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Reindeer "Moss"

No science fiction writer or practioner of the controversial new field of genetic engineering would ever think to invent such an unlikely plant as reindeer "moss".

Reindeer moss is not a moss at all. Rather it is one of the world's 15,000 lichens. Before the discovery of the microscope lichens were thought to be mosses, hence the strange names some go by. More strange yet is that a lichen, unlike any other plant, is not a single organism. Instead, a lichen is a combination of two different plants--algae and fungi--growing together in an inseparable relationship called symbiosis.

By virtue of its ability to perform photosynthesis, the algae supplies the lichen with food. The fungus furnishes mechanical structure and the water needed for photosynthesis. This water comes out of the air, so the lichen has no roots and is able to grow on rocks or other objects such as tree bark. The lichen may extract some minerals from whatever it is attached to, otherwise all its needs come from the air. Because lichens take their livelihood from the air instead of the ground, they are terribly sensitive to air pollution, and simply will not grow near cities where pollution is bad.

Because of the ability to avoid using soil as a source of materials for life and the ability to withstand extreme cold and dryness, lichens such as reindeer moss can live in arctic and antarctic locations where other plants cannot. When there is enough moisture in the air and when it is warmer than -10°C (14°F) such lichens show signs of life and growth; otherwise they lie dormant.

Under the worst conditions, it can take 100 years for lichens to regrow after being eaten by arctic and subarctic reindeer, caribou, moose and musk ox. Nevertheless, the lichens are crucial forage for these animals, especially in winter. The slow growth rater of lichens may be a factor that causes the population cycle of Alaskan caribou and raindeer to range from 50 to 100 years.