Lichen

A lichen consists of two or more partners that live together symbiotically, with both of them benefitting from the alliance.  One partner is a fungus termed as the mycobiont.  While the other is either an algae, photobiont (usually green) or a cyanobacterium, sometimes called blue-green algae although it is more closely related to bacteria than algae. The algae or cyanobacterium is able to use sunlight to produce essential nutrients by photosynthesis that feeds both organisms.  The fungus creates a foundation, known as a thallus, in which they both live.  The fungus also produces chemical compounds that may act as sunscreen to protect its photosynthetic partner.