Amanita onusta
Encyclopedia
Amanita onusta, commonly
known as the loaded Lepidella or the gunpowder Lepidella, is a species of fungus
in the Amanitaceae
family of mushroom
s. It is characterized by its small to medium-sized fruit bodies
that have white to pale gray caps
crowded with roughly conical, pyramidal, or irregular gray warts. The stem
is whitish-gray with woolly or wart-like veil
remnants, and at the base is a spindle- or turnip-shaped base that is rooted somewhat deeply in the soil. The species is distributed in eastern North America, from Nova Scotia
to Mexico, and may be found growing on the ground in deciduous forests, particularly those with oak
, hickory
and chestnut
. Fruit bodies smell somewhat like bleaching powder, and their edibility is unknown, but possibly toxic.
transferred the species to the genus Amanita
. Amanita authority Cornelis Bas, writing in his extensive 1969 monograph
on the genus, placed the species in his stirps Microlepis, subsection Solitariae, section
Lepidellus. This grouping of Amanita mushroom species also includes A. abrupta
, A. atkinsoniana
, A. costaricensis (a provisionally named species authored by Tulloss, Halling, & G.M. Muell.), A. nitida (as Coker described the species) and A. sphaerobulbosa.
The Latin
epithet onustusa means "charged, load-carrying, burdened", and a regular adjective derived from onus, "burden" (the same word that gave the English onus). A. onusta is commonly
known as the "loaded Lepidella", or the "gunpowder Lepidella".
of Amanita onusta have caps
that are initially broadly convex but flatten out as they mature, reaching diameters of 5 to 10 cm (2 to 3.9 in). The cap surface, grayish-white in color, is ornamented with conical or pyramidal raised warts, or flattened, symmetrically arranged gray to brownish gray, grayish brown or grayish-orange small scales (squamules) that are densely arranged over the surface.The squamules are less crowded near the edge of the cap (the margin). The margin does not have striations, and is typically fringed with remnants of the veil
. The gills on the underside of the cap are spaced closely together, and either free or narrowly attached to the stem. They are white to cream
color, and are interspersed with short lamellulae (gills that do not extend completely from cap margin to stem). The gills may look as if they are waterlogged.
The stem
is 5.5 to 12 cm (2.2 to 4.7 in) long, 0.6 to 1.5 cm (0.236220472440945 to 0.590551181102362 in) thick, and tapers slightly upwards. It is solid gray to brownish-gray near base, paler towards the top, and appears cottony (floccose) or hairy (fibrillose). The bulb at the base of the stem is roughly spindle- to turnip-shaped, and may root deeply into the soil, especially if the soil is loose. The short-lived partial veil
is white, and attached just below the top of the stem. It is sticky and in maturity often clings to the upper part of the stem, or may have some meagre remnants hanging from the cap margin. The universal veil
remains are arranged in rows of warts and patches of gray to brownish-gray small scales over the upper portion of the bulb; below this, the color is a dirty white. The flesh
is firm and white. Fruit bodies can range in smell from mild to "slightly unpleasant". The odor has been described as resembling "chloride of lime", a smell similar to some bathroom disinfectants containing bleach.
, the spores
are white. Viewed with a microscope, the spores are broadly ellipsoid to elongate, transclucent
, thin-walled, amyloid
, and have dimensions of 8.3–11.6 by 4.9–6.6 µm. The basidia (spore-bearing cells) are 38–46 by 9–11 µm
, club-shaped, mostly 4-spored but some are 2- or 3- spored, with clamps. The cheilocystidia (cystidia found on the edge of a gill) are 23.3–31.5 by 11.6–15.7 µm, ellipsoid, club- to pear-shaped cells, partly in short rows. The cap cuticle
is up to 168 µm thick, and consists of thin-walled interwoven hypha
e that are 2–5.3 µm diameter, and gelatinized. Clamp connection
s are present in the hyphae of this species—these are short branches connecting one cell to the previous cell to allow passage of the products of nuclear division.
species in that genus.
