Amanita aestivalis
Encyclopedia
Amanita aestivalis, commonly
known as the white American star-footed Amanita, is a species of fungus
in the Amanitaceae
family of mushroom
s. The fungus is distributed in the eastern United States, south to Florida
, and reaches north into the southeastern provinces of Canada. The cap
of the fruit body
is medium-sized, 5 to 8.5 cm (2 to 3.3 in) in diameter and white. It sits atop a stem
that is 8.5 to 16 cm (3.3 to 6.3 in) long and has a rounded bulb its the base. The entire fruit body will slowly stain a reddish-brown color in response to bruising or aging. It remains unknown whether Amanita aestivalis is a distinct species from A. brunnescens
, another similar Amanita
with a comparable distribution. There are several other white-bodied amanitas with which A. aestivalis may be confused, including A. virosa
, A. phalloides, and A. bisporigera
.
first described the species in 1949 based on specimens he had collected in Massachusetts
, Michigan
, New York and Virginia
. Because this original report was published without a Latin
description (contrary to the naming conventions of the International Code of Botanical Nomenclature), he later amended his description in 1959. There is some doubt as to whether A. aestivalis is a distinct species from A. brunnescens
(the "brown American star-footed Amanita"), as described by George F. Atkinson in 1918. Singer claimed that the latter species could be distinguished from the former by the consistent absence of dusky brownish-gray radial stripes on the cap. However, in 1927, mycologist Louis Charles Christopher Krieger described the variant A. brunnescens var. pallida, which he said was identical to A. brunnescens except for the white or very pale cap. In his 1986 monograph
on North American species of Amanita, David T. Jenkins preferred to reserve judgment on the matter.
Amanita aestivalis is classified
in the section Vallidae of the genus Amanita, a grouping of amanitas characterized by having spherical spores, well-developed rings
, weakly reddening flesh, and "limbate" volvals (with narrow "limbs" protruding from a soft, margined bulb).
The specific epithet is derived from the Latin
adjective aestivalis, meaning "pertaining to the summer". Its vernacular name
is the "white American star-footed Amanita".
of the fruit body
is 5 to 8.5 cm (2 to 3.3 in) in diameter, and depending on its age, may range from egg-shaped to convex to somewhat flattened. Older specimens may have edges that are curved upwards. The color is white or pale tan in the center of the cap; older specimens may have areas of discolored tissue colored brownish-red shades. Sometimes, the edge of the cap has radial grooves—up to 4 mm (0.15748031496063 in) long—that mirror the position of the underlying gills. When moist, the cap is sticky to the touch; when dry, it is shiny, usually without any remnants of the thin volva. The white gills are crowded close together, and are free from attachment to the stem. They are subventricose: slightly swollen in the middle, and tapering near the ends.
The stem
is 8.5 to 16 cm (3.3 to 6.3 in) long by 0.9 to 1.6 cm (0.354330708661417 to 0.62992125984252 in) thick, and slightly thicker at the base than at the top. It is stuffed with whitish hypha
e that resemble cotton. The surface of the stem is smooth or has delicate tufts of soft, white, woolly hairs. There is a rimmed bulb at the base of the stem, which can reach a diameter of over 3 cm (1.2 in). The ring
—located on the upper portion of the stem, 1.2–1.7 cm (0.47244094488189–0.669291338582677 in) from the top—is white, membranous, and long-lasting. The volva
remains closely attached to the bulb, although a portion may stretch out like a thin membrane and adhere to the base of the stem before collapsing. The flesh
will slowly turn pinkish-brown to chocolate-brown when it has been injured or bruised. Young specimens do not have any distinct odor, but fruit bodies may smell slightly of onions or garlic in age.
Although the edibility
has not been documented for this species, some sources have noted that toxicity is suspected.
, the basidiospores of A. aestivalis are white. Examination with a microscope reveals further details: they are roughly spherical, hyaline
(translucent) and thin-walled, with dimensions of 7.8–8.8 µm
. The spores are amyloid
, meaning that they will absorb iodine
when stained with Melzer's reagent
and appear blue to blackish-blue. The spore-bearing cells, the basidia, are four-spored, thin-walled, and measure 32–60 long by 4–13 µm thick. There are no clamps present at the bases of the basidia.
in the eastern United States. A. verna, however, has ellipsoid spores. Other white amanitas within the range of A. aestivalis include the deadly toxic species A. virosa
(has a more loose cottony stem), A. phalloides (the cap usually has an olive-green tint) and A. bisporigera
(typically has two-spored basidia). A. aestivalis is sometimes considered a white form of A. brunnescens
, but this latter species has dusky brownish gray radial stripes and usually has many fibrils (short section of hypha
e) projecting from the surface, to produce a fine, hairy appearance. Further, it stains more rapidly than A. aestivalis. A. asteropus (the "European star-footed Amanita") is cream to yellow color, and differs from A. aestivalis in its reaction to chemical tests
. It is only known from Europe.
