Lungwort, Lobaria pulmonaria

The lungwort, or lung lichen (Lobaria pulmonaria), is a lichen that is commonly found in humid forests composed of both deciduous and conifer trees throughout Asia, Europe, and North America. 
The presence of lungwort is a clear indicator that the air in the vicinity is of high quality as it is unable to survive in developed and polluted areas.
Mammals and insects alike use lungwort as a food source, and birds use it as a nesting material. This lichen has also been used for human consumption, and, due to the fact that its appearance is so similar to that of the human lung (hence the name), it has also been used to treat pulmonary related diseases and disorders.
Lungwort is classified as a cyanolichen, although it consists mostly of green algae, because it contains nitrogen-fixing bacteria that will enrich the soil where it decomposes.