, its powdery-wooly to powdery-warty cap, as well as the absence of warts or scales at the base of the stem. A. cinereoconia also smells distinctly of chloride of lime. Another similar species is A. costaricensis, found only in Costa Rica. A. atkinsoniana, another North American species, has shorter warts that are spaced further apart than those of A. onusta, and the warts on the basal bulb are arranged in parallel rows.
, hickory
and chestnut
forests from southern New England
to Texas
. The species has a preference for sandy or loose soils. Its range extends north to Nova Scotia, Canada, and south to Mexico.
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 loaded Lepidella or the gunpowder Lepidella, 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. It is characterized by its small to medium-sized fruit bodies
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...
that have white to pale gray caps
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...
crowded with roughly conical, pyramidal, or irregular gray warts. 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 whitish-gray with woolly or wart-like veil
Universal veil
In mycology, a universal veil is a temporary membranous tissue that fully envelops immature fruiting bodies of certain gilled mushrooms. The developing Caesar's mushroom , for example, which may resemble a small white sphere at this point, is protected by this structure...
remnants, and at the base is a spindle- or turnip-shaped base that is rooted somewhat deeply in the soil. The species is distributed in eastern North America, from Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
to Mexico, and may be found growing on the ground in deciduous forests, particularly those with oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, hickory
Hickory
Trees in the genus Carya are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts...
and chestnut
Chestnut
Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...
. Fruit bodies smell somewhat like bleaching powder, and their edibility is unknown, but possibly toxic.
Taxonomy
Amanita onusta was first described in 1874 by American mycologist Elliot Calvin Howe as Agaricus onustus. Later, in 1891, Pier Andrea SaccardoPier Andrea Saccardo
Pier Andrea Saccardo was an Italian botanist and mycologist.- Life :...
transferred the species to the genus 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...
. Amanita authority Cornelis Bas, writing in his extensive 1969 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 the genus, placed the species in his stirps Microlepis, subsection Solitariae, section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...
Lepidellus. This grouping of Amanita mushroom species also includes A. abrupta
Amanita abrupta
Amanita abrupta, commonly known as the abrupt-bulbed Lepidella, is a species of fungus in the Amanitaceae family of mushrooms. Named for the characteristic shape of its fruit bodies, this white Amanita has a slender stem, a cap covered with conical white warts, and an "abruptly enlarged" swollen base...
, A. atkinsoniana
Amanita atkinsoniana
Amanita atkinsoniana is a species of fungus in the Amanitaceae family. It is found in the northeastern, southeastern, and southern United States as well as southern Canada, where it grows solitarily or in small groups on the ground in mixed woods. The fruit body is white to brownish, with caps that...
, A. costaricensis (a provisionally named species authored by Tulloss, Halling, & G.M. Muell.), A. nitida (as Coker described the species) and A. sphaerobulbosa.
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...
epithet onustusa means "charged, load-carrying, burdened", and a regular adjective derived from onus, "burden" (the same word that gave the English onus). A. onusta is commonly
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 "loaded Lepidella", or the "gunpowder Lepidella".
Description
The fruit bodiesBasidiocarp
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...
of Amanita onusta have caps
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...
that are initially broadly convex but flatten out as they mature, reaching diameters of 5 to 10 cm (2 to 3.9 in). The cap surface, grayish-white in color, is ornamented with conical or pyramidal raised warts, or flattened, symmetrically arranged gray to brownish gray, grayish brown or grayish-orange small scales (squamules) that are densely arranged over the surface.The squamules are less crowded near the edge of the cap (the margin). The margin does not have striations, and is typically fringed with remnants of the veil
Partial veil
thumb|150px|right|Developmental stages of [[Agaricus campestris]] showing the role and evolution of a partial veilPartial veil is a mycological term used to describe a temporary structure of tissue found on the fruiting bodies of some basidiomycete fungi, typically agarics...
