169-502: See § Synonyms Stem rust , also known as cereal rust , black rust , red rust or red dust , is caused by the fungus Puccinia graminis , which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat , durum wheat , barley and triticale . These diseases have affected cereal farming throughout history. The annual recurrence of stem rust of wheat in North Indian plains
338-477: A gametangium , a specialized cell structure that becomes a fertile gamete -producing cell. The gametangium develops into a zygospore , a thick-walled spore formed by the union of gametes. When the zygospore germinates, it undergoes meiosis , generating new haploid hyphae, which may then form asexual sporangiospores . These sporangiospores allow the fungus to rapidly disperse and germinate into new genetically identical haploid fungal mycelia. The spores of most of
507-421: A monophyletic origin of fungi. The taxonomy of fungi is in a state of constant flux, especially due to research based on DNA comparisons. These current phylogenetic analyses often overturn classifications based on older and sometimes less discriminative methods based on morphological features and biological species concepts obtained from experimental matings . There is no unique generally accepted system at
676-550: A writing system , built huge pyramids and temples , had a complex calendar , and developed the concept of zero around 400 CE. The first recorded European references to North America are in Norse sagas where it is referred to as Vinland . The earliest verifiable instance of pre-Columbian trans-oceanic contact by any European culture with the North America mainland has been dated to around 1000 CE. The site , situated at
845-481: A bridge from one growing season to another. In other cases the fungus passes between winter wheat and spring wheat, meaning that it has a cereal host all year round. Since the urediniospores are wind dispersed, this can occur over large distances. Note that this cycle consists simply of vegetative propagation – urediniospores infect one wheat plant, leading to the production of more urediniospores that then infect other wheat plants. Puccinia graminis produces all five of
1014-735: A cup-shaped fruit body that is often macroscopic and holds the hymenium , a layer of tissue containing the spore-bearing cells. The fruit bodies of the basidiomycetes ( basidiocarps ) and some ascomycetes can sometimes grow very large, and many are well known as mushrooms . The growth of fungi as hyphae on or in solid substrates or as single cells in aquatic environments is adapted for the efficient extraction of nutrients, because these growth forms have high surface area to volume ratios . Hyphae are specifically adapted for growth on solid surfaces, and to invade substrates and tissues. They can exert large penetrative mechanical forces; for example, many plant pathogens , including Magnaporthe grisea , form
1183-650: A direct source of human food , in the form of mushrooms and truffles ; as a leavening agent for bread; and in the fermentation of various food products, such as wine , beer , and soy sauce . Since the 1940s, fungi have been used for the production of antibiotics , and, more recently, various enzymes produced by fungi are used industrially and in detergents . Fungi are also used as biological pesticides to control weeds, plant diseases, and insect pests. Many species produce bioactive compounds called mycotoxins , such as alkaloids and polyketides , that are toxic to animals, including humans. The fruiting structures of
1352-721: A federal quarantine was established against the sale of stem rust susceptible barberry in those states that were part of the program. A barberry testing program was created to ensure that only those species and varieties of barberry that are immune to stem rust will be grown in the quarantine area. In 1969 two races not detected before in Australia were found and for decades one hypothesis was an African origin, and in 2018 DNA analysis confirmed that, specifically South African . South Africa itself has an ongoing problem with various stem rust outbreaks which requires better response, including an indigenous breeding for resistance program. There
1521-498: A few other locations in the US, and overall across the US, this race declined 97–98 in favor of other races, and not because of overall Pg decline. As listed by Species Fungorum ; The stem rust fungus attacks the parts of the plant that are above ground. Spores that land on green wheat plants form a pustule that invades the outer layers of the stalk. Infected plants produce fewer tillers and set fewer seed, and in cases of severe infection
1690-615: A few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies . Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases (e.g., rice blast disease ) or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses an enormous diversity of taxa with varied ecologies, life cycle strategies, and morphologies ranging from unicellular aquatic chytrids to large mushrooms. However, little
1859-496: A fungal mycelium separates into pieces, and each component grows into a separate mycelium. Mycelial fragmentation and vegetative spores maintain clonal populations adapted to a specific niche , and allow more rapid dispersal than sexual reproduction. The "Fungi imperfecti" (fungi lacking the perfect or sexual stage) or Deuteromycota comprise all the species that lack an observable sexual cycle. Deuteromycota (alternatively known as Deuteromycetes, conidial fungi, or mitosporic fungi)
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#17331216424702028-405: A high degree of metabolic versatility that allows them to use a diverse range of organic substrates for growth, including simple compounds such as nitrate , ammonia , acetate , or ethanol . In some species the pigment melanin may play a role in extracting energy from ionizing radiation , such as gamma radiation . This form of " radiotrophic " growth has been described for only a few species,
2197-457: A host, John Craigie , a Canadian pathologist, identified the function of the spermogonium in 1927. Due to the useful nature of both barberry and wheat plants, they were eventually brought to North America by European colonists. Barberry was used for many things like making wine and jams from the berries to tool handles from the wood. Ultimately, as they did in Europe, the colonists began to notice
2366-484: A large number of races of its own . The virulent new race, against which most current wheat strains show no resistance, was identified in 1999. The race was named TTKSK (e.g. isolate Ug99), named after the country where it was identified ( Uganda ) and the year of its discovery (1999). It spread to Kenya , then Ethiopia , Sudan and Yemen , and becomes more virulent as it spreads. An epidemic of stem rust on wheat caused by race TTKSK spread across Africa , Asia and
2535-573: A motile zoospore , enabling them to propel themselves through water and enter their amphibian host. Other examples of aquatic fungi include those living in hydrothermal areas of the ocean. As of 2020, around 148,000 species of fungi have been described by taxonomists , but the global biodiversity of the fungus kingdom is not fully understood. A 2017 estimate suggests there may be between 2.2 and 3.8 million species. The number of new fungi species discovered yearly has increased from 1,000 to 1,500 per year about 10 years ago, to about 2,000 with
2704-402: A new haploid mycelium. Sexual reproduction in basidiomycetes is similar to that of the ascomycetes. Compatible haploid hyphae fuse to produce a dikaryotic mycelium. However, the dikaryotic phase is more extensive in the basidiomycetes, often also present in the vegetatively growing mycelium. A specialized anatomical structure, called a clamp connection , is formed at each hyphal septum. As with
2873-578: A part of Denmark) and Mexico classified as Latin American). It is unknown with certainty how and when first human populations first reached North America. People were known to live in the Americas at least 20,000 years ago, but various evidence points to possibly earlier dates. The Paleo-Indian period in North America followed the Last Glacial Period, and lasted until about 10,000 years ago when
3042-431: A peak of more than 2,500 species in 2016. In the year 2019, 1,882 new species of fungi were described, and it was estimated that more than 90% of fungi remain unknown. The following year, 2,905 new species were described—the highest annual record of new fungus names. In mycology, species have historically been distinguished by a variety of methods and concepts. Classification based on morphological characteristics, such as
3211-648: A period of mountain building called the Laramide orogeny , between 80 and 55 mya. The formation of the Isthmus of Panama that connected the continent to South America arguably occurred approximately 12 to 15 mya, and the Great Lakes (as well as many other northern freshwater lakes and rivers) were carved by receding glaciers about 10,000 years ago. North America is the source of much of what humanity knows about geologic time periods. The geographic area that would later become
3380-571: A powerful earthquake killed seven people in 2009. Volcanic eruptions are common in the region. In 1968, the Arenal Volcano , in Costa Rica, erupted and killed 87 people. Fertile soils from weathered volcanic lavas have made it possible to sustain dense populations in agriculturally productive highland areas. Central America has many mountain ranges ; the longest are the Sierra Madre de Chiapas ,
