Foliose refers to a type of lichen characterized by its leaf-like structure. These lichens typically have a flat, leafy appearance and are attached to their substrate at specific points, allowing them to spread out. Foliose lichens can be found in various environments, often growing on trees, rocks, and soil. These organisms are important for ecosystems as they contribute to soil formation and provide habitat for small organisms. Foliose lichens are sensitive to environmental changes, making them useful indicators of air quality. Common examples include species like Lobaria and Parmelia.