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''Amanita bisporigera'' is a deadly poisonous species of fungus in the Amanitaceae family. It is commonly known as the eastern North American destroying angel or the destroying angel, although it shares this latter name with three other lethal white ''Amanita'' species, ''A. ocreata'', ''A. verna'' and ''A. virosa''. The fruit bodies are found on the ground in mixed coniferous and deciduous forests of Eastern North America south to Mexico, but are rare in western North America; it has also been found in pine plantations in Colombia. The mushroom has a smooth white cap that can reach up to across, and a stem, up to long by thick, that has a delicate white skirt-like ring near the top. The bulbous stem base is covered with a membranous sac-like volva. The white gills are free from attachment to the stalk and crowded closely together. As the species name suggests, ''A. bisporigera'' typically bears two spores on the basidia, although this characteristic is not as immutable as was once thought. First described in 1906, ''A. bisporigera'' is classified in the section ''Phalloideae'' of the genus ''Amanita'' together with other amatoxin-containing species. Amatoxins are cyclic peptides which inhibit the enzyme RNA polymerase II and interfere with various cellular functions. The first symptoms of poisoning appear 6 to 24 hours after consumption, followed by a period of apparent improvement, then by symptoms of liver and kidney failure, and death after four days or more. ''Amanita bisporigera'' closely resembles a few other white amanitas, including the equally deadly ''A. virosa'' and ''A. verna''. These species, difficult to distinguish from ''A. bisporigera'' based on visible field characteristics, do not have two-spored basidia, and do not stain yellow when a dilute solution of potassium hydroxide is applied. The DNA of ''A. bisporigera'' has been partially sequenced, and the genes responsible for the production of amatoxins have been determined. ==Taxonomy, classification, and phylogeny== |2=''A. bisporigera'' }} |2=''A. fuliginea'' }} |2=''A. hemibapha'' }} }} }} | caption=Relationships of ''Amanita bisporigera'' and related species based on ITS sequence data. The ''A. virosa'' specimen was collected from Japan, ''A. bisporigera'' from the USA, and the other species from China.〔 }} ''Amanita bisporigera'' was first described scientifically in 1906 by American botanist George Francis Atkinson in a publication by Cornell University colleague Charles E. Lewis. The type locality was Ithaca, New York, where several collections were made.〔 In his 1941 monograph of world ''Amanita'' species, Jean-Edouard Gilbert transferred the species to his new genus ''Amanitina'',〔 but this genus is now considered synonymous with ''Amanita''.〔 In 1944, William Murrill described the species ''Amanita vernella'', collected from Gainesville, Florida;〔 that species is now thought to be synonymous with ''A. bisporigera'' after a 1979 examination of its type material revealed basidia that were mostly 2-spored.〔〔 ''Amanita phalloides'' var. ''striatula'', a poorly known taxon originally described from the United States in 1902 by Charles Horton Peck,〔 is considered by ''Amanita'' authority Rodham Tulloss to be synonymous with ''A. bisporigera''.〔 Vernacular names for the mushroom include "destroying angel", "deadly amanita", "white death cap", "angel of death"〔 and "eastern North American destroying angel".〔 ''Amanita bisporigera'' belongs to section ''Phalloideae'' of the genus ''Amanita'', which contains some of the deadliest ''Amanita'' species, including ''A. phalloides'' and ''A. virosa''. This classification has been upheld with phylogenetic analyses, which demonstrate that the toxin-producing members of section ''Phalloideae'' form a clade—that is, they derive from a common ancestor.〔〔 In 2005, Zhang and colleagues performed a phylogenetic analysis based on the internal transcribed spacer (ITS) sequences of several white-bodied toxic ''Amanita'' species, most of which are found in Asia. Their results support a clade containing ''A. bisporigera'', ''A. subjunquillea'' var. ''alba'', ''A. exitialis'', and ''A. virosa''. The Guangzhou destroying angel (''Amanita exitialis'') has two-spored basidia, like ''A. bisporigera''.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Amanita bisporigera」の詳細全文を読む スポンサード リンク
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