayed against the tree bark. They have the appearance of metal beaten flat

Rosette lichen, Physcia millegrana. The gray of this lichen had a slight greenish cast. It appeared to me much like coral growth with tiny mushroom-like buttons scattered among the lobes.

Melanelixia subaurifera. A brown lichen with leathery lobes.

On another tree, Jim showed me a small patch of bright gold Candelaria concolor. "If you drive down Bidwell Parkway and look at the elms," he told me, "you will see their bark covered with this attractive lichen."

Examined closely, I found each of these intricate lichen colonies very attractive.

The other species we saw on this tour were similarly flattened against tree bark, but lichens take many other forms as well. One of those, Cladonia cristatella, is called British soldiers because of the little red topknot at the end of many of its arms. Lichens like them serve as food for many animals.

Individual lichen species also serve as human food, dye sources, air pollution indicators and even medicines.-- Gerry Rising