Desert Lichen Bright Green Color $3.99 per ounce

The uniqueness of lichens

What is so unique about lichens is the huge variety of colors and shapes. Lichens grow as inconspicuous crusts, broad lobes and filigreeing beards. They can be orange, deep, pale or bright yellow. They may be green with a yellow tinge, deep green or olive. Some are gray, pale or dark brown, others are mauve, ivory and even black. As colorful blotches they cover almost all of natures' canvas: They grow on the bark of a tree, on dead wood, on bare rock or barren soil.

Lichens are found in the tropical rainforest and the arctic cold deserts. They grow in temperate forests and in the coniferous forest of the Taiga. Thick carpets of lichens cover the arctic tundra and thin crusts embrace the desert soil.

What is a lichen?

First things first -- lichens are NOT plants. Lichens appear as an entire organism but are actually composed of two very different partners. One partner is a fungus, also called the mycobiont. Modern classification regards the fungi as an entirely separate kingdom quite unlike plants and probably more closely related to animals. But lichens are not just fungi. The other partner in this relationship is called the photobiont. Photobionts may be green algae or they may be blue-green bacteria.

The lichen fungus usually provides structure and appearance of the whole lichen. Fungi are organisms which grow as fine filamentous threads called hyphae. In a lichen these hyphae are densely woven around photobiont cells to form the lichen thallus. The thallus is thus the "body" of a lichen composed of a mycobiont with a population of photobiont cells.

Where do lichens grow?

Lichens do not have roots and do not need to tap continuous reservoirs of water like most higher plants, thus they can grow in locations impossible for most plants, such as bare rock, sterile soil or sand, and various artificial structures such as walls, roofs and monuments. Many lichens also grow as epiphytes (epi- on the surface, phyte- plant) on other plants, particularly on the trunks and branches of trees. When growing on other plants, lichens are not parasites; they do not consume any part of the plant nor poison it.

Some ground-dwelling lichens, such as members of the subgenus Cladina (reindeer lichens), however, produce chemicals which leach into the soil and inhibit the germination of plant seeds and growth of young plants. Stability of their substrate is a major factor of lichen habitats. Most lichens grow on stable rock surfaces or the bark of old trees, but many others grow on soil and sand. In these latter cases, lichens are often an important part of soil stabilization; indeed, in some desert ecosystems, vascular (higher) plant seeds cannot become established except in places where lichen crusts stabilize the sand and help retain water.