We notice that a lichen is built by a fungus and an alga or cyanobacterium.
Some children found a piece of wood with some kind of plants growing on it, what are they?
They are lichens. There are more than 17,000 species of lichen worldwide. They grow on any surface such as wood, rock or soil. Lichens have their favourite places to grow, they can absorb water through any part of their structure and have no roots. And they also obtain energy from the sun to make their own nutrients.
Lichens have colonised every continent, including Antartica. Most of them are edible, they have amushroomy flavor, but there are some poisonous. They are habitat for many animals, and provide nesting materials for birds. They also protect trees and rocks from extreme elements as rain, wind and snow. Students observe the pieces of wood covered with lichens using different kinds of magnifying glasses.