About Peltigera venosa (L.) Hoffm.
Peltigera venosa, commonly called the fan lichen, is a species of foliose lichen belonging to the family Peltigeraceae. Carl Linnaeus first formally described this species in his 1753 publication Species Plantarum, under the name Lichen venosus. In 1789, German botanist Georg Franz Hoffmann reclassified the species, moving it to the genus Peltigera. Peltigera venosa occurs naturally in temperate and boreal regions across North America, Europe, and Asia; it is also occasionally found in drier climates, such as the mountainous area of Arizona. The color of its thallus changes based on hydration level: it is deep green when wet, and dark grey-green when dry. The lobes that make up the thallus are rounded to fan-shaped, and measure between 10 and 15 millimeters wide. The upper surface of the thallus is smooth, while the lower surface is white with raised black veins. Its apothecia are almost always present, and are round, flat, and reddish-brown.
