… by genus: Peltigera
Latin: pelta means shield and gerein (Gr.) means bearing; so carrying or bearing a shield. The thallus in this group is foliose. They are generally large, regularly reaching sizes of 20 cm to 30 cm in width. The thalline lobes are typically oblong. Colour varies depending on whether they are wet or not. The underside contains rhizines and is felt-like due to a mat of hyphae. Chemical tests are unreliable in their identification. The main fruiting bodies are apothecia which lack a thalline margin (lecanorine). Apothecial discs are flat to convex. Spores are 3 to 9 septate. The photobiont is typically the blue-green algae Nostoc. They require careful examination to determine the species. They are more common in the West of Ireland than in other areas.