Lichen

The term lichen was first given by Theophrastus.

Study of lichen are called Lichenology.

Father of lichenology is Erik Acharius.

Major part of lichen thallus is composed of fungal component.

Like in a distinct group of organisms having two component :-

Algal component called phycobiont.

Fungal component called mycobiont.

algal component of lichen synthesise carbohydrate by photosynthetic and provide nutrition to fungal component and fungal component provides shelter and absorb nutrition and water for its partner lichen as an example of symbiosis.

Economic importance of lichens

• Lichen as a source of dye.
• Litmus is obtained.
• Usnic acid  is important broad spectrum antibiotic.
• Indicator of air pollution.
• Lichen are very sensitive to Sulphur dioxide and die at the higher level of Sulphur dioxide.

Lichen age biological pollution indicator.

Forest fire.

Usnea popular known as old man beard is of inflammable nature it is responsible for forest fire during summer season.

On the basis of their fungal component.

• Ascolichen

Ascolichen fungal partner is the member of ascomycetes.

Most of the lichen are ascolichen.

Basidiolichen.

Fungal partner belongs to Basidiomycetes.

Note

Blue green algae found in lichen are nostoc, scytonema, Anabaena.

Classification on the basis of types of thallus.

Lichens are three types:-

• Crustose lichen

These lichen are flat.

Example Graphis.

• Foliose lichen

 These are attached to the substratum with help of  rhizoid .

• Fruticose lichean.