What are lichen, and what do they do? Well…exactly what they are is not set in stone, and our understanding is still developing with technology and research. Scientists used to believe that they are an alga and a fungus working together (symbiosis). However, with current understanding, it may be more accurate to say they are a whole micro-federation of ecology with key players in alga and fungi. This is where scientists are still trying to unravel the intricacies of their varied component species (also including bacteria) and how they work together.

What do they do? Now, this is a very wide range of ideas to talk about, so let’s focus on nature without going into too much detail. Lichens are believed to be one of the first land colonizers. The fungi give protection and nutrients to the alga (photobiont), which makes photosynthates (food) that it shares. The fungi (mycobiont) attach to many surfaces such as rocks, for example, and can use an enzyme to minutely erode those surfaces to free up nutrients. This may sound similar to those familiar with soil morphology, considering rock to be the parent material for future soils.

Many like to consider lichens as extremophiles, because they are organisms found in some of the harshest conditions on earth. However, lichens are also found in milder conditions like temperate forests. Some can be indicators of air quality by their relative presence or absence. In extreme locations, they can be one of the few scarce sources of food for animals, as well as pioneers in disturbed or newly formed lands with barren rocks. The newly-created free nutrients and the holding eroded face of rock make a nice place for mosses to colonize, which then builds more soil for more plants to grow. But you don’t need to travel to a volcanic island or arctic tundra to see this; you can see it happening right in your backyard. Next time you’re out and about, look for a rock with lichen in the process of going to moss, then to ferns or vines, and maybe some woody perennials springing up from this process.

If you want to get a little more detail and really see them, a small inexpensive field microscope that fits in your pockets can show you so many of the different shapes and structures of the lichen reminiscent of fascinating geological formations and much more. To the naked eye, lichen are not all just crusts (crustose). Some look like a hap-hazardous doily dropped and ruffled. Others are like coral with ridges, plates, and holes (foliose), or even a fine powder. One of my favorite, reindeer lichen, which is like a miniature bramble bush (fruticose). So, stop and… well, don’t smell the lichen, but take a look and appreciate them for what they are.