3549-516: A process called branching , or occasionally growing hyphal tips fork, giving rise to two parallel-growing hyphae. Hyphae also sometimes fuse when they come into contact, a process called hyphal fusion (or anastomosis ). These growth processes lead to the development of a mycelium , an interconnected network of hyphae. Hyphae can be either septate or coenocytic . Septate hyphae are divided into compartments separated by cross walls (internal cell walls, called septa, that are formed at right angles to
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#17331216424703718-497: A relationship between barberry and stem rust epidemics in wheat. Laws were enacted in many New England colonies, but as the farmers moved west, the problem with stem rust moved with them and began to spread to many areas, creating a devastating epidemic in 1916. It was not until two years later in 1918 that the United States created a program to remove barberry. The program was one that was supported by state and federal entities and
3887-567: A small drop of water (Buller's drop), which upon contact with the spore leads to its projectile release with an initial acceleration of more than 10,000 g ; the net result is that the spore is ejected 0.01–0.02 cm, sufficient distance for it to fall through the gills or pores into the air below. Other fungi, like the puffballs , rely on alternative mechanisms for spore release, such as external mechanical forces. The hydnoid fungi (tooth fungi) produce spores on pendant, tooth-like or spine-like projections. The bird's nest fungi use
4056-581: A structure called an appressorium that evolved to puncture plant tissues. The pressure generated by the appressorium, directed against the plant epidermis , can exceed 8 megapascals (1,200 psi). The filamentous fungus Paecilomyces lilacinus uses a similar structure to penetrate the eggs of nematodes . The mechanical pressure exerted by the appressorium is generated from physiological processes that increase intracellular turgor by producing osmolytes such as glycerol . Adaptations such as these are complemented by hydrolytic enzymes secreted into
4225-482: A terrestrial lifestyle necessitated a diversification of ecological strategies for obtaining nutrients, including parasitism , saprobism , and the development of mutualistic relationships such as mycorrhiza and lichenization. Studies suggest that the ancestral ecological state of the Ascomycota was saprobism, and that independent lichenization events have occurred multiple times. In May 2019, scientists reported
4394-668: A third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph (sexual reproduction) and the anamorph (asexual reproduction). Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules . Asexual reproduction occurs via vegetative spores ( conidia ) or through mycelial fragmentation . Mycelial fragmentation occurs when
4563-540: A variety of reactions, including curiosity, trading, cooperation, resignation, and resistance. The indigenous population declined substantially following European arrival, primarily due to the introduction of Eurasian diseases, such as smallpox , to which the indigenous peoples lacked immunity, and because of violent conflicts with Europeans. Indigenous culture changed significantly and their affiliation with political and cultural groups also changed. Several linguistic groups died out , and others changed quite quickly. On
4732-662: Is heteroecious , requiring two hosts to complete its life cycle – the cereal host and the alternate host . There are many species in Berberis and Mahonia (and their hybrid genus x Mahoberberis ) that are susceptible to stem rust, but the common barberry ( B. vulgaris ) is considered to be the most important alternate host. P. graminis is macrocyclic (exhibits all five of the spore types that are known for rust fungi). P. graminis can complete its life cycle either with or without barberry (the alternate host). P. g. tritici ' s obligately biotrophic lifestyle involves
4901-841: Is a continent in the Northern and Western Hemispheres . North America is bordered to the north by the Arctic Ocean , to the east by the Atlantic Ocean , to the southeast by South America and the Caribbean Sea , and to the west and south by the Pacific Ocean . The region includes the Bahamas , Bermuda , Canada , the Caribbean , Central America , Clipperton Island , Greenland , Mexico , Saint Pierre and Miquelon , Turks and Caicos Islands , and
5070-640: Is a very large continent that extends from north of the Arctic Circle to south of the Tropic of Cancer . Greenland, along with the Canadian Shield , is tundra with average temperatures ranging from 10 to 20 °C (50 to 68 °F), but central Greenland is composed of a very large ice sheet. This tundra radiates throughout Canada, but its border ends near the Rocky Mountains (but still contains Alaska) and at
5239-577: Is also strongly supported by molecular phylogenetics . This fungal group is distinct from the structurally similar myxomycetes (slime molds) and oomycetes (water molds). The discipline of biology devoted to the study of fungi is known as mycology (from the Greek μύκης mykes , mushroom). In the past, mycology was regarded as a branch of botany , although it is now known that fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of
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5408-511: Is an ancient craton which forms the geologic core of North America; it formed between 1.5 and 1.0 billion years ago during the Proterozoic eon. The Canadian Shield is the largest exposure of this craton. From the Late Paleozoic to Early Mesozoic eras, North America was joined with the other modern-day continents as part of the supercontinent Pangaea , with Eurasia to its east. One of
5577-417: Is considerable genetic diversity within the species P. graminis , and several special forms, forma specialis , which vary in host range have been identified. P. graminis is a member of the phylum Basidiomycota within the kingdom Fungi . The characteristic rust color on stems and leaves is typical of a general stem rust as well as any variation of this type of fungus. Different from most fungi,
5746-404: Is considered to be the publication of Pier Antonio Micheli 's 1729 work Nova plantarum genera . Micheli not only observed spores but also showed that, under the proper conditions, they could be induced into growing into the same species of fungi from which they originated. Extending the use of the binomial system of nomenclature introduced by Carl Linnaeus in his Species plantarum (1753),
5915-734: Is grown in a broad range of environments. This means that breeding programs would have extensive work remaining to get resistance into regionally adapted germplasms even after resistance is identified. Similarly, in 2014, a Ug99 race called "Digalu" emerged and devastated the Digalu variety in Ethiopia. JRCQC is a race affecting Durum in Ethiopia . Affects barley. Affects barley. Successfully overwintered in Kansas in 1989/90, and in Texas and Kansas in 1990/91, and so
6084-535: Is in present-day Panama at the Darien Gap on the Colombia -Panama border, placing almost all of Panama within North America. Alternatively, some geologists physiographically locate its southern limit at the Isthmus of Tehuantepec , Mexico, with Central America extending southeastward to South America from this point. The Caribbean islands, or West Indies, are considered part of North America. The continental coastline
6253-625: Is known of the true biodiversity of the fungus kingdom, which has been estimated at 2.2 million to 3.8 million species. Of these, only about 148,000 have been described, with over 8,000 species known to be detrimental to plants and at least 300 that can be pathogenic to humans. Ever since the pioneering 18th and 19th century taxonomical works of Carl Linnaeus , Christiaan Hendrik Persoon , and Elias Magnus Fries , fungi have been classified according to their morphology (e.g., characteristics such as spore color or microscopic features) or physiology . Advances in molecular genetics have opened
6422-630: Is long and irregular. The Gulf of Mexico is the largest body of water indenting the continent, followed by Hudson Bay . Others include the Gulf of Saint Lawrence and the Gulf of California . Before the Central American isthmus formed, the region had been underwater. The islands of the West Indies delineate a submerged former land bridge , which had connected North and South America via what are now Florida and Venezuela . There are several islands off
6591-463: Is no true 'start point' for this process. Here, the production of urediniospores is arbitrarily chosen as a start point. Urediniospores are formed in structures called uredinia, which are produced by fungal mycelia on the cereal host 1–2 weeks after infection. The urediniospores are dikaryotic (contain two un-fused, haploid nuclei in one cell) and are formed on individual stalks within the uredinium . They are spiny and brick-red. Urediniospores are
6760-638: Is not an accepted taxonomic clade and is now taken to mean simply fungi that lack a known sexual stage. Sexual reproduction with meiosis has been directly observed in all fungal phyla except Glomeromycota (genetic analysis suggests meiosis in Glomeromycota as well). It differs in many aspects from sexual reproduction in animals or plants. Differences also exist between fungal groups and can be used to discriminate species by morphological differences in sexual structures and reproductive strategies. Mating experiments between fungal isolates may identify species on
