| Lichens | |
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Several different kinds of lichen decorate the shady side of this granite outcrop, each one adapted to a special microclimate. Lichens ("likens") are a hardy combination of a fungus and an algae species. The fungus holds fast to the stone, breaking it down and absorbing nutrients from its minerals, and shelters the alga. The alga creates food from sunlight and water, nourishing the fungus. The nightly moisture of the desert dew and frost is enough to nurture lichens where nothing else will grow.
Lichens are an important agent of weathering, helping to turn solid rock into loose particles. Here's a page with more about lichens and the stones they live on.
(c) Copyright 2002 Andrew Alden, licensed to About.com, Inc.
