Peltigera aphthosa
Conservation status
Secure  (NatureServe)
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Peltigerales
Family:	Peltigeraceae
Genus:	Peltigera
Species:	P. aphthosa
Binomial name
Peltigera aphthosa (L.) Willd. (1787)
Synonyms
Lichen aphthosus L. (1753)

Peltigera aphthosa is a species of lichen known by the common names green dog lichen, leafy lichen, felt lichen, and common freckle pelt. It has a circumpolar distribution, occurring throughout the Arctic, boreal, and temperate regions of the Northern Hemisphere.^[1]

This lichen has a large thallus that may exceed one meter in width. It is divided into lobes up to about 10 centimeters long and 6 wide. It is green, becoming pale as it dries. The thallus is dotted with cephalodia, which contains one of the two symbionts, a species of Nostoc. The other is a species of Coccomyxa. These perform photosynthesis, and the Nostoc also fixes nitrogen. The lichen produces large apothecia, a reproductive structure.^[1]

This widespread lichen grows in a variety of habitat types, including Arctic ecosystems. It grows in alpine climates in the southern parts of its distribution.^[1]

This lichen was noted to absorb aluminum and silicon from the ash released from the 1980 eruption of Mount St. Helens.^[1]

It is a known host to the lichenicolous fungus species Lichenopeltella santessonii.^[2]

• Palmqvist, K. (1993). Photosynthetic CO₂-use efficiency in lichens and their isolated photobionts: the possible role of a CO₂-concentrating mechanism. Planta 191 48–56.
• Paulsrud, P., et al. (1998). Cyanobiont specificity in some Nostoc-containing lichens and in a Peltigera aphthosa photosymbiodeme. New Phytologist 139 517–24.
• Paulsrud, P., et al. (2001). Field investigations on cyanobacterial specificity in Peltigera aphthosa. New Phytologist 152 117–23.

Wikimedia Commons has media related to Peltigera aphthosa.

• The Nature Conservancy
• USDA Plants Profile