6929-548: Is part of North America geographically. In a geologic sense, Bermuda is not part of the Americas, but an oceanic island that was formed on the fissure of the Mid-Atlantic Ridge over 100 million years ago (mya). The nearest landmass to it is Cape Hatteras , North Carolina . However, Bermuda is often thought of as part of North America, especially given its historical, political and cultural ties to Virginia and other parts of
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7098-686: Is the Morrison Formation of the western U.S. Canada is geologically one of the oldest regions in the world, with more than half of the region consisting of Precambrian rocks that have been above sea level since the beginning of the Palaeozoic era. Canada's mineral resources are diverse and extensive. Across the Canadian Shield and in the north there are large iron, nickel, zinc , copper, gold, lead, molybdenum , and uranium reserves. Large diamond concentrations have been recently developed in
7267-516: Is the humid subtropical climate . This area has the wettest cities in the contiguous U.S. , with annual precipitation reaching 67 in (1,700 mm) in Mobile, Alabama . Stretching from the borders of the humid continental and subtropical climates, and going west to the Sierra Nevada , south to the southern tip of Durango , north to the border with tundra climate, the steppe / desert climates are
7436-531: Is the result of a large-scale collaborative research effort involving dozens of mycologists and other scientists working on fungal taxonomy. It recognizes seven phyla , two of which—the Ascomycota and the Basidiomycota—are contained within a branch representing subkingdom Dikarya , the most species rich and familiar group, including all the mushrooms, most food-spoilage molds, most plant pathogenic fungi, and
7605-468: Is their means of mobility , except for spores (a few of which are flagellated ), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the Eumycota ( true fungi or Eumycetes ), that share a common ancestor (i.e. they form a monophyletic group ), an interpretation that
7774-460: Is transported between regions). This type of dispersal is rare and is very difficult to predict. This is especially known to rarely occur across thousands of km/mi from South Africa to Western Australia. Fungus A fungus ( pl. : fungi or funguses ) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms . These organisms are classified as one of
7943-427: Is unclear and may be lower than other sexual processes. It is known to play a role in intraspecific hybridization and is likely required for hybridization between species, which has been associated with major events in fungal evolution. In contrast to plants and animals , the early fossil record of the fungi is meager. Factors that likely contribute to the under-representation of fungal species among fossils include
8112-451: The Age of Discovery and the early modern period . Present-day cultural and ethnic patterns reflect interactions between European colonists, indigenous peoples , enslaved Africans , immigrants from Europe, Asia, and descendants of these respective groups. Europe's colonization in North America led to most North Americans speaking European languages, such as English , Spanish , and French , and
8281-509: The Archaic period began. The classic stage followed the Archaic period, and lasted from approximately the 6th to 13th centuries. Beginning in 1000 AD, the Norse were the first Europeans to begin exploring and ultimately colonizing areas of North America. In 1492, the exploratory voyages of Christopher Columbus led to a transatlantic exchange , including migrations of European settlers during
8450-551: The Bering Strait during the Early-Middle Holocene . Prior to the arrival of European explorers and colonists in North America, the natives of North America were divided into many different polities, ranging from small bands of a few families to large empires. They lived in several culture areas , which roughly correspond to geographic and biological zones that defined the representative cultures and lifestyles of
8619-576: The British Columbia Coast , Western Canada , and Northern Canada . In the U.S., they include New England , the Mid-Atlantic , South Atlantic states , East North Central states , West North Central states , East South Central states , West South Central states , Mountain states , and Pacific states . The Great Lakes region and the Pacific Northwest include areas in both Canada and
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#17331216424708788-601: The Cambrian (542–488.3 Ma), also long before land plants. Fossilized hyphae and spores recovered from the Ordovician of Wisconsin (460 Ma) resemble modern-day Glomerales , and existed at a time when the land flora likely consisted of only non-vascular bryophyte -like plants. Prototaxites , which was probably a fungus or lichen, would have been the tallest organism of the late Silurian and early Devonian . Fungal fossils do not become common and uncontroversial until
8957-863: The Caribbean Plate , whereas the Juan de Fuca Plate and Cocos Plate border the North American Plate on its western frontier. The continent can be divided into four great regions (each of which contains many subregions): the Great Plains stretching from the Gulf of Mexico to the Canadian Arctic ; the geologically young, mountainous west, including the Rocky Mountains , the Great Basin , California , and Alaska ;
9126-553: The Cordillera Isabelia , and the Cordillera de Talamanca . Between the mountain ranges lie fertile valleys that are suitable for the people; in fact, most of the population of Honduras, Costa Rica, and Guatemala live in valleys. Valleys are also suitable for the production of coffee, beans, and other crops. The indigenous peoples of the Americas have many creation myths , based on which they assert that they have been present on
9295-459: The East Coast to eastern North Dakota , and stretching down to Kansas , is the humid continental climate featuring intense seasons, with a large amount of annual precipitation, with places like New York City averaging 50 in (1,300 mm). Starting at the southern border of the humid continental climate and stretching to the Gulf of Mexico (whilst encompassing the eastern half of Texas)
9464-608: The Inuit of the high Arctic arrived in North America much later than other native groups, evidenced by the disappearance of Dorset culture artifacts from the archaeological record and their replacement by the Thule people . During the thousands of years of native habitation on the continent, cultures changed and shifted. One of the oldest yet discovered is the Clovis culture (c. 9550–9050 BCE) in modern New Mexico . Later groups include
9633-632: The Latin fungus (mushroom), used in the writings of Horace and Pliny . This in turn is derived from the Greek word sphongos (σφόγγος 'sponge'), which refers to the macroscopic structures and morphology of mushrooms and molds; the root is also used in other languages, such as the German Schwamm ('sponge') and Schimmel ('mold'). The word mycology is derived from the Greek mykes (μύκης 'mushroom') and logos (λόγος 'discourse'). It denotes
9802-517: The Middle East , causing major concern due to the large numbers of people dependent on wheat for sustenance, thus threatening global food security . An outbreak of another virulent race of stem rust, TTTTF, took place in Sicily in 2016, suggesting that the disease is returning to Europe. Comprehensive genomic analysis of Puccinia graminis , combined with plant pathology and climate data, has pointed out
9971-544: The Middle East , causing major concern due to the large numbers of people dependent on wheat for sustenance, thus threatening global food security . In 2011, after it had spread into southern Africa , the Bill Gates Foundation donated $ 40 million towards research into Ug99, to be spent on critical infrastructure in Africa. Scientists are working on breeding strains of wheat that are resistant to UG99. However, wheat
10140-694: The Mississippian culture and related Mound building cultures, found in the Mississippi River valley and the Pueblo culture of what is now the Four Corners . The more southern cultural groups of North America were responsible for the domestication of many common crops now used around the world, such as tomatoes, squash , and maize . As a result of the development of agriculture in the south, many other cultural advances were made there. The Mayans developed
10309-734: The Red River Valley in North Dakota and Minnesota . Higher than normal inoculum production in South Central Oklahoma and the adjacent part of North Texas before the 1991 season resulted in an epidemic in North Central and northwestern Kansas. Virulent against barley bearing Rpg1 . Down to 26% of Pg s afflicting wheat in the US in 1995, 1% in 1996, and not at all in 1997 or 1998. Not found on barley in 1997 but found again in 1998. The first QCC race (since renamed QCCJ or QCCJB)
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#173312164247010478-450: The United States . North America covers an area of about 24,709,000 square kilometers (9,540,000 square miles), representing approximately 16.5% of the Earth 's land area and 4.8% of its total surface area. It is the third-largest continent by size after Asia and Africa , and the fourth-largest continent by population after Asia, Africa, and Europe . As of 2021 , North America's population
