Amanita vaginata
Encyclopedia
Amanita vaginata, commonly known as the grisette, is an edible mushroom
in the Amanitaceae
family of fungi. Unlike many other Amanita mushrooms, A. vaginata lacks a ring on the stem. The cap
is gray or brownish, 5 to 10 cm (2 to 3.9 in) in diameter, and has furrows around the edge that duplicate the gill pattern underneath. It has a widespread distribution in North America, and is thought to be part of a species complex
that includes other similar-looking Amanitas.
is 3 to 10 cm (1.2 to 3.9 in) in diameter and gray to grayish-brown in color; initially the cap is oval, then as it matures it becomes progressively conical, convex, and eventually flattened, sometimes with a small umbo (a rounded elevation in the center of the cap). The gills are white, free (not attached to the stem) to narrowly attached, moderately crowded together, and sometimes have a grayish tint; the lamellulae (small gills that run from the edge of the cap towards the stem) are truncate. The flesh
is white and thin, and does not change color upon bruising or injury. The stem
is 8 to 22 cm (3.1 to 8.7 in) long and 1 to 2 cm (0.393700787401575 to 0.78740157480315 in) thick. Unlike many other Amanitas with stems that are swollen at the base (bulbous), the thickness of the A. vaginata stem is roughly the same at both ends. The stem surface is covered with a finely powdered bloom (pruinose), especially near the top; faint longitudinal lines may be seen. The base of the stem is enclosed in a loose, sack-like volva
that may discolor grayish or reddish brown. The spore print
is white.
The variant A. vaginata var. alba is pure white, and has a volva that is either absent, or not constricted around the base of the stem.
are roughly spherical, 8–12 µm in diameter, thin-walled, and nonamyloid
(that is, not absorbing iodine stain in Melzer's reagent
). The pileipellis (cap cuticle) is composed of filamentous interwoven hypha
e, 2–7 µm diameter, gelatinized. The spore-bearing cells, the basidia, are 36–52 by 4–13 µm, 4–sterigmate, without clamps
. The volva is largely made of filamentous hyphae, 2–8 µm diameter, inflated cells broadly elliptic, elliptical, fusiform, to clavate, 40–85 by 10–35 µm, mostly terminal. The stem tissue
is made up of filamentous hyphae with diameters of 2–6 µm; the inflated cells are terminal, club-shaped, longitudinally oriented, with dimensions of up to 289 by 31 µm.
) was once thought to be a variety of A. vaginata. In North America, A. vaginata is considered to be part of a species complex
, that includes A. constricta, A. pachycolea and A. protecta.
forests. It has also been noted to occur frequently in grassy areas at the edge of forests, unkempt lawns, and suburban area where the ground has been recently disturbed. A widely distributed and common species, it fruits from the spring to the fall.
This species is widely distributed in North America. It is also found in the Azores
, Australia, and Scotland.
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...
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 fungi. Unlike many other Amanita mushrooms, A. vaginata lacks a ring on the stem. 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...
is gray or brownish, 5 to 10 cm (2 to 3.9 in) in diameter, and has furrows around the edge that duplicate the gill pattern underneath. It has a widespread distribution in North America, and is thought to be part of a species complex
Species complex
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...
that includes other similar-looking Amanitas.
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...
is 3 to 10 cm (1.2 to 3.9 in) in diameter and gray to grayish-brown in color; initially the cap is oval, then as it matures it becomes progressively conical, convex, and eventually flattened, sometimes with a small umbo (a rounded elevation in the center of the cap). The gills are white, free (not attached to the stem) to narrowly attached, moderately crowded together, and sometimes have a grayish tint; the lamellulae (small gills that run from the edge of the cap towards the stem) are truncate. 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 white and thin, and does not change color upon bruising or injury. 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 to 22 cm (3.1 to 8.7 in) long and 1 to 2 cm (0.393700787401575 to 0.78740157480315 in) thick. Unlike many other Amanitas with stems that are swollen at the base (bulbous), the thickness of the A. vaginata stem is roughly the same at both ends. The stem surface is covered with a finely powdered bloom (pruinose), especially near the top; faint longitudinal lines may be seen. The base of the stem is enclosed in a loose, sack-like 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...
that may discolor grayish or reddish brown. The spore print
Spore 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...
is white.
The variant A. vaginata var. alba is pure white, and has a volva that is either absent, or not constricted around the base of the stem.
Microscopic features
The sporesBasidiospore
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 roughly spherical, 8–12 µm in diameter, thin-walled, and nