Nature Notebook – Lookin’ for Lichen

The display of autumn leaves and spring flowers are spectacular and awe-inspiring.  Lichens are equally inspirational but their display is a bit more subtle…so subtle that most people never notice them.  They are found in most terrestrial habitats: from deserts to Antarctica, atop cooled lava and even on sterile soil.

Lichens are actually two organisms, a green alga or cyanobacterium and a fungus, living together as one.  Scientists are still debating whether this is a mutualistic partnership or a parasitic relationship on the part of the fungus.  The algal partner is able to photosynthesize food for both parts when the fungus absorbs enough water.  The fungus also provides a protective shield for the alga.

If you want to view a lichen, you simply have to look carefully on soil, rocks, tree trunks, or old untreated wood.  Each lichen is usually small but many may be growing side by side.  The individual lichens are slow growing, some only grow one centimeter over the span of one hundred years!

Lichens can be seen in many places.  However, you will not see them where the air is polluted or acid rain is common.  The lichen is unable to metabolize the toxins and dies.  They are so sensitive that air scientists use their presence, or lack of, as one determinant of air quality.

So, grab a hand lens and go lookin’ for lichens!