Lichen

 

A stone wall on which lichen is thriving. Where you have lichen such as this the air contains little or no pollution.

© Gerry Costello

Lichen Is A Composite Organism

After observing the stone walls of the area and how they were built we take a closer look at the stones themselves. Looking at the stones one observes that the surface contains white and orange coloured patches. these are natural life forms known as Lichen and there is plenty of it to be seen in this area.  A lichen is a composite organism that emerges from algae or cyanobacteria (or both) living among filaments of a fungus in a mutually beneficial (symbiotic) relationship. The whole combined life form has properties that are very different to properties of its component organisms. Lichens come in many colours, sizes, and forms. The properties are sometimes plant-like, but lichens are not plants. Lichens may grow like a tiny, leafless, branching shrub (fruticose), like it has leaves (foliose), like a crust of paint on a surface (crustose), or have other growth forms. A macro lichen is a lichen that is either bush-like or leafy. A microlichen is everything else. Here, “macro” and “micro” do not refer to size, but to the growth form.

Names

Common names for lichens may contain the word “moss” (e.g., “Reindeer moss”, “Iceland moss”), and lichens may superficially look like and grow with mosses, but lichens are not related to mosses or any plant. Lichens don’t have roots that absorb water and nutrients like in plants. Instead they produce their own food from sunlight, air, water, and minerals in their environment. They are not parasites on the plants they may grow on, but only use them as a substrate to grow on or in.