What is umbilicaria?

Umbilicaria is a genus of foliose lichens that grow on rocks, soil, and trees in various habitats worldwide. The thallus is variable in size and shape, typically characterized by a curled or lobed margin and a well-developed central depression called the umbilicus, which gives the genus its name. The upper surface is usually dark green or brown, while the lower surface is often lighter with white or brown rhizines. Umbilicaria species are widely used in traditional medicine and as a food source in some cultures. They also have ecological importance as nitrogen-fixing symbionts of cyanobacteria and can serve as indicators of air pollution. Genetics and metabolomics studies have recently revealed the chemical and functional diversity of the genus and its potential value for biotechnological applications.