<P> A particular fungus species and algal species are not necessarily always associated together in a lichen . One fungus, for example, can form lichens with a variety of different algae . The thalli produced by a given fungal symbiont with its differing partners will be similar, and the secondary metabolites identical, indicating that the fungus has the dominant role in determining the morphology of the lichen . Further, the same algal species can occur in association with different fungal partners . Lichens are known in which there is one fungus associated with two or even three algal species . Rarely, the reverse can occur, and two or more fungal species can interact to form the same lichen . </P> <P> Both the lichen and the fungus partner bear the same scientific name, and the lichens are being integrated into the classification schemes for fungi . The alga bears its own scientific name, which bears no relationship to that of the lichen or fungi . </P> <P> Depending on context, the entire lichen, or just the fungus that is part of the lichen . Both the lichen and the fungus that is a part of the lichen are currently (2014) given the same species name, which creates an ambiguity . An example of when "lichenized fungus" refers to just the fungus is when the fungus is grown in culture without a phycobiont . An example where "lichenized fungus" refers to the entire lichen is in a list of classified lichens . </P> <P> Some fungi can only be found living on lichens (obligate parasites), but are not considered part of the lichen . These are referred to as lichenolous fungi . </P>

What does each component of a lichen contribute to the symbiosis