Lichens

A lichen is the fruit of a symbiosis between an algae and a fungus: the fungus protects the algae, giving it water and mineral salts and the algae produces sugars and other products, which it shares with the fungus. An excellent indicator of air quality, capable of withstanding extreme living conditions, there are a great many species in the Orgère forest, including wolf lichen, which grows almost exclusively on the larch tree. With a bright sulphur-yellow colour, it is the only toxic lichen in France. Legend has it that it takes its name from its alleged use as a poison against the wolf.