Peltigera

Peltigera
Peltigera leucophlebia
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Peltigerales
Family:	Peltigeraceae
Genus:	Peltigera Willd.
Type species
Peltigera canina (L.) Willd.

Peltigera is a genus of approximately 91 species of foliose lichens in the family Peltigeraceae. Commonly known as the dog lichen, lichens 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.

Most Peltigera species have the cyanobacterium as the dominant phytobiont but some have the chlorophyte Coccomyxa in which case they also have small gall-like growths containing Nostoc. Because of their ability to fix nitrogen from the atmosphere, such lichens are influential in soil composition and generation.

Species of Peltigera are foliose, with broad lobed thalli. Although the size of the thalli is variable and species-dependent, in some species the thalli can grow quite large, up to 30 cm in diameter. The color of the upper surface may range from drab gray, brown or greenish. Lower surfaces are typically without a cortex (unlike other foliose lichens), and cottony, often with fungal hyphae fused to form a network of veins. The reproductive structures isidia, soredia or lobules may be present in some species.

All species of Peltigera associate with the nitrogen-fixing cyanobacteria .

P. didactyla is a common pioneer species on disturbed soils and nutrient poor grasslands in Western Europe. At Deception Island in the South Shetlands archipelago, P. didactyla was found growing extensively on ash from volcanic eruptions that occurred in the late 1960s and 1970.

In 1753, Linnaeus first described the species Lichen apthosus and L. caninus back when all known lichens were grouped into the genus Lichen. Later, in 1787, Willdenow circumscribed the genus Peltigera, and redescribed P. aphthosa and P. canina.

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Wikipedia