Umbilicaria

Umbilicaria is a genus of lichenized fungi in the family Umbilicariaceae. The genus was circumscribed by Swedish botanist Erik Acharius in 1803. Umbilicaria species are characterized by their thallus, which is typically crustose, meaning it forms a thin, crust-like layer on the substrate. The thallus is often described as umbilicate, meaning it has a central depression or pit, which gives the genus its name. The genus is cosmopolitan, with species found in various habitats around the world, including forests, grasslands, and even on rocks and trees.

The genus Umbilicaria includes several species, some of which are of particular interest to lichenologists. For example, Umbilicaria esculenta, commonly known as the "edible lichen," is valued for its culinary uses. It has a distinctive taste and is used in traditional medicine in some cultures. Another notable species is Umbilicaria bituminosa, which is known for its black, shiny thallus and is often found in tropical regions.

Umbilicaria species are typically photobiont-free, meaning they do not have an algal partner. Instead, they are mycobionts, relying solely on their fungal component for photosynthesis. This makes them unique among lichens. The genus is also notable for its reproductive structures, which include apothecia, or fruiting bodies, that produce ascospores.

In summary, Umbilicaria is a genus of lichenized fungi known for its umbilicate thallus and cosmopolitan distribution. It includes species with culinary and medicinal value, and is characterized by its mycobiont-only nature and distinctive reproductive structures.