More specifically, their relationship is called mutualistic , because both benefit from the relationship. The fungus holds water to keep the alga moist, digests rock and makes the minerals available for both to use, and generally serves as protection for the alga. The alga produces organic food for both by the process of photosynthesis. The scientific names for lichens apply to each type of lichen there are not separate names for the fungus and alga in a lichen. Lichens are often a grayish-green color, but may be brightly colored.
Lichens are good at colonizing bare rock and starting to break it down into soil.
Because lichens depend on rainwater as a source of moisture and air as a source of CO 2 from which to make sugar, they are extremely sensitive to pollution and are among the first to die. Thus, these fungi are indicator species for poor air quality. All rights reserved. This page has been accessed times since 15 Mar 2001.