10647-545: The ascomycete genus Cochliobolus , and the ascomycete Pneumocystis jirovecii . The earliest mode of sexual reproduction among eukaryotes was likely homothallism, that is, self-fertile unisexual reproduction . Besides regular sexual reproduction with meiosis, certain fungi, such as those in the genera Penicillium and Aspergillus , may exchange genetic material via parasexual processes, initiated by anastomosis between hyphae and plasmogamy of fungal cells. The frequency and relative importance of parasexual events
10816-440: The biopolymer chitin. Fungal mycelia can become visible to the naked eye, for example, on various surfaces and substrates , such as damp walls and spoiled food, where they are commonly called molds . Mycelia grown on solid agar media in laboratory petri dishes are usually referred to as colonies . These colonies can exhibit growth shapes and colors (due to spores or pigmentation ) that can be used as diagnostic features in
10985-480: The first official name given to Mexico. North America includes several regions and subregions, each of which have their own respective cultural, economic, and geographic regions. Economic regions include several regions formalized in 20th- and 21st-century trade agreements, including NAFTA between Canada , Mexico , and the United States , and CAFTA between Central America , the Dominican Republic , and
11154-455: The roots of plants. As eukaryotes, fungi possess a biosynthetic pathway for producing terpenes that uses mevalonic acid and pyrophosphate as chemical building blocks . Plants and some other organisms have an additional terpene biosynthesis pathway in their chloroplasts, a structure that fungi and animals do not have. Fungi produce several secondary metabolites that are similar or identical in structure to those made by plants. Many of
11323-502: The spore types that are known for rust fungi . Spores are typically deposited close to the source, but long-distance dispersal is also well documented commonly out to hundreds of kilometres/miles. The following three categories of long-distance dispersal are known to occur: This can occur unassisted (the robust nature of the spores allows them to be carried long distances in the air and then deposited by rain-scrubbing) or assisted (typically on human clothing or infected plant material that
11492-474: The traditional eukaryotic kingdoms , along with Animalia , Plantae , and either Protista or Protozoa and Chromista . A characteristic that places fungi in a different kingdom from plants , bacteria , and some protists is chitin in their cell walls . Fungi, like animals, are heterotrophs ; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize . Growth
11661-453: The 1490s, building cities, putting the resident indigenous populations to work, raising crops for Spanish settlers and panning gold to enrich the Spaniards. Much of the indigenous population died due to disease and overwork, spurring the Spaniards on to claim new lands and peoples. An expedition under the command of Spanish settler, Hernán Cortés , sailed westward in 1519 to what turned out to be
11830-448: The 1950s," with the last U.S. outbreak in 1962 destroying 5.2% of the crop. Stem rust has been an ongoing problem dating back to Aristotle 's time (384–322 BC). An early ancient practice by the Romans was one where they would sacrifice red animals such as foxes, dogs, and cows to Robigus ( fem. Robigo ), the rust god. They would perform this ritual in the spring during a festival known as
11999-615: The Arctic, making Canada one of the world's largest producers. Throughout the Shield, there are many mining towns extracting these minerals. The largest, and best known, is Sudbury , Ontario. Sudbury is an exception to the normal process of forming minerals in the Shield since there is significant evidence that the Sudbury Basin is an ancient meteorite impact crater . The nearby, but less-known Temagami Magnetic Anomaly has striking similarities to
12168-635: The Caribbean islands. France took the western half of Hispaniola and developed Saint-Domingue as a cane sugar producing colony worked by black slave labor. Britain took Barbados and Jamaica , and the Dutch and Danes took islands previously claimed by Spain. Britain did not begin settling on the North American mainland until a hundred years after the first Spanish settlements, since it sought first to control nearby Ireland . The first permanent English settlement
12337-569: The Cod fish", in reference to the abundance of cod fish on the East Coast . Waldseemüller used the Latin version of Vespucci's name, Americus Vespucius, in its feminine form of "America", following the examples of "Europa", "Asia", and "Africa". Americus originated from Medieval Latin Emericus (see Saint Emeric of Hungary ), coming from the Old High German name Emmerich . Map makers later extended
12506-588: The Dutch Christiaan Hendrik Persoon (1761–1836) established the first classification of mushrooms with such skill as to be considered a founder of modern mycology. Later, Elias Magnus Fries (1794–1878) further elaborated the classification of fungi, using spore color and microscopic characteristics, methods still used by taxonomists today. Other notable early contributors to mycology in the 17th–19th and early 20th centuries include Miles Joseph Berkeley , August Carl Joseph Corda , Anton de Bary ,
12675-703: The Homobasidiomycetes (a taxon roughly equivalent to the mushroom-producing species of the Agaricomycetes ). Two amber -preserved specimens provide evidence that the earliest known mushroom-forming fungi (the extinct species Archaeomarasmius leggetti ) appeared during the late Cretaceous , 90 Ma. Some time after the Permian–Triassic extinction event (251.4 Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments ) formed, suggesting that fungi were
12844-419: The North America's southeastern coast, Spanish explorer Juan Ponce de León , who had accompanied Columbus's second voyage, visited and named in 1513 La Florida . As the colonial period unfolded, Spain, England, and France appropriated and claimed extensive territories in North America eastern and southern coastlines. Spain established permanent settlements on the Caribbean islands of Hispaniola and Cuba in
13013-553: The Robigalia in hopes of the wheat crop being spared from the destruction caused by the rust. Weather records from that time have been reexamined and it has been speculated that the fall of the Roman Empire was due to a string of rainy seasons in which the rust would have been more harsh, resulting in reduced wheat harvests. Laws banning barberry were established in 1660 in Rouen , France. This
13182-472: The Sudbury Basin. Its magnetic anomalies are very similar to the Sudbury Basin, and so it could be a second metal-rich impact crater. The Shield is also covered by vast boreal forests that support an important logging industry. The United States can be divided into twelve main geological provinces: Each province has its own geologic history and unique features. The geology of Alaska is typical of that of
13351-522: The U.S. North America occupies the northern portion of the landmass generally referred to as the New World, the Western Hemisphere , the Americas, or simply America, which, in many countries, is considered a single continent with North America a subcontinent . North America is the third-largest continent by area after Asia and Africa . North America's only land connection to South America
13520-552: The US on wheat in 1997 and 1998 – but only in the West across both years. On barley in 1997 but not 1998. 25% of Pg s on wheat in 1991. Traces found growing in northwest Illinois fields, also in 1991. 8% of all Pg s on wheat, barley, and oat in the US in 1997, and 31% in 1998. Displaced the previously dominant TPMK suddenly in 1998. 36% of Pg samples from wheat in 1991 in the United States. Unusually severe in southern Illinois in
13689-484: The United States has been the source of more varieties of dinosaurs than any other modern country. According to paleontologist Peter Dodson, this is primarily due to stratigraphy, climate and geography, human resources, and history. Much of the Mesozoic Era is represented by exposed outcrops in the many arid regions of the continent. The most significant Late Jurassic dinosaur-bearing fossil deposit in North America
13858-600: The United States, and Mexico. France , Italy , Portugal , Spain , Romania , Greece , and the countries of Latin America use a six-continent model , with the Americas viewed as a single continent and North America designating a subcontinent comprising Canada , the United States , Mexico, and Saint Pierre and Miquelon (politically part of France), and often including Greenland and Bermuda . North America has historically been known by other names, including Spanish North America, New Spain , and América Septentrional,
14027-575: The United States. North America is divided linguistically and culturally into two primary regions, Anglo-America and Latin America . Anglo-America includes most of North America, Belize , and Caribbean islands with English -speaking populations. There are also regions, including Louisiana and Quebec , with large Francophone populations; in Quebec , French is the official language. . The southern portion of North America includes Central America and non-English speaking Caribbean nations. The north of
14196-487: The air over long distances. Specialized mechanical and physiological mechanisms, as well as spore surface structures (such as hydrophobins ), enable efficient spore ejection. For example, the structure of the spore-bearing cells in some ascomycete species is such that the buildup of substances affecting cell volume and fluid balance enables the explosive discharge of spores into the air. The forcible discharge of single spores termed ballistospores involves formation of
