[2] Commonly known as the dog or pelt lichens, species of Peltigera are often terricolous (growing on soil), but can also occur on moss, trees, rocks, and many other substrates in many parts of the world.

Lower surfaces are typically without a cortex (unlike other foliose lichens),[5] and cottony, often with fungal hyphae fused to form a network of veins.

[11] In a comparative analysis of both morphological and chemical characteristics as well as sequences of large subunit nuclear ribosomal DNA, it was shown that the genus Peltigera is monophyletic.

According to Bruce McCune and Daphne Stone (2022), while molecular analysis showed three distinct genetic clades, maintaining them as separate species proved impractical for conservation and research purposes.

[16] Peltigera lichens serve as important hosts for diverse microbial communities, functioning as miniature ecosystems rather than simply dual symbiotic partnerships.

For example, P. rufescens has been found to host over 90 different yeast isolates representing 18 distinct taxa, demonstrating the complexity of these microbial associations.

These lichens appear to acquire key microbial symbionts directly from the soils where they grow, suggesting their local environments serve as reservoirs for their microbiome diversity.

[17] The yeasts associated with Peltigera belong to several major taxonomic groups, including members of the classes Tremellomycetes, Cystobasidiomycetes, and other basidiomycetes.

Studies have shown that these yeasts can maintain metabolic activity even at low temperatures, potentially supporting the lichen's overall survival and ecological functionality.

Research in southern Chile has demonstrated that Peltigera lichens can significantly enhance gamma diversity across landscapes by functioning as island-like habitats that support specialised bacteria and yeasts.

This suggests that Peltigera species play a broader ecological role beyond their own survival, contributing to local microbial biodiversity patterns and ecosystem processes.