Bromus tectorum, known as downy brome, drooping brome or cheatgrass, is a winter annual grass native to Europe, southwestern Asia, and northern Africa, but has become invasive in many other areas. It now is present in most of Europe, southern Russia, Japan, South Africa, Australia, New Zealand, Iceland, Greenland, North America and western Central Asia. In the eastern US B. tectorum is common along roadsides and as a crop weed, but usually does not dominate an ecosystem. It has become a dominant species in the Intermountain West and parts of Canada, and displays especially invasive behavior in the sagebrush steppe ecosystems where it has been listed as noxious weed. B. tectorum often enters the site in an area that has been disturbed, and then quickly expands into the surrounding area through its rapid growth and prolific seed production.
Biological soil crusts are communities of living organisms on the soil surface in arid and semi-arid ecosystems. They are found throughout the world with varying species composition and cover depending on topography, soil characteristics, climate, plant community, microhabitats, and disturbance regimes. Biological soil crusts perform important ecological roles including carbon fixation, nitrogen fixation and soil stabilization; they alter soil albedo and water relations and affect germination and nutrient levels in vascular plants. They can be damaged by fire, recreational activity, grazing and other disturbances and can require long time periods to recover composition and function. Biological soil crusts are also known as biocrusts or as cryptogamic, microbiotic, microphytic, or cryptobiotic soils.
Soil crusts are soil surface layers that are distinct from the rest of the bulk soil, often hardened with a platy surface. Depending on the manner of formation, soil crusts can be biological or physical. Biological soil crusts are formed by communities of microorganisms that live on the soil surface whereas physical crusts are formed by physical impact such as that of raindrops.
Charles Christian Plitt was a botanist and lichenologist. Species of lichens that have been named in Charles Plitt's honor are: Pyrenula plittii R.C.Harris, Xanthoparmelia plittii (Gyelnk) Hale, and Pertusaria plittiana Erichsen.
Rhizoplaca is a genus of lichenized fungi in the family Lecanoraceae. Members of the genus are commonly called rimmed navel lichens because of their umbilicate growth form and lecanorine apothecia, also rock-posy lichen and rockbright.
Dictyonema is a genus of mainly tropical basidiolichens in the family Hygrophoraceae.
Carolyn Wilson Harris was vice president of the Sullivant Moss Society during 1904–1905 and charge of the Lichen Department from 1901 to 1905. She also wrote many articles on various lichen genera and species. She was known for being an indefatigable worker, and did much to popularize the study of lichens; her help was always given freely and cheerfully to those who applied to her for assistance in their studies.
Lois Clark (1884–1967) was an American botanist, bryologist, and professor who studied plants of the Northwestern United States, particularly the genus Frullania. She taught at the University of Idaho and the University of Washington. The standard author abbreviation L.Clark is used to indicate this person as the author when citing a botanical name.
Theodore Christian Frye was an American botany professor and one of the world's leading experts on bryology.
John Walter Thomson Jr. (1913–2009) was a Scottish-born American botanist and lichenologist, sometimes referred to as the "Dean of North American Lichens".
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.
Per Magnus Jørgensen is a Norwegian botanist and lichenologist, and Professor Emeritus of systematic botany at the University of Bergen. He is known for his work on the lichen families Pannariaceae and Collemataceae. Jørgensen was awarded the Acharius Medal in 2021 for his lifetime contributions to lichenology.
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.
Bruce Pettit McCune is an American lichenologist, botanist, plant ecologist, and software developer for analysis of ecological data.
Jayne Belnap is an American soil ecologist. Her expertise lies in desert ecologies and grassland ecosystems.
Trapeliopsis steppica is a species of squamulose lichen in the family Trapeliaceae. It is found in the western United States, where it grows on soil in grassland and in shrub–steppe.
Ochrolechia upsaliensis is a species of crustose lichen in the family Ochrolechiaceae. Found in the Northern Hemisphere, it is commonly known as the tundra saucer lichen.
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.
Lobaria anomala, commonly known as the netted specklebelly, is a species of foliose lichen in the family Peltigeraceae. It is found in coastal western North America, where it grows on trees in humid environments. The lichen was first described as a new species in 1987 as a species of Pseudocyphellaria, though it had been mentioned in scientific papers before.
Gallowayella galericulata is a species of corticolous and lignicolous lichen in the family Teloschistaceae. This species has small, orange, foliose (leafy), loosely adnate thalli that form either compact colonies or spread extensively. The lobes of the thallus are typically curved inward, and often form a characteristic helmet- or hood-like shape. Found in dry regions of the western United States, it colonises bark and wood, particularly favouring dry twigs of various shrubs and trees.
