Usnea is a genus of mostly pale grayish-green fruticose lichens that grow like leafless mini-shrubs or tassels anchored on bark or twigs. The genus is in the family Parmeliaceae. It grows all over the world. Members of the genus are commonly called old man's beard, beard lichen, or beard moss.
Cryptothecia is a genus of white to greenish crustose lichens that grow on bark, wood, or leaves, in tropical or subtropical areas worldwide. It has a conspicuous prothallus that develops around its periphery which can be bright red in some species, hence the common name wreath lichen. The main vegetative body (thallus) lacks a cortex (ecorticate and is often immersed in the substrate or byssoid. The medulla is white, well defined, and often peppered with calcium oxalate crystals. Ascomata are not well defined, being cushions of soft white mycelium immersed in the medullary tissue, hence the name from the Greek krypto = "to conceal" and theke = "a container or sheath". It contains Trentepohlia, a green alga, as its photobiont partner.
Hypogymnia is a genus of foliose lichens in the family Parmeliaceae. They are commonly known as tube lichens, bone lichens, or pillow lichens. Most species lack rhizines that are otherwise common in members of the Parmeliaceae, and have swollen lobes that are usually hollow. Other common characteristics are relatively small spores and the presence of physodic acid and related lichen products. The lichens usually grow on the bark and wood of coniferous trees.
Bulbothrix is a genus of lichen-forming fungi in the family Parmeliaceae. This genus is synonymous with Bulbothricella V.Marcano, S.Mohali & A.Morales. Bulbothrix was circumscribed by lichenologist Mason E. Hale in 1974 with Bulbothrix semilunata as the type species.
Parmotrema is a genus of lichen belonging to the family Parmeliaceae. It is a large genus, containing an estimated 300 species, with a centre of diversity in subtropical regions of South America and the Pacific Islands.
Dictyonema is a genus of mainly tropical basidiolichens in the family Hygrophoraceae.
Protousnea is a genus of lichenised ascomycetes in the large family Parmeliaceae. It contains two accepted species. Protousnea species have a fruticose growth form, similar to beard lichens. The genus is endemic to southern South America. The genus was circumscribed in 1976 by Hildur Krog as a segregate genus from Usnea.
Thomas Hawkes Nash III is an American lichenologist. His research is about the biology and ecology of lichens, and the effects of air pollution on plants and lichens. He is known as an authority on the family Parmeliaceae. During his long career at the Arizona State University, he helped develop the lichen herbarium into a world-class collection with over 100,000 specimens representing more than 5000 species. In 2010, the year of his retirement, he was awarded the Acharius Medal for lifetime achievements in lichenology, and the following year had a Festschrift published in his honor.
Robert "Bob" Shaw Egan is a botanist and lichenologist, specializing in the family Parmeliaceae. He was the president of the American Bryological and Lichenological Society from 1999 to 2001.
Candelariella antennaria, or the pussytoes eggyolk lichen, is a lichen commonly distributed in North America, and has been observed in South America, Asia, Australia, and Europe. It is characterized by its gray thallus and bright yellow apothecia, as well as its very small size.
Klaus Kalb is a German lichenologist and an authority on tropical lichens.
Philippe Clerc is a Swiss lichenologist. A Festschrift was dedicated to him in 2020, on the occasion of his retirement from the Conservatory and Botanical Garden of the City of Geneva, where he worked from 1993 to 2020. Clerc is an authority on the beard lichens, and has had nearly 100 publications on this and other topics, such as the lichen flora of Switzerland.
Usnea hirta is a species of beard lichen in the family Parmeliaceae. It was one of 80 lichen species first formally described by Carl Linnaeus in his 1753 work Species Plantarum. Friedrich Heinrich Wiggers transferred it to the genus Usnea in 1780. The lichen is sensitive to air pollution, and is often used as a biomonitor of sulphur dioxide. Usnea hirta has an extensive worldwide distribution, and it is morphologically variable, which has led to numerous intraspecific taxa being proposed in its taxonomic history.
Angiactis is a genus of crustose lichens of uncertain familial placement in the order Arthoniales. It has four species.
Robert Lücking is a German lichenologist. He earned his master's and PhD from the University of Ulm, focusing on the taxonomy, ecology, and biodiversity of foliicolous lichens. He has received numerous awards for his work, including the Mason E. Hale Award for his doctoral thesis, the Augustin Pyramus de Candolle prize for his monograph, and the Tuckerman Award twice for his publications in the scientific journal The Bryologist. Since 2015, he has been serving as the curator of lichens, fungi, and bryophytes at the Berlin Botanical Garden and Botanical Museum. Several lichen species and a genus have been named in his honour.
Usnea leana is a species of fruticose lichen in the family Parmeliaceae. Found in the Galápagos Islands, it characterized by its pendulous thallus, branches covered with point-like pseudocyphellae, and the presence of galbinic acid. This lichen is currently known to be endemic to the Galápagos, with only two known localities representing its distribution.
Usnea mayrhoferi is a species of fruticose lichen in the family Parmeliaceae. It is found in the Galápagos Islands.
Usnea patriciana is a rare species of fruticose lichen in the family Parmeliaceae. It is endemic to the Galápagos Islands. This beard lichen has a shrubby appearance with cylindrical branches and distinct black pigmentation at its base.
Usnea subcomplecta is a species of fruticose lichen in the family Parmeliaceae. It is found in the Galápagos Islands. It is characterized by its flaccid branches, blackened trunk, and pruinose cortex surface.
Usnea galapagona is a species of beard lichen in the family Parmeliaceae. It is endemic to the Galápagos Islands. The lichen is easily recognized by its special structure. It has a tough, glass-like outer layer, a thick central core, and a very faint, almost invisible inner layer. This lichen stands upright and has a reddish colour near its base. Its branches split unevenly and are generally few in number, without any small, hair-like structures.
