Description: Small crusty or scale-like growths found on rocks. Lichen can be nearly any color: white, black, orange, red, green, gray, yellow, etc.

Habitat: Lichen are often found growing on rocks in the desert. Generally they are found growing on the north side of rocks. It is said that undisturbed habitats are especially rich in lichens. By the way, lichens, in their many variant forms, are found practically everywhere, from the desert to the artic to the dense forest.

Comments: There are many types of lichen. They are generally categorized as dust, crust, scale, leaf, club, shrub, or hair. The ones shown on this page would fall into either the crust or scale categories.

Lichen is a dual organism composed of a fungus and a colony of either green algae or cyanobacteria existing together in a symbiotic relationship. The green algae or cyanobacteria is the photosynthetic partner in the relationship.

Interesting fact: Specimens of lichen estimated to be as much as 4000 years old have been located.


  • Alden and Heath, National Audubon Society Field Guide to California, Knopf, 1998.
  • Kershaw, MacKinnon, Pojar, Plants of the Rocky Mountains, Lone Pine Publishing, 1998.
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