14365-645: The apex) as in the case of some endophytic fungi, or growth by volume expansion during the development of mushroom stipes and other large organs. Growth of fungi as multicellular structures consisting of somatic and reproductive cells—a feature independently evolved in animals and plants —has several functions, including the development of fruit bodies for dissemination of sexual spores (see above) and biofilms for substrate colonization and intercellular communication . Fungi are traditionally considered heterotrophs , organisms that rely solely on carbon fixed by other organisms for metabolism . Fungi have evolved
14534-537: The area had shifted to the Aztec Empire , whose capital city Tenochtitlan was located further north in the Valley of Mexico . The Aztecs were conquered in 1521 by Hernán Cortés . During the so-called Age of Discovery , Europeans explored overseas and staked claims to various parts of North America, much of which was already settled by indigenous peoples. Upon Europeans' arrival in the " New World ", indigenous peoples had
14703-414: The basis of biological species concepts. The major fungal groupings have initially been delineated based on the morphology of their sexual structures and spores; for example, the spore-containing structures, asci and basidia , can be used in the identification of ascomycetes and basidiomycetes, respectively. Fungi employ two mating systems : heterothallic species allow mating only between individuals of
14872-490: The basis of comparisons of the rate of evolution in closely related groups. The oldest fossilizied mycelium to be identified from its molecular composition is between 715 and 810 million years old. For much of the Paleozoic Era (542–251 Ma), the fungi appear to have been aquatic and consisted of organisms similar to the extant chytrids in having flagellum-bearing spores. The evolutionary adaptation from an aquatic to
15041-544: The beer, wine, and bread yeasts. The accompanying cladogram depicts the major fungal taxa and their relationship to opisthokont and unikont organisms, based on the work of Philippe Silar, "The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research" and Tedersoo et al. 2018. The lengths of the branches are not proportional to evolutionary distances. Rozellomycetes Mitosporidium Paramicrosporidium Nucleophaga Metchnikovellea North America North America
15210-692: The brothers Louis René and Charles Tulasne , Arthur H. R. Buller , Curtis G. Lloyd , and Pier Andrea Saccardo . In the 20th and 21st centuries, advances in biochemistry , genetics , molecular biology , biotechnology , DNA sequencing , and phylogenetic analysis have provided new insights into fungal relationships and biodiversity , and have challenged traditional morphology-based groupings in fungal taxonomy . Most fungi grow as hyphae , which are cylindrical, thread-like structures 2–10 μm in diameter and up to several centimeters in length. Hyphae grow at their tips (apices); new hyphae are typically formed by emergence of new tips along existing hyphae by
15379-621: The cell wall giving the hypha its shape), with each compartment containing one or more nuclei; coenocytic hyphae are not compartmentalized. Septa have pores that allow cytoplasm , organelles , and sometimes nuclei to pass through; an example is the dolipore septum in fungi of the phylum Basidiomycota. Coenocytic hyphae are in essence multinucleate supercells. Many species have developed specialized hyphal structures for nutrient uptake from living hosts; examples include haustoria in plant-parasitic species of most fungal phyla, and arbuscules of several mycorrhizal fungi, which penetrate into
15548-432: The continent maintains recognized regions as well. In contrast to the common definition of North America, which encompasses the whole North American continent, the term "North America" is sometimes used more narrowly to refer only to four nations, Canada, Greenland, Mexico, and the U.S. The U.S. Census Bureau includes Saint Pierre and Miquelon, but excludes Mexico from its definition. The term Northern America refers to
15717-919: The continent's coasts; principally, the Arctic Archipelago, the Bahamas , Turks and Caicos , the Greater and Lesser Antilles , the Aleutian Islands (some of which are in the Eastern Hemisphere proper), the Alexander Archipelago , the many thousand islands of the British Columbia Coast, and Newfoundland. Greenland , a self-governing Danish island, and the world's largest , is on the same tectonic plate (the North American Plate ) and
15886-578: The continent. The vast majority of North America is on the North American Plate. Parts of western Mexico, including Baja California, and of California , including the cities of San Diego , Los Angeles , and Santa Cruz , lie on the eastern edge of the Pacific Plate , with the two plates meeting along the San Andreas Fault . The southernmost portion of the continent and much of the West Indies lie on
16055-654: The cordillera, while the major islands of Hawaii consist of Neogene volcanics erupted over a hot spot . Central America is geologically active with volcanic eruptions and earthquakes occurring from time to time. In 1976 Guatemala was hit by a major earthquake , killing 23,000 people; Managua, the capital of Nicaragua, was devastated by earthquakes in 1931 and 1972, the last one killing about 5,000 people; three earthquakes devastated El Salvador, one in 1986 and two in 2001; one earthquake devastated northern and central Costa Rica in 2009, killing at least 34 people; in Honduras
16224-669: The cultures of the region commonly reflect Western traditions . However, relatively small parts of North America in Canada, the United States, Mexico, and Central America have indigenous populations that continue adhering to their respective pre-European colonial cultural and linguistic traditions. The Americas were named after the Italian explorer Amerigo Vespucci by German cartographers Martin Waldseemüller and Matthias Ringmann . Vespucci explored South America between 1497 and 1502, and
16393-455: The discovery of a fossilized fungus, named Ourasphaira giraldae , in the Canadian Arctic , that may have grown on land a billion years ago, well before plants were living on land. Pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) have been reported in South China. Earlier, it had been presumed that the fungi colonized the land during
16562-602: The dominant life form at this time, representing nearly 100% of the available fossil record for this period. However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess, the spike did not appear worldwide, and in many places it did not fall on the Permian–Triassic boundary. Sixty-five million years ago, immediately after the Cretaceous–Paleogene extinction event that famously killed off most dinosaurs, there
16731-401: The dramatic up-regulation of particular gene transcriptions, constituting its biotrophy genomic features. These genomic regions have parallels in other eukaryotic plant pathogens. These parallels – between these independently evolved and unrelated sets of genes – show a strong and broad pattern of convergent evolution around the plant pathogenic lifestyle . Due to its cyclical nature, there
16900-447: The driest in the U.S. Highland climates cut from north to south of the continent, where subtropical or temperate climates occur just below the tropics, as in central Mexico and Guatemala . Tropical climates appear in the island regions and in the subcontinent's bottleneck, found in countries and states bathed by the Caribbean Sea or to the south of the Gulf of Mexico and the Pacific Ocean . Precipitation patterns vary across
17069-535: The early Devonian (416–359.2 Ma), when they occur abundantly in the Rhynie chert , mostly as Zygomycota and Chytridiomycota . At about this same time, approximately 400 Ma, the Ascomycota and Basidiomycota diverged, and all modern classes of fungi were present by the Late Carboniferous ( Pennsylvanian , 318.1–299 Ma). Lichens formed a component of the early terrestrial ecosystems, and
17238-412: The effects on growth rates are small, and the underlying biophysical and biochemical processes are not well known. This process might bear similarity to CO 2 fixation via visible light , but instead uses ionizing radiation as a source of energy. Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms. It is estimated that
17407-463: The end of the Canadian Shield, near the Great Lakes . Climate west of the Cascade Range is described as being temperate weather with average precipitation 20 inches (510 millimeters). Climate in coastal California is described to be Mediterranean , with average temperatures in cities like San Francisco ranging from 57 to 70 °F (14 to 21 °C) over the course of the year. Stretching from
17576-427: The environment to digest large organic molecules—such as polysaccharides , proteins , and lipids —into smaller molecules that may then be absorbed as nutrients. The vast majority of filamentous fungi grow in a polar fashion (extending in one direction) by elongation at the tip (apex) of the hypha. Other forms of fungal growth include intercalary extension (longitudinal expansion of hyphal compartments that are below
17745-522: The estimated age of the oldest terrestrial lichen fossil is 415 Ma; this date roughly corresponds to the age of the oldest known sporocarp fossil, a Paleopyrenomycites species found in the Rhynie Chert. The oldest fossil with microscopic features resembling modern-day basidiomycetes is Palaeoancistrus , found permineralized with a fern from the Pennsylvanian. Rare in the fossil record are
