Lobaria

Lobaria is a genus of foliose lichens, formerly classified in the family Lobariaceae, but now placed in the Peltigeraceae. They are commonly known as "lung wort" or "lungmoss" as their physical shape somewhat resembles a lung, and their ecological niche is similar to that of moss. Lobaria are unusual in that they have a three-part symbiosis, containing a fungus, and an alga (as other lichens do), but also a cyanobacterium that fixes nitrogen. Lobaria was originally described as a section of the eponymous genus Lichen by German naturalist Johann Christian Daniel von Schreber in 1786. It was proposed as a genus by Georg Franz Hoffmann in 1796. The establishment of Lobaria remained uncertain until Edvard Vainio also described it. He divided the genus into two sections based on different morphologies of the mature spore: Lobaria and Ricasolia. In 2013, the concept of family Lobariaceae was revised with the help of molecular phylogenetics, and, in addition to the creation of several new genera, Ricasolia was promoted to generic status. The family Lobariaceae was synonymized with the Peltigeraceae in 2018. Lichenicolous fungi that have been found growing on Lobaria species include Stigmidium lobariae, Calycina alstrupii, and Abrothallus halei. A Lobaria-associated actinobacterium, Subtercola lobariae, was isolated from L. retigera collected from the Jiaozi Snow Mountain in Yunnan Province, China. About a third of the bacteria found colonizing the thallus surface of Lobaria pulmonaria were found to belong to the Rhizobiales. This order of bacteria is well-known in their role as beneficial partners in plant-microbe interactions. Advantages conferred by the presence of the bacteria include auxin and vitamin production, nitrogen fixation, and stress protection. Although the bacteria were most prevalent on the thallus surface, they were shown to be able to penetrate into the interhyphal gelatinous matrix of the upper lichen cortical layer. Occasionally, some bacteria colonize the interior of the fungal hyphae.