. The gills on the underside of the cap are spaced closely together, and either free or narrowly attached to the stem. They are white to cream
Cream (colour)
Cream is the colour of the cream produced by cattle grazing on natural pasture with plants rich in yellow carotenoid pigments, some of which are incorporated into the cream, to give a yellow tone to white. Cream is the pastel colour of yellow, much like as pink is to red. Cream is used as a skin...
color, and are interspersed with short lamellulae (gills that do not extend completely from cap margin to stem). The gills may look as if they are waterlogged.
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 5.5 to 12 cm (2.2 to 4.7 in) long, 0.6 to 1.5 cm (0.236220472440945 to 0.590551181102362 in) thick, and tapers slightly upwards. It is solid gray to brownish-gray near base, paler towards the top, and appears cottony (floccose) or hairy (fibrillose). The bulb at the base of the stem is roughly spindle- to turnip-shaped, and may root deeply into the soil, especially if the soil is loose. The short-lived partial veil
Partial veil
thumb|150px|right|Developmental stages of [[Agaricus campestris]] showing the role and evolution of a partial veilPartial veil is a mycological term used to describe a temporary structure of tissue found on the fruiting bodies of some basidiomycete fungi, typically agarics...
is white, and attached just below the top of the stem. It is sticky and in maturity often clings to the upper part of the stem, or may have some meagre remnants hanging from the cap margin. The universal veil
Universal veil
In mycology, a universal veil is a temporary membranous tissue that fully envelops immature fruiting bodies of certain gilled mushrooms. The developing Caesar's mushroom , for example, which may resemble a small white sphere at this point, is protected by this structure...
remains are arranged in rows of warts and patches of gray to brownish-gray small scales over the upper portion of the bulb; below this, the color is a dirty white. 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....
is firm and white. Fruit bodies can range in smell from mild to "slightly unpleasant". The odor has been described as resembling "chloride of lime", a smell similar to some bathroom disinfectants containing bleach.
Microscopic characteristics
Viewed in deposit, such as 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 spores
Basidiospore
A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...
are white. Viewed with a microscope, the spores are broadly ellipsoid to elongate, transclucent
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...
, thin-walled, amyloid
Amyloid
Amyloids are insoluble fibrous protein aggregates sharing specific structural traits. Abnormal accumulation of amyloid in organs may lead to amyloidosis, and may play a role in various neurodegenerative diseases.-Definition:...
, and have dimensions of 8.3–11.6 by 4.9–6.6 µm. The basidia (spore-bearing cells) are 38–46 by 9–11 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...
, club-shaped, mostly 4-spored but some are 2- or 3- spored, with clamps. The cheilocystidia (cystidia found on the edge of a gill) are 23.3–31.5 by 11.6–15.7 µm, ellipsoid, club- to pear-shaped cells, partly in short rows. The cap cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
is up to 168 µm thick, and consists of thin-walled interwoven 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 are 2–5.3 µm diameter, and gelatinized. Clamp connection
Clamp connection
A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...
s are present in the hyphae of this species—these are short branches connecting one cell to the previous cell to allow passage of the products of nuclear division.
Edibility
The edibility of A. onusta is unknown, but the mushroom has been described as "possibly poisonous". In general, species of Amanita are best avoided for consumption because of the prevalence of toxicMushroom poisoning
Mushroom poisoning refers to harmful effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells...
species in that genus.
Similar species
Amanita onusta may be confused with A. cinereoconia because of the similar gray powdery veil remnants on the cap surface. A. cinereoconia is distinguished from A. onusta by the absence of clampsClamp connection
A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...
, its powdery-wooly to powdery-warty cap, as well as the absence of warts or scales at the base of the stem. A. cinereoconia also smells distinctly of chloride of lime. Another similar species is A. costaricensis, found only in Costa Rica. A. atkinsoniana, another North American species, has shorter warts that are spaced further apart than those of A. onusta, and the warts on the basal bulb are arranged in parallel rows.
Habitat and distribution
Amanita onusta grows solitary or scattered on the ground in mixed oakOak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, hickory
Hickory
Trees in the genus Carya are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts...
and chestnut
Chestnut
Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...
forests from southern 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...
to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. The species has a preference for sandy or loose soils. Its range extends north to Nova Scotia, Canada, and south to Mexico.