Lichen is an unconventional form of symbiotic association between a fungus and an algae or a cyanobacteria. It is considered a composite organism because it is a form of joint venture or cooperation between two or more organisms. One partner gives the necessary nutrients and the other partner gives the needed energy.

Lichen is commonly found in constantly moist and humid regions, and can be found on rocks, trees, and soils. It range in color which can be white, gray, green, yellow, brown, pink, or black. Lichen often grows in colonies, forming an intricate web of circles, blotches, or filaments.

Lichen is a beneficial organism to the environment and is often used for pollution indices, since many species are sensitive to levels of S02,NH3, and 02 in the air. Lichen helps fertilize the soil by trapping nitrogen from the atmosphere.

Types of Lichen

There are three basic types of lichens, distinguished by the type of fungal partner they contain:

  • Ascomycota - These are the most diverse type of lichen and contain a fungal partner from an ascomycete class like sac fungi.
  • Basidiomycota - These lichens contain fungal partners from Basidiomycete mushroom fungi.
  • Zygomycota - This type of lichen contains a zygomycete fungal partner.

Uses of Lichens

Lichens have many uses both in the scientific and commercial worlds. The dyes found in lichens are used to produce various shades of greens, blues, and purples. Other lichens can be used in treatments for stomach problems, cancer, and even in nutrition.

  • Lichen is used as an indicator of air quality since they absorb nitrous oxides and sulfur dioxide from the air, and react to other pollutants.
  • It is used to produce perfumes and as a food coloring in sauces and seasonings.
  • It is used in some natural medicines to treat various conditions like stomach problems, cancer, and other health issues.


Lichen is a fascinating organism that plays a vital role in the environment. It not only provides us with a way to detect air pollution, but also has a variety of uses in the medical and commercial world. With so many uses, it is clear to see why lichen is such a valuable and important organism.