17914-544: The first American inhabitants sailed from Beringia some 13,000 years ago, with widespread habitation of the Americas during the end of the Last Glacial Period , in what is known as the Late Glacial Maximum , around 12,500 years ago. The oldest petroglyphs in North America date from 15,000 to 10,000 years before present. Genetic research and anthropology indicate additional waves of migration from Asia via
18083-540: The first barley stem rust to show up in the United States in 1991, in southern Texas in Uvalde . Thought to be responsible for rusting of wild Hordea in the Midwestern United States and Great Plains, and overall was 94% of Pg s on Hordea in 1991. 67% of QCCJ was from barley and 95% of Pg on barley was QCCJ. On wheat, QCCJ was still the most common race but only at 38% of Pg . Continues to threaten barley in
18252-446: The first week of June, and in west central Indiana , in 1991. TPMK was the worst at 69% of Pg s on wheat in 1997 in the United States – being absent only from the southern Great Plains and the west, but then was down to 10% in 1998. In the upper Great Plains it was already declining – to 26% of samples in 1997, and 12% in 1998. In the most fertile areas of the eastern US it was 96% of Pg s in 1997 but then suddenly fell to 29% in 1998. In
18421-535: The force of falling water drops to liberate the spores from cup-shaped fruiting bodies. Another strategy is seen in the stinkhorns , a group of fungi with lively colors and putrid odor that attract insects to disperse their spores. In homothallic sexual reproduction , two haploid nuclei derived from the same individual fuse to form a zygote that can then undergo meiosis . Homothallic fungi include species with an Aspergillus -like asexual stage (anamorphs) occurring in numerous different genera, several species of
18590-417: The formation of the hook ensures proper distribution of the newly divided nuclei into the apical and basal hyphal compartments. An ascus (plural asci ) is then formed, in which karyogamy (nuclear fusion) occurs. Asci are embedded in an ascocarp , or fruiting body. Karyogamy in the asci is followed immediately by meiosis and the production of ascospores . After dispersal, the ascospores may germinate and form
18759-414: The general public due to their historical classification, as well as several similarities. Like plants, fungi often grow in soil and, in the case of mushrooms , form conspicuous fruit bodies , which sometimes resemble plants such as mosses . The fungi are now considered a separate kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago (around
18928-843: The geographic center of either the 50 states, the conterminous United States, or the North American continent." Nonetheless, there is a 4.6-meter (15 ft) field stone obelisk in Rugby claiming to mark the center. The North American continental pole of inaccessibility is located 1,650 km (1,030 mi) from the nearest coastline, between Allen and Kyle, South Dakota at 43°22′N 101°58′W / 43.36°N 101.97°W / 43.36; -101.97 ( Pole of Inaccessibility North America ) . Canada can be divided into roughly seven physiographic divisions: The lower 48 U.S. states can be divided into roughly eight physiographic divisions: Mexico can be divided into roughly fifteen physiographic divisions: North America
19097-769: The higher taxonomic levels and there are frequent name changes at every level, from species upwards. Efforts among researchers are now underway to establish and encourage usage of a unified and more consistent nomenclature . Until relatively recent (2012) changes to the International Code of Nomenclature for algae, fungi and plants , fungal species could also have multiple scientific names depending on their life cycle and mode (sexual or asexual) of reproduction. Web sites such as Index Fungorum and MycoBank are officially recognized nomenclatural repositories and list current names of fungal species (with cross-references to older synonyms ). The 2007 classification of Kingdom Fungi
19266-408: The host cells to consume nutrients. Although fungi are opisthokonts —a grouping of evolutionarily related organisms broadly characterized by a single posterior flagellum —all phyla except for the chytrids have lost their posterior flagella. Fungi are unusual among the eukaryotes in having a cell wall that, in addition to glucans (e.g., β-1,3-glucan ) and other typical components, also contains
19435-411: The identification of species or groups. Some individual fungal colonies can reach extraordinary dimensions and ages as in the case of a clonal colony of Armillaria solidipes , which extends over an area of more than 900 ha (3.5 square miles), with an estimated age of nearly 9,000 years. The apothecium —a specialized structure important in sexual reproduction in the ascomycetes—is
19604-419: The indigenous people who lived there, including the bison hunters of the Great Plains and the farmers of Mesoamerica . Native groups also are classified by their language families , which included Athapascan and Uto-Aztecan languages. Indigenous peoples with similar languages did not always share the same material culture , however, and were not necessarily always allies. Anthropologists speculate that
19773-416: The intense UV and cosmic radiation encountered during space travel. Most grow in terrestrial environments, though several species live partly or solely in aquatic habitats, such as the chytrid fungi Batrachochytrium dendrobatidis and B. salamandrivorans , parasites that have been responsible for a worldwide decline in amphibian populations. These organisms spend part of their life cycle as
19942-460: The land since its creation, but there is no evidence that humans evolved there. The specifics of the initial settlement of the Americas by ancient Asians are subject to ongoing research and discussion. The traditional theory has been that hunters entered the Bering Land Bridge between eastern Siberia and present-day Alaska from 27,000 to 14,000 years ago. A growing viewpoint is that
20111-407: The leaf sheaths, but are also found on stems , leaves , glumes and awns . On leaves they develop mostly on the underside but may penetrate to the upperside. On leaf sheaths and glumes pustules rupture the epidermis, giving a ragged appearance. Towards the end of the growing season black telia are produced. For this reason stem rust is also known as "black rust". The telia are firmly attached to
20280-415: The leaf surface. So important is its role in maintenance of prevalence that since the near extermination of the alternate host from the northern Great Plains in the United States, epidemics in crops have become rare. Like other Puccinia species, P. graminis is an obligate biotroph (it colonizes living plant cells) and has a complex life cycle featuring alternation of generations . The fungus
20449-402: The leaf the mycelium produces specialised infection structures called pycnia. The pycnia produce two types of haploid gametes, the pycniospores and the receptive hyphae. The pycniospores are produced in a sticky honeydew that attracts insects. The insects carry pycniospores from one leaf to another. Splashing raindrops can also spread pycniospores. A pycniospore can fertilise a receptive hypha of
20618-401: The life cycle. Basidiospores are thin-walled and colourless. They cannot infect the cereal host, but can infect the alternative host (barberry). They are usually carried to the alternative host by wind. Once basidiospores arrive on a leaf of the alternative host, they germinate to produce a mycelium (which is haploid ) that directly penetrates the epidermis and colonises the leaf. Once inside
20787-640: The mainland in Mexico. With local indigenous allies, the Spanish conquered the Aztec empire in central Mexico in 1521. Spain then established permanent cities in Mexico, Central America, and Spanish South America in the sixteenth century. Once Spaniards conquered the high civilization of the Aztecs and Incas, the Caribbean was a backwater of the Spanish empire. Other European powers began to intrude on areas claimed by Spain, including
20956-912: The middle into the main range of the Rockies and the coast ranges in California , Oregon , Washington , and British Columbia , with the Great Basin—a lower area containing smaller ranges and low-lying deserts—in between. The highest peak is Denali in Alaska. The U.S. Geographical Survey (USGS) states that the geographic center of North America is "6 miles [10 km] west of Balta, Pierce County, North Dakota " at about 48°10′N 100°10′W / 48.167°N 100.167°W / 48.167; -100.167 , about 24 kilometers (15 mi) from Rugby, North Dakota . The USGS further states that "No marked or monumented point has been established by any government agency as
21125-427: The mycelia produce structures called telia. Telia produce a type of spore called teliospores . These black, thick-walled spores are dikaryotic . They are the only form in which Puccinia graminis is able to overwinter independently of a host. Each teliospore undergoes karyogamy (fusion of nuclei) and meiosis to form four haploid spores called basidiospores . This is an important source of genetic recombination in
21294-450: The name America to North America. In 1538, Gerardus Mercator used the term America on his world map of the entire Western Hemisphere . On his subsequent 1569 map , Mercator called North America "America or New India" ( America sive India Nova ). The Spanish Empire called its territories in North and South America "Las Indias", and the name given to the state body that oversaw the region
