Lichens as pollution monitors

A description of lichens including their structure, reproduction, growth, physiology, and ecology is presented. A discussion of their relationship to environmental pollution and their value in monitoring is included. Suflur dioxide's effect on photosynthesis and respiration, vitality, substrate preference and mechanisms of resistance is described. Other pollutants, such as smoke, fluorides, car fumes, metals, radionuclides, and agricultural chemicals are also considered. Because of their sensitivity to change, lichens are a particularly good indicator organism to changes in the chemical environment. (DMC)