Lichens

Section through Xanthoria parietina showing the algal layer

Section through Xanthoria parietina showing the algal layer

What is a lichen?

Lichens are fungi with an unusual life style where the fungus combines with algal and/or cyanobacterial partners to form an independent organism that is different from the separate partners.

Only the fungal partner in the lichen reproduces sexually. Germinating spores must combine with the appropriate alga to form another lichen.

Lichens range from small crust-like growths to leaf- or beard-like structures.