hen you pack your life onto the back of a bicycle, the world opens up to you, or so I have found. This holiday weekend, my friend Colin and I biked to Little Falls and back. On the way home we spontaneously decided to poke our heads into an enormous county park north of Sartell on the Mississippi River that I did not know existed. Inside the park, a very friendly grounds crew member named John, quickly took us under his wing for a special sight seeing tour. Near the disc golf course under some pine trees, he stopped and asked us to look at the ground, and to tell him when we ‘saw it’. At our feet was a large patch of tiny lichen with bright red fruiting bodies, that John told us was called British Red Cap:
He said they aren’t very visible on sunny days, and the very gray day that was Monday was perfect for viewing them. Back home I looked them up and found that Cladonia cristatella as a lichen, is actually a “dual organism,” a mutualistic association between a fungus (the mycobiont) and an alga or cyanobacterium (the photobiont). Usually neither can survive on its own. In theory, the fungus receives sugars from the photosynthetic activities of the alga, while the alga receives some minerals and a safe place to live.
Interestingly, although the fungus requires a specific algal associate to form the lichen, each alga or cyanobacterium species is actually much more promiscuous, forming lichens with many dozens species of fungi. For that reason, the lichen actually takes its name from the name of the fungus. Thus lichen taxonomy is actually fungal taxonomy.
For many decades, the majority of mycologists, sadly, have been ignoring lichens. However, in recent years and the advent of molecular techniques, lichens have rightly taken their place in mycological studies.
Lichens can grow in very inhospitable environments– on rocks, sides and branches of trees, gravestones. However, lichens are very sensitive to air pollution, especially sulfur and nitrogen, and so they are natural indicators of air quality. Lichens grow extremely slowly, usually 1-2 mm per year, and are important in the environment because they break down rocks into soil, and they help to stabilize soil that’s already there.
This page’s information comes from http://botit.botany.wisc.edu/toms_fungi/jul2002.html