Foliose

Lichen: Definition
Lichens are a small group of curious plants. Lichen represents the permanent association between Algae and Fungi. This association is a symbiotic association, it means both the partners are mutually benefitted. The Algal partner which is associated with the body of the lichen is called Phycobiont and the fungal partner is called Mycobiont.
The Algal partner forms only 1-5% of lichen body (lichen thallus). In the phycobiont, the members which are present belong to Chlorophyceae and BGA. The phycobiont forms food for the fungi and performs photosynthesis. If the phycobiont is GBA, then it is involved in nitrogen fixation such type of lichen which can perform Nitrogen fixation is known as Azotodesmic.
In the mycobiont, the fungal partner belongs to Ascomycetes but in a few cases, it can also be a member of Basidiomycetes. Mycobiont protects algae. It will form a protective covering along phycobiont (Algal partner). Along with that it also helps in the attachment of lichen to a different surface. It also assists with water and mineral absorption.