Peltigera

Peltigera is a genus of lichen comprising approximately 150 species, primarily found in temperate and boreal regions worldwide. These lichens are characterized by their distinctive, often umbrella-like or flat, lobed, or fruticose growth forms, which can vary in color from grayish-green to brown, yellow, or even red. The genus is notable for its ability to thrive in a wide range of habitats, including forests, grasslands, and even urban areas, though some species are more specialized in certain environments.

Peltigera species are typically epiphytic or epilithic, growing on tree bark, rocks, or soil, though a few are saprophytic or parasitic. Their thallus (the main body of the lichen) often features a well-developed, often hairy or squamulose (scale-like) lower surface, which can be a key identifying feature. Many Peltigera species produce distinctive reproductive structures called pseudothecia, which are embedded in the thallus and release spores during fruiting.

One of the most well-known species is *Peltigera canina*, commonly called dog lichen or dog’s tongue lichen, due to its distinctive tongue-like lobes. This species is often found in moist, shaded environments and is sometimes used as a food source by some indigenous peoples. Another notable species is *Peltigera aphthosa*, which is known for its bright red or orange coloration and is sometimes cultivated as an ornamental plant.

Peltigera lichens play a crucial ecological role, contributing to soil formation and nutrient cycling in their habitats. They are also sensitive indicators of air quality, with many species declining in polluted environments. Conservation efforts often focus on protecting these lichens, particularly in regions where habitat degradation is a concern. Research into Peltigera continues to explore their biological diversity, chemical compositions, and potential medicinal or industrial applications.