The Lichens

What are lichens? They are symbiotic organisms made up from members of as many as three kingdoms: the kingdom fungi, kingdom Protista (algae), and the kingdom Monera, which are the cyanobacteria, or what used to be called blue-green algae. The dominant partners are fungi, which surround and cultivate the algae or cyanobacteria, or sometimes both, and use the byproducts of their photosynthesis as food. The relationship allows the algae and cyanobacteria to live in a much drier environment than they otherwise could, and allows the fungi to live above ground in places that do not have the organic materials that are their usual source of food.

Lichens have been described as “small ecosystems”. There are more than 14,000 varieties worldwide, and 3,600 in North America. They cover 8% of the earth’s surface (Purvis, 2000), and exist everywhere but the deep ocean. Although they can produce an array of biochemicals to enable them to colonize and survive on inhospitable surfaces, they are extremely vulnerable to air pollution, and scientists use lichens to monitor air quality. It is estimated that 50% of lichens have antibiotic properties. Lichens are used in Chinese, homeopathic and Ayurvedic medicine. In Himalayan India, thousands of tons of lichens are harvested annually to produce the dye used in Mendi, the traditional hand painting at Indian weddings.

A close inspection of rocks and deciduous tree trunks will reveal many different types of lichens, some of them often misidentified asmold or moss. Two types of lichens that are easily identified on the Arboretum forest floor are British Soldiers, Cladonia cristatella , with their bright red caps, and mushroom lichens, Omphalina umbellifera, which look like tiny mushrooms on skinny stalks.

Lichens may not be the most exciting guests at the party. They’re quiet, dress in muted colors, can’t tolerate smoke, have weird diets, and are sexually ambivalent. But they do add a subtle layer to the life of the forest and field, adding character to rocks and trees, their variety and size proclaiming the health of the air and water in our Catskill landscape.