Description: Lichen is a symbiotic organism resulting from the association between a fungus and one or more algae, although it can also include cyanobacteria. This symbiotic relationship allows both organisms to mutually benefit: the fungus provides a protected and moist environment, while the algae perform photosynthesis, producing nutrients that feed the fungus. Lichens are extremely versatile and can be found in a variety of habitats, from rocks and trees to arid soils and deserts. Their morphology is diverse, appearing in crustose, foliose, or fruticose forms. Additionally, lichens are bioindicators of air quality, as they are sensitive to pollution, making them valuable tools for environmental monitoring. Their ability to survive in extreme conditions, such as very low or high temperatures, and their resistance to desiccation, allows them to colonize inhospitable environments. This adaptability and their ecological role make them essential in ecosystems, contributing to soil formation and providing habitats for other organisms.