Tag Archives: symbiosis

Lichen or not here we go!



As promised I said I would bring more diversity to my posts so here we go. I love walking in the woods and being surrounded by trees. To me it is a very relaxing thing. While some people may be skittish about being in nature I am not at all. The reason for that is simple there is NOTHING out there that will harm you, the danger comes from other PEOPLE.

One of the wonderful creations of God that no doubt you have seen on trees in your very own neighborhood and just didn’t know what it was is something called Lichen: How do I describe what Lichen is as it is not a plant or an animal but is a fungus that has a special relationship with a type of alga, or cyanobacteria (dark-blue bacteria) these two pretty much combine forces for mutual benefit.

The algal or cyanobacterial cells are photosynthetic, and as in plants they reduce atmospheric carbon dioxide into organic carbon sugars to feed both symbionts. Both partners gain water and mineral nutrients mainly from the atmosphere, through rain and dust. The fungal partner protects the alga by retaining water, serving as a larger capture area for mineral nutrients and, in some cases, provides minerals obtained from the substrate. If a cyanobacterium is present, as a primary partner or another symbiont in addition to green alga as in certain tripartite lichens, they can fix atmospheric nitrogen, complementing the activities of the green alga.

There is so much varieties with the species of lichen and one specific type of fungus could work together with often a number of alga species to be a different type of lichen so the colors are quite interesting.

Lichen are divided into several groups depending on what they look like, if they look like leaves they are known as foliose (think of foliage) and crustose which looks as is probably quite obvious like a crust. The foliose types are often found on trees and can be specific to particular species of tree. And the crustose can be found on walls or rocks.

Here is a  picture of lichen in Washington DC. Is it foliose or crustose?

You may very well have lichen on a tree in your yard or in front of your house. They can be most easily seen after it rains or when the air is otherwise moist.

and pictures of lichen are below (these are pictures I took just last week).

I will add more pictures of local lichens soon so stay posted.


As promised here are some more pics they are quite dry but they are quite alive nonetheless.

Lichen on a log