< Previous | Contents | Next >
A lichen is a peculiar combination of an alga and a fungus-the two live deriving mutual benefit. They are group of greyish green plants which grow on rocks, tree-trunks, dead wood, etc.
The algae manufactures food which becomes available to the fungus, and the absorbs and retains water and thus keeps the algal cells moist. A example of symbiosis.
They are most common in wetlands, rare in rivers and streams and are not found in ground water.