''Amanita cokeri'', commonly known as Coker's amanita and solitary lepidella, is a

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...

in the family

Amanitaceae The Amanitaceae is a family of mushroom-forming fungi. ''Amanita'' Pers. is one of the most specious and best-known fungal genera. The family, also commonly called the amanita family, is in order Agaricales, the gilled mushrooms. The family c ...

. The mushroom is

poisonous Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

. First described as ''Lepidella cokeri'' in 1928, it was transferred to the genus ''

Amanita The genus ''Amanita'' contains about 600 species of agarics, including some of the most toxic known mushrooms found worldwide, as well as some well-regarded edible species. This genus is responsible for approximately 95% of the fatalities resul ...

'' in 1940.

Taxonomy

''Amanita cokeri'' was first described as ''Lepidella cokeri'' by mycologists E.-J.Gilbert and Robert Kühner in 1928. It was in 1940 when the species was transferred from genus ''Lepidella'' to ''

'' by Gilbert. Presently, ''A. cokeri'' is placed under genus ''

'' and section ''Roanokenses''. The epithet ''cokeri'' is in honour of American mycologist and botanist

William Chambers Coker William Chambers Coker (October 24, 1872 – June 26, 1953) was an American botany, botanist and mycology, mycologist. Biography He was born at Hartsville, South Carolina on October 24, 1872. He graduated from University of South Carolina, Sou ...

Description

Its

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

is white in colour, and across. It is oval to convex in shape. The surface is dry but sticky when wet. The cap surface is characterized by large pointed warts, white to brown in colour.

Gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s are closely spaced and free from the stem. They are cream at first, but can turn white as the mushroom matures. Short-gills are frequent. Stem is white, measuring long and thick. It tapers slightly to the top, smooth to shaggy in texture. There is a ring, thick and often double-edged, the underside being tissuelike. The universal veil hangs from the top of the stipe. The basal bulb is considerably large in size, with concentric circles of down-turned scales. The volval remnants stick to it and cause irregular patches. Spores are white, elliptical and

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of 7–13 nm in diameter, a beta sheet (β-sheet) secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the huma ...

. They measure 11-14 x 6-9 μm, and feel smooth.

Flesh Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscles, fats and other loose connective tissues, but ...

is white, and shows no change when exposed. There is no distinctive odour, but some specimens may develop the smell of decaying protein.

Lookalikes

'' Amanita solitaria'' is a closely related species, though a completely different European taxa. The notable similarity is that both it and ''A. cokeri'' are double-ringed. '' A. timida'', from the tropical South Asia, resembles ''A. cokeri'' in its volval structure, thick and notable ring and the large bulbal base.

Toxicity

In a study, the presence of non-protein

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

s 2-amino-3-cyclopropylbutanoic acid and 2-amino-5-chloro-4-pentenoic acid was revealed. The former acid was found to be toxic to the fungus '' Cercospora kikuchii'', the arthropod ''

Oncopeltus fasciatus ''Oncopeltus fasciatus'', known as the large milkweed bug, is a medium-sized hemipteran (true bug) of the family Lygaeidae.Attisano, A. (2013) Oosorption and migratory strategy of the milkweed bug,''Oncopeltus fasciatus. Animal Behaviour 86(3):65 ...

'' and the bacteria '' Agrobacterium tumefaciens'', ''

Erwinia amylovora Fire blight, also written fireblight, is a contagious disease affecting apples, pears, and some other members of the family Rosaceae. It is a serious concern to apple and pear producers. Under optimal conditions, it can destroy an entire orchard ...

'', and ''

Xanthomonas campestris ''Xanthomonas campestris'' is a bacterium that causes a variety of plant diseases, including "black rot" in cruciferous vegetables and bacterial wilt of turfgrass. It is also used in the commercial production of xanthan gum, a high-molecular-we ...

''. The toxicity for bacteria could be eliminated by adding isoleucine to the medium. The other acid did not prove toxic.

Habitat and distribution

''Amanita cokeri'' inhabits mixed coniferous or deciduous woods and also grows on the ground. It grows mainly on oak and pine trees, and leaves a white deposit. It grows isolated or in groups. It is mostly distributed in southeastern North America. It fruits from July to November.

References

External links

{{Taxonbar, from=Q1951851 cokeri Poisonous fungi Fungi described in 1928 Fungi of North America