l species, meaning it forms a mutualistic relationship in which the vegetative
hypha
e of the fungus grow around and enclose the tiny roots of trees and shrubs. In this way, the plant is better able to absorb phosphorus
and other soil nutrients, while the fungus receives moisture, protection, and nutritive byproducts of the plant's metabolism. Fruit bodies of the fungus grow on the ground in deciduous
, coniferous, and mixed forests
. A preference has been noted for oak woods containing Tsuga
or Pinus species, as well as beech wood with Picea, Abies, and Betula. Fruit bodies typically appear from late June until autumn. In North America, it has been found in the states of New England
, as well as Alabama
, New York, and Virginia
. The distribution extends north to the southeastern provinces of Canada and south to Florida
.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
known as the white American star-footed Amanita, is a species of fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
in the Amanitaceae
Amanitaceae
Amanitaceae are a family of fungi or mushrooms. The family, also commonly called the Amanita family, is in order Agaricales, gilled mushrooms...
family of mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
s. The fungus is distributed in the eastern United States, south to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and reaches north into the southeastern provinces of Canada. The cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
of the fruit body
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
is medium-sized, 5 to 8.5 cm (2 to 3.3 in) in diameter and white. It sits atop a stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
that is 8.5 to 16 cm (3.3 to 6.3 in) long and has a rounded bulb its the base. The entire fruit body will slowly stain a reddish-brown color in response to bruising or aging. It remains unknown whether Amanita aestivalis is a distinct species from A. brunnescens
Amanita brunnescens
Amanita brunnescens, also known as the brown American star-footed amanita or cleft-footed amanita is a native North American mushroom of the large genus Amanita. Originally presumed to be Amanita phalloides by renowned American mycologist Charles Horton Peck it was described and named by G. F....
, another similar Amanita
Amanita
The genus Amanita contains about 600 species of agarics including some of the most toxic known mushrooms found worldwide. This genus is responsible for approximately 95% of the fatalities resulting from mushroom poisoning, with the death cap accounting for about 50% on its own...
with a comparable distribution. There are several other white-bodied amanitas with which A. aestivalis may be confused, including A. virosa
Amanita virosa
Amanita virosa, commonly known as the European destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees...
, A. phalloides, and A. bisporigera
Amanita bisporigera
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...
.
Taxonomy, classification, and naming
American mycologist Rolf SingerRolf Singer
Rolf Singer was a German-born mycologist and one of the most important taxonomists of gilled mushrooms in the 20th century....
first described the species in 1949 based on specimens he had collected in Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, New York and Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
. Because this original report was published without a Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
description (contrary to the naming conventions of the International Code of Botanical Nomenclature), he later amended his description in 1959. There is some doubt as to whether A. aestivalis is a distinct species from A. brunnescens
Amanita brunnescens
Amanita brunnescens, also known as the brown American star-footed amanita or cleft-footed amanita is a native North American mushroom of the large genus Amanita. Originally presumed to be Amanita phalloides by renowned American mycologist Charles Horton Peck it was described and named by G. F....
(the "brown American star-footed Amanita"), as described by George F. Atkinson in 1918. Singer claimed that the latter species could be distinguished from the former by the consistent absence of dusky brownish-gray radial stripes on the cap. However, in 1927, mycologist Louis Charles Christopher Krieger described the variant A. brunnescens var. pallida, which he said was identical to A. brunnescens except for the white or very pale cap. In his 1986 monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
on North American species of Amanita, David T. Jenkins preferred to reserve judgment on the matter.
Amanita aestivalis is classified
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
in the section Vallidae of the genus Amanita, a grouping of amanitas characterized by having spherical spores, well-developed rings
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
, weakly reddening flesh, and "limbate" volvals (with narrow "limbs" protruding from a soft, margined bulb).
The specific epithet is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
adjective aestivalis, meaning "pertaining to the summer". Its vernacular name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
is the "white American star-footed Amanita".
Description
The capPileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
of the fruit body
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
is 5 to 8.5 cm (2 to 3.3 in) in diameter, and depending on its age, may range from egg-shaped to convex to somewhat flattened. Older specimens may have edges that are curved upwards. The color is white or pale tan in the center of the cap; older specimens may have areas of discolored tissue colored brownish-red shades. Sometimes, the edge of the cap has radial grooves—up to 4 mm (0.15748031496063 in) long—that mirror the position of the underlying gills. When moist, the cap is sticky to the touch; when dry, it is shiny, usually without any remnants of the thin volva. The white gills are crowded close together, and are free from attachment to the stem. They are subventricose: slightly swollen in the middle, and tapering near the ends.
The stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
is 8.5 to 16 cm (3.3 to 6.3 in) long by 0.9 to 1.6 cm (0.354330708661417 to 0.62992125984252 in) thick, and slightly thicker at the base than at the top. It is stuffed with whitish hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e that resemble cotton. The surface of the stem is smooth or has delicate tufts of soft, white, woolly hairs. There is a rimmed bulb at the base of the stem, which can reach a diameter of over 3 cm (1.2 in). The ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
—located on the upper portion of the stem, 1.2–1.7 cm (0.47244094488189–0.669291338582677 in) from the top—is white, membranous, and long-lasting. The volva
Volva (mycology)
The volva is a mycological term to describe a cup-like structure at the base of a mushroom that is a remnant of the universal veil. This macrofeature is important in wild mushroom identification due to it being an easily observed, taxonomically significant feature which frequently signifies a...
remains closely attached to the bulb, although a portion may stretch out like a thin membrane and adhere to the base of the stem before collapsing. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
will slowly turn pinkish-brown to chocolate-brown when it has been injured or bruised. Young specimens do not have any distinct odor, but fruit bodies may smell slightly of onions or garlic in age.
Although the edibility
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
has not been documented for this species, some sources have noted that toxicity is suspected.
Microscopic characteristics
Viewed in deposit, like with a spore printSpore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...
, the basidiospores of A. aestivalis are white. Examination with a microscope reveals further details: they are roughly spherical, hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
(translucent) and thin-walled, with dimensions of 7.8–8.8 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
. The spores are amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
, meaning that they will absorb iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
when stained with Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
and appear blue to blackish-blue. The spore-bearing cells, the basidia, are four-spored, thin-walled, and measure 32–60 long by 4–13 µm thick. There are no clamps present at the bases of the basidia.
Similar species
According to Singer, the species is often mistaken for A. vernaAmanita verna
Amanita verna, commonly known as the fool's mushroom, Destroying angel or the mushroom fool, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe in spring, A. verna associates with various deciduous and coniferous trees...
in the eastern United States. A. verna, however, has ellipsoid spores. Other white amanitas within the range of A. aestivalis include the deadly toxic species A. virosa
Amanita virosa
Amanita virosa, commonly known as the European destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees...
(has a more loose cottony stem), A. phalloides (the cap usually has an olive-green tint) and A. bisporigera
Amanita bisporigera
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...
(typically has two-spored basidia). A. aestivalis is sometimes considered a white form of A. brunnescens
Amanita brunnescens
Amanita brunnescens, also known as the brown American star-footed amanita or cleft-footed amanita is a native North American mushroom of the large genus Amanita. Originally presumed to be Amanita phalloides by renowned American mycologist Charles Horton Peck it was described and named by G. F....
, but this latter species has dusky brownish gray radial stripes and usually has many fibrils (short section of hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e) projecting from the surface, to produce a fine, hairy appearance. Further, it stains more rapidly than A. aestivalis. A. asteropus (the "European star-footed Amanita") is cream to yellow color, and differs from A. aestivalis in its reaction to chemical tests
Chemical tests in mushroom identification
Chemical tests in mushroom identification are methods that aid in determining the variety of some fungi. The most useful tests are Melzer's reagent and potassium hydroxide.- Ammonia :Household ammonia can be used. A couple of drops are placed on the flesh...
. It is only known from Europe.
Habitat, distribution, and ecology
Amanita aestivalis is a mycorrhizaMycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....
l species, meaning it forms a mutualistic relationship in which the vegetative
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e of the fungus grow around and enclose the tiny roots of trees and shrubs. In this way, the plant is better able to absorb phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
and other soil nutrients, while the fungus receives moisture, protection, and nutritive byproducts of the plant's metabolism. Fruit bodies of the fungus grow on the ground in deciduous
Temperate deciduous forest
A temperate deciduous forest, more precisely termed temperate broadleaf forest or temperate broadleaved forest, is a biome found in North America, southern South America, Europe, and Asia. A temperate deciduous forest consists of trees that lose their leaves every year...
, coniferous, and mixed forests
Temperate broadleaf and mixed forests
Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...
. A preference has been noted for oak woods containing Tsuga
Tsuga
Tsuga is a genus of conifers in the family Pinaceae. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock....
or Pinus species, as well as beech wood with Picea, Abies, and Betula. Fruit bodies typically appear from late June until autumn. In North America, it has been found in the states of New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
, as well as Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, New York, and Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
. The distribution extends north to the southeastern provinces of Canada and south to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
.