21463-607: The nature of fungal fruiting bodies , which are soft, fleshy, and easily degradable tissues, and the microscopic dimensions of most fungal structures, which therefore are not readily evident. Fungal fossils are difficult to distinguish from those of other microbes, and are most easily identified when they resemble extant fungi. Often recovered from a permineralized plant or animal host, these samples are typically studied by making thin-section preparations that can be examined with light microscopy or transmission electron microscopy . Researchers study compression fossils by dissolving
21632-493: The northernmost countries and territories of North America: the U.S., Bermuda , Canada, Greenland, and St. Pierre and Miquelon. Although the term does not refer to a unified region, Middle America includes Mexico, Central America, and the Caribbean. North America's largest countries by land area are Canada and the U.S., both of which have well-defined and recognized subregions. In Canada, these include (from east to west) Atlantic Canada , Central Canada , Canadian Prairies ,
21801-440: The northernmost extent of the island named Newfoundland , has provided unmistakable evidence of Norse settlement. Norse explorer Leif Erikson (c. 970–1020 CE) is thought to have visited the area. Erikson was the first European to make landfall on the continent (excluding Greenland). The Mayan culture was still present in southern Mexico and Guatemala when the Spanish conquistadors arrived, but political dominance in
21970-416: The only type of spores in the rust fungus life cycle that are capable of infecting the host on which they are produced, and this is therefore referred to as the 'repeating stage' of the life cycle. It is the spread of urediniospores that allows infection to spread from one cereal plant to another. This phase can rapidly spread the infection over a wide area. Towards the end of the cereal host's growing season,
22139-406: The opposite mating type , leading to the production of a mycelium that is dikaryotic . This is the sexual stage of the life cycle and cross-fertilisation provides an important source of genetic recombination. This dikaryotic mycelium then forms structures called aecia , which produce a type of dikaryotic spores called aeciospores . These have a worty appearance and are formed in chains – unlike
22308-401: The opposite mating type , whereas homothallic species can mate, and sexually reproduce, with any other individual or itself. Most fungi have both a haploid and a diploid stage in their life cycles. In sexually reproducing fungi, compatible individuals may combine by fusing their hyphae together into an interconnected network; this process, anastomosis , is required for the initiation of
22477-445: The phrase fauna and flora be replaced by fauna, flora, and funga . Before the introduction of molecular methods for phylogenetic analysis, taxonomists considered fungi to be members of the plant kingdom because of similarities in lifestyle: both fungi and plants are mainly immobile , and have similarities in general morphology and growth habitat. Although inaccurate, the common misconception that fungi are plants persists among
22646-468: The plant and fungal enzymes that make these compounds differ from each other in sequence and other characteristics, which indicates separate origins and convergent evolution of these enzymes in the fungi and plants. Fungi have a worldwide distribution, and grow in a wide range of habitats, including extreme environments such as deserts or areas with high salt concentrations or ionizing radiation , as well as in deep sea sediments. Some can survive
22815-428: The plant may die. Infection can reduce what is an apparently healthy crop about three weeks before harvest into a black tangle of broken stems and shriveled grains by harvest. Stem rust of cereals causes yield losses in several ways: Stem rust on wheat is characterized by the presence of uredinia on the plant, which are brick-red, elongated, blister-like pustules that are easily shaken off. They most frequently occur on
22984-492: The plant tissue. The site of infection is a visible symptom of the disease. Pycnia appear on barberry plants in the spring, usually in the upper leaf surfaces. They are often in small clusters and exude pycniospores in a sticky honeydew. Five to ten days later, cup-shaped structures filled with orange-yellow, powdery aeciospores break through the lower leaf surface. The aecial cups are yellow and sometimes elongate to extend up to 5 millimetres ( 13 ⁄ 64 in) from
23153-417: The plant. The fungus grows inside the plant as a dikaryotic mycelium. Within 1–2 weeks the mycelium produces uredinia and the cycle is complete. Since the urediniospores are produced on the cereal host and can infect the cereal host, it is possible for the infection to pass from one year's crop to the next without infecting the alternate host (barberry). For example, infected volunteer wheat plants can serve as
23322-461: The potential of the re-emergence of stem wheat rust in UK. The fungal ancestors of stem rust have infected grasses for millions of years and wheat crops for as long as they have been grown. According to Jim Peterson, professor of wheat breeding and genetics at Oregon State University , "Stem rust destroyed more than 20% of U.S. wheat crops several times between 1917 and 1935, and losses reached 9% twice in
23491-417: The preparation of leavened bread and fermented juices. Some of the oldest written records contain references to the destruction of crops that were probably caused by pathogenic fungi. Mycology became a systematic science after the development of the microscope in the 17th century. Although fungal spores were first observed by Giambattista della Porta in 1588, the seminal work in the development of mycology
23660-586: The raised but relatively flat plateau of the Canadian Shield in the northeast; and the varied eastern region, which includes the Appalachian Mountains, the coastal plain along the Atlantic seaboard, and the Florida peninsula. Mexico, with its long plateaus and cordilleras , falls largely in the western region, although the eastern coastal plain does extend south along the Gulf. The western mountains are split in
23829-500: The region, and as such rainforest , monsoon , and savanna types can be found, with rains and high temperatures throughout the year. Notable North American fauna include the bison , black bear , jaguar , cougar , prairie dog , turkey , pronghorn , raccoon , coyote , and monarch butterfly . Notable plants that were domesticated in North America include tobacco , maize , squash , tomato , sunflower , blueberry , avocado , cotton , chile pepper , and vanilla . Laurentia
23998-451: The researched species of fungi are transported by wind. Such species often produce dry or hydrophobic spores that do not absorb water and are readily scattered by raindrops, for example. In other species, both asexual and sexual spores or sporangiospores are often actively dispersed by forcible ejection from their reproductive structures. This ejection ensures exit of the spores from the reproductive structures as well as traveling through
24167-466: The resolution and added robustness to estimates of genetic diversity within various taxonomic groups. Mycology is the branch of biology concerned with the systematic study of fungi, including their genetic and biochemical properties, their taxonomy, and their use to humans as a source of medicine, food, and psychotropic substances consumed for religious purposes, as well as their dangers, such as poisoning or infection. The field of phytopathology ,
24336-432: The rest of the stages remained unknown. Anton de Bary later conducted experiments to observe the beliefs of European farmers regarding the relationship between the rust and barberry plants, and after connecting the basidiospores of the basidia stage to barberry, he also identified that the aeciospores in the aecia stage reinfect the wheat host. Upon de Bary's discovery of all five spore stages and their need for barberry as
24505-478: The results of the formation of Pangaea was the Appalachian Mountains , which formed some 480 mya, making it among the oldest mountain ranges in the world. When Pangaea began to rift around 200 mya, North America became part of Laurasia , before it separated from Eurasia as its own continent during the mid- Cretaceous period. The Rockies and other western mountain ranges began forming around this time from
24674-436: The rust variations have five spore stages and alternate between two hosts. Wheat is the primary host, and barberry is the alternate host. The rust is sometimes termed "red rust" or "red dust" owing to the spores on the leaf surfaces that range from orange to dark-red in color. Later, the spores change and become dark in color, which gives rise to another common name, "black rust". The North American race nomenclature system
24843-455: The scientific study of fungi. The Latin adjectival form of "mycology" ( mycologicæ ) appeared as early as 1796 in a book on the subject by Christiaan Hendrik Persoon . The word appeared in English as early as 1824 in a book by Robert Kaye Greville . In 1836 the English naturalist Miles Joseph Berkeley 's publication The English Flora of Sir James Edward Smith, Vol. 5. also refers to mycology as
25012-420: The sexual cycle. Many ascomycetes and basidiomycetes go through a dikaryotic stage, in which the nuclei inherited from the two parents do not combine immediately after cell fusion, but remain separate in the hyphal cells (see heterokaryosis ). In ascomycetes, dikaryotic hyphae of the hymenium (the spore-bearing tissue layer) form a characteristic hook (crozier) at the hyphal septum. During cell division ,
25181-508: The size and shape of spores or fruiting structures, has traditionally dominated fungal taxonomy. Species may also be distinguished by their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals, or their reaction to chemical tests . The biological species concept discriminates species based on their ability to mate . The application of molecular tools, such as DNA sequencing and phylogenetic analysis, to study diversity has greatly enhanced
25350-434: The small size of their structures, and their cryptic lifestyles in soil or on dead matter. Fungi include symbionts of plants, animals, or other fungi and also parasites . They may become noticeable when fruiting , either as mushrooms or as molds. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange in the environment. They have long been used as
25519-590: The start of the Neoproterozoic Era). Some morphological, biochemical, and genetic features are shared with other organisms, while others are unique to the fungi, clearly separating them from the other kingdoms: Shared features: Unique features: Most fungi lack an efficient system for the long-distance transport of water and nutrients, such as the xylem and phloem in many plants. To overcome this limitation, some fungi, such as Armillaria , form rhizomorphs , which resemble and perform functions similar to
25688-413: The stem rust. Thirty years later it received its name, Puccinia graminis , by Persoon , and in 1854 brothers Louis René and Charles Tulasne discovered the characteristic five-spore stage that is known in some stem rust species. The brothers were also able to make a connection between the red (urediniospore) and black (teliospore) spores as different stages within the life cycle of the same organism, but
25857-609: The structurally similar hook in the ascomycetes, the clamp connection in the basidiomycetes is required for controlled transfer of nuclei during cell division, to maintain the dikaryotic stage with two genetically different nuclei in each hyphal compartment. A basidiocarp is formed in which club-like structures known as basidia generate haploid basidiospores after karyogamy and meiosis. The most commonly known basidiocarps are mushrooms, but they may also take other forms (see Morphology section). In fungi formerly classified as Zygomycota , haploid hyphae of two individuals fuse, forming
26026-581: The study of fungi. A group of all the fungi present in a particular region is known as mycobiota (plural noun, no singular). The term mycota is often used for this purpose, but many authors use it as a synonym of Fungi. The word funga has been proposed as a less ambiguous term morphologically similar to fauna and flora . The Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN) in August 2021 asked that
26195-605: The study of plant diseases, is closely related because many plant pathogens are fungi. The use of fungi by humans dates back to prehistory; Ötzi the Iceman , a well-preserved mummy of a 5,300-year-old Neolithic man found frozen in the Austrian Alps, carried two species of polypore mushrooms that may have been used as tinder ( Fomes fomentarius ), or for medicinal purposes ( Piptoporus betulinus ). Ancient peoples have used fungi as food sources—often unknowingly—for millennia, in
26364-503: The surrounding matrix with acid and then using light or scanning electron microscopy to examine surface details. The earliest fossils possessing features typical of fungi date to the Paleoproterozoic era, some 2,400 million years ago ( Ma ); these multicellular benthic organisms had filamentous structures capable of anastomosis . Other studies (2009) estimate the arrival of fungal organisms at about 760–1060 Ma on
26533-415: The urediniospores that are spiny and are produced on individual stalks. The chains of aeciospores are surrounded by a bell-like enclosure of fungal cells. The aeciospores are able to germinate on the cereal host but not on the alternative host (they are produced on the alternative host, which is usually barberry). They are carried by wind to the cereal host where they germinate and the germ tubes penetrate into
26702-420: The way for DNA analysis to be incorporated into taxonomy, which has sometimes challenged the historical groupings based on morphology and other traits. Phylogenetic studies published in the first decade of the 21st century have helped reshape the classification within the fungi kingdom, which is divided into one subkingdom , seven phyla , and ten subphyla . The English word fungus is directly adopted from
26871-410: Was a dramatic increase in evidence of fungi; apparently the death of most plant and animal species led to a huge fungal bloom like "a massive compost heap". Although commonly included in botany curricula and textbooks, fungi are more closely related to animals than to plants and are placed with the animals in the monophyletic group of opisthokonts . Analyses using molecular phylogenetics support
27040-540: Was called the Council of the Indies . The United Nations and its statistics division recognize North America as including three regions: Northern America, Central America , and the Caribbean . "Northern America" is a distinct term from "North America", excluding Central America, which itself may or may not include Mexico . In the limited context of regional trade agreements, the term is used to reference three nations: Canada,
27209-506: Was detected in the northwest Great Plains in 1988, and by 1990 was over 90% of Pg s on barley in the United States. Also afflicted wheat until a mass switch away from vulnerable cultivars resulted in complete absence in 1997 or 1998. Barley virulence is temperature-sensitive: from 18–20 °C (64–68 °F) rpg4 and Rpg5 are highly effective, but above 27 °C (81 °F) they are ineffective. Not necessarily distinguishable from QCCJ, used synonymously by some practitioners. Found in
27378-440: Was discovered by K.C. Mehta. Since the 1950s, wheat strains bred to be resistant to stem rust have become available. Fungicides effective against stem rust are available as well. In 1999 a new virulent race of stem rust was identified against which most current wheat strains show no resistance. The race was named TTKSK (e.g. isolate Ug99 ). An epidemic of stem rust on wheat caused by race TTKSK spread across Africa , Asia and
27547-522: Was due to the fact that European farmers noticed a correlation between barberry and stem rust epidemics in wheat. The law banned the planting of barberry near wheat fields and was the first of its kind. The parasitic nature of stem rust was discovered in the 1700s. Two Italian scientists, Fontana and Tozzetti , first explained the stem rust fungus in wheat in 1767. Italian scientist Giuseppe Maria Giovene (1753–1837), in his work Lettera al dottor Cosimo Moschettini sulla ruggine , also thoroughly studied
27716-458: Was estimated as over 592 million people in 23 independent states , or about 7.5% of the world's population. In human geography , the terms "North America" and "North American" can refer to Canada, the United States, Mexico, and Greenland or, alternatively, Canada, Greenland and the US (Mexico being classified as part of Latin America ) or simply Canada and the US (Greenland being classified as either Arctic or European (due to its political status as
27885-467: Was expected to thereafter be a permanent part of the North American Pg population. Further pathogen adaptation, resulting in widening of the host range, is expected. Synonymous with QCCJB or known as QCC-2 by some classifications. Most common Pg race in 1991 in the United States , 68% of all Pg samples, and 67% in 1990. Afflicted spring-sown barley in the northern Great Plains in 1990. Was
28054-790: Was in Jamestown, Virginia in 1607, followed by additional colonial establishments on the east coast from present-day Georgia in the south to Massachusetts in the north, forming the Thirteen Colonies of British America. The English did not establish settlements north or east of the St. Lawrence Valley in present-day Canada until after the conclusion of the American Revolutionary War . Britain's early settlements in present-day Canada included St. John's, Newfoundland in 1630 and Halifax, Nova Scotia in 1749. The first permanent French settlement
28223-415: Was introduced in 1988 by Roelfs and Martens. This nomenclature is a series of letters each of which indicate virulence/avirulence against one resistance gene , as diagnosed by performance against a group of cultivars known to bear that gene. Pgt contains many races of wheat diseases, including some of the most significant in the world. Ug99 began as a race ( TTKSK ) of Pgt and now has proliferated into
28392-412: Was partly prompted by the threat it posed to food supplies during World War I . The "war against barberries" was waged and called upon the help of citizens through radio and newspaper advertisements, pamphlets, and fair booths asking for help from all in the attempt to rid the barberry bushes of their existence. Later, in 1975–1980, the program was reestablished under state jurisdiction. Once this happened,
28561-468: Was the first European to suggest that the Americas represented a landmass not then known to the Europeans. In 1507, Waldseemüller published a world map, and placed the word "America" on the continent of present-day South America. The continent north of present-day Mexico was then referred to as Parias. On a 1553 world map published by Petrus Apianus , North America was called "Baccalearum", meaning "realm of
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