Microorganisms Taxonomy Habitat
Fungi Viruses Bacteria
What is lichen?
There are many different kinds of lichen, but all forms of lichen are made up of more than one microorganism. These groups of organisms are made up of fungus and cyanobacteria and live together in a relationship that is called symbiotic. Petula is one form of lichen and it is an unusual type. They are unusual because the one kind of microbe called hyphae connects the rest of the types of microbes together to make this kind of lichen. Another interesting fact about lichens is that they can live through long dry spells and spring back to life and grow when it rains or the snow melts.
The Microbe World - photograph   The Microbe World - photograph
Hyphae forms into strands that hold the rest of the microorganism in the lichen together in a clump. . Yellow lobes called squamules are held together by microbes called hyphae
 
How is lichen identified?

The main structure on lichen is the body, called the thallus. Lichens are put into four groups according to the shape of the thallus.

Foliose lichens flat, leaf-like structure The Microbial World - photograph
Fruticose lichens bushy structure The Microbial World - photograph
Squamulose lichens tiny, scale-like squamules The Microbial World - photograph
Crustose lichens flat crust on or below rocks or under the bark of a tree The Microbial World - photograph

 

 
The most common cyanobacterium in lichen is Microcoleus vaginatus . It looks like fringe on the surface of lichen. There are from 13,500 to 17,000 species of lichens that live in all sorts of environments, polor to tropic regions. They grow on tree bark, leaves, rocks, the ground, cooled lava, or any other surface that provides enough moisture for the fungus to grow.
The Microbial World - photograph The Microbial World - photograph
How does lichen reproduce?
Lichen reproduce by a process called vegetative propagation. That means that the brittle thallus of the lichen can break off easily and be moved by water, by travelling on animal fur, or by wind to a new spot and begin growing a new colony of lichen. Another way that lichen can reproduce is from a special powdery mix of photosynthetic cells coated with fungal hyphae called Soredia. The wind can easily blow the Soredia powder to a spot where it can grow. A third way that lichen reproduce is to produce spores at the tip of the thallus. These spores can meet and begin a new colony of lichen.
 
The Microbial World - photograph
You can see that smaller colonies of lichen have broken off and grow away from the main lichen.
What does lichen do?
Where ever lichen grows its job is to help make new soil and make the soil that is already there richer with nutrients. In some barren areas, lichen provide a source of food for deer and other grazing animals. Some lichens are parasites and grow on or in the leaves of some tropical crop plants that are bought and sold: coffee, cacao (chocolate) and rubber. Lichens damage these plants and scientists are trying to find ways to keep these lichens from growing on them.
 
 
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