NATURE NOTE – Number 71 June 28, 2023
As I have discussed before, we often overlook things that are a common part of nature (See NATURE NOTE# 64). As a scout leader, you can easily point these out as long as you know a little about the item. So let’s help you know something about an interesting part of nature that you will certainly encounter as your scouts get out and about this summer or probably find in their own backyard.
Our Current Topic: Lichen
First, what is lichen? Lichen is a very interesting plant that is a combination of algae and fungus that can be explained in detail only by going into more botany than most scouts (and adults) will want to hear. So for this NATURE NOTE, let’s keep it simple. We all have seen lichen on rocks, old logs, trees, fences, tombstones, brick homes, and most any other surface. We might take it to be a moss, with which it may associate in a moist site, but it is not bright green or moist or soft like moss, but an assortment of grey, yellowish, greenish, brownish or even red plant-like material that is dry to the touch and often scaly, often leaf-like, that sticks solidly to a surface. It does not have leaves, stems, roots, vessels or veins. Based on appearance, there are 3 types of lichens. The names of these types are not important, but the description of each may help you find different examples.
- Foliose lichens: flat, leaf-like, two sides, often with scalloped edges, lumps and ridges.
- Fruticose lichen: stands upright, maybe on a stalk with a cup-like top, or hair-like, or flat stalks.
- Crustose lichen: crusts, often colorful, hard pressed against the substrate, almost like a stain.
As to locations, it’s everywhere. One of its characteristics is its ability to grow in the harshest conditions around the world, from the artic (reindeer and caribou feed on it) to the barren desert. This is possible because of its simple structure, requiring only some sunlight and a little moisture. By definition, lichen is a unique mutualistic life form that has most characteristics of a fungus, which provides the structure or “bones” of the lichen, as well as a source to hold moisture, and the algae which, like any green plant, uses sunlight and moisture to make “food” for the plant by photosynthesis. There are many species of fungi and many species of alga that can combine to make an almost endless number of lichen species. One lichen species may have one species of fungus and two species of alga as its makeup, while another may have one species of algae combined with two species of fungi. Many species remain unnamed, or even discovered.
The host, such as rock or tree stump, provides nothing for the lichen except as a place to anchor. It is not a symbiotic relationship. No harm is caused by the lichen to a growing plant as it does not penetrate the plant cells. However, the lichen does produce an acid that can slowly eat into a rock host and create tiny holes in that rock that will allow for better anchorage, and create tiny grains of sand or other minerals from the rock that will blow away and help feed various minerals back into the soil. The mineral content will in part be reflected in the lichen color. In addition, over time, the lichen may well act as a net to stop small wind-born seeds that will germinate and start a new plant near the lichen.
Lichen reproduction is somewhat strange. It can occur in a couple of ways. If a piece of lichen breaks off and is transported by wind to another location, that small piece can continue to grow as lichen. It is not a new lichen – that one little piece just “moved”. As long as that piece contains a cell of algae and a cell of the fungus, it can continue as lichen. The fungus part of lichen can produce spores, like mushrooms, but the windborne spore will not produce lichen. It will only produce a new fungus of the same species that generated the spore. If, by some chance, an algae cell and a fungus cell find each other in a new suitable site, a new lichen may form.
In addition to providing food for some wildlife, humans have used lichen for dyes and medicines over the ages. While usually harmless to humans, there are examples of skin rashes, and some suspected cases of illness when ingested. Hint: don’t eat lichen.
Many scouts have never noticed lichen or heard about its strange makeup. Here is a chance for you to show it to them and explain a little about it. Some scouts might be interested in something new that has never been explained to them before. Maybe use your cell phone to capture photos of different types. You may point out that its simplicity is what gives it the power to survive in a habitat that would exclude many other plants. Sometimes all you can do is expose scouts to a part of nature and let them go from there. Who knows where it might lead. You will never run out of new things to explore in nature. Good luck with lichen looking!
As always, thank you for reading NATURE NOTES and being interested in nature.
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