Lichens

Lichens are living things you can find on rocks, trees, and even old walls. They are not quite plants and not quite anything else. Each lichen is really two living things joined together. A fungus and an algae live as one body and help each other survive.

A Team That Works

Lichens are made when a fungus and an algae team up. The algae uses sunlight to make food, just like a plant does. The fungus gives the algae a safe home and soaks up water. Together they can live in tough places where neither one could live alone. This kind of partnership is called symbiosis.

Tough and Slow

Lichens can grow in very harsh places. They live on cold mountaintops, hot deserts, and even in Antarctica. They grow very, very slowly, sometimes just 1 millimeter a year. Lichens come in many colors like green, yellow, orange, and gray. They help make soil by slowly breaking down rocks.

Fun Facts

• Some lichens can survive the cold, airless space outside Earth.
• Scientists think some lichens are more than 9,000 years old.
• Reindeer and caribou eat lichens to stay alive in the winter.

Did You Know?

Lichens are so sensitive to dirty air that scientists use them to find out how clean the air is in different places.