by Judy Wyper
Algae and fungus join together to form lichens.
Our woods are covered with a variety of them. Briefly, there are three major types: crustose (grow low to the surface), foliose (leaf-like or have distinct lobes), and fruticose (bushy growth structure).
Lichens contribute to a healthy ecosystem, fixing nitrogen from the air, cycling nutrients, contributing to the food web of the forest. They are sensitive to air pollution, and die off in poor conditions of mercury emissions or acid rain. Lichens are therefore good indicators of air quality. Our forests are filled with lichens. After a wind, the forest floor is strewn with bits of foliose and fruticose lichens ripped from their moorings. Lichens are often found growing closely with mosses.
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