Explanation

Lichen is a symbiotic association of algae and fungi. According to a view for the nature of association in lichen, the relationship between fungus and the algal partner, is an example of symbiosis but fungus in his partnership has an important role. The algal partner lives as a subordinate partner the association between the two partners is thus, described as beneficial salavary for the alga. A term helotism is used for this kind of association.