Lichens are plants that can grow in the most inhospitable place and in the most adverse habitat, such as on a bare rock. Their secret is that they are two plants, a fungus and an alga, that are joined in a marriage where each contributes to their combined success. The alga produces the food for itself and the fungus, and the fungus provides the structure and collects water for them both.
With no roots, lichens get their water and nutrients from the air. They can survive extremes of heat, cold and drought and can grow in the harshest places where other plants cannot establish themselves.
Lichens can be found in the Arctic tundra, the hot deserts, along rugged coasts and on the side of stone monuments. They can live in the frigid rarefied atmosphere at elevations over 6,000 meters.
The word “lichen” means solitude which seems fitting for a plant that can live in barren locations where it is impossible for other plants to get a foothold.
It is estimated that lichens are the dominant vegetation on 8 percent of the earth’s surface. There are about 3,600 different species of lichens in North America.
One lichen, a rock tripe, is edible if cooked properly, according to naturalist Ernest Thompson Seton. He wrote in “Birch Bark Roll,” “The taste is like tapioca with a slight flavoring of licorice.” George Washington’s Continental Army is said to have consumed rock tripe to survive the murderous winter of 1777 at Valley Forge.
Two species of lichens were sealed in a capsule and launched on a Russian rocket on May 31, 2005. The capsules were opened in orbit and the lichens were exposed to the widely fluctuating temperatures and cosmic radiation of space. Back on Earth, after 15 days in orbit, the lichens showed no ill effects.
Because lichens draw moisture and minerals from the atmosphere, they act as filters to the air we breathe. Despite their ability to survive in the most extreme environments on earth, they cannot tolerate pollution in the air and will not grow when accumulating airborne pollutants. If you live where there are plenty of lichens, it probably means you have excellent air quality.
The fungi and the algae are a good team, doing what they do best in a mutual, symbiotic relationship. It is a marriage that survives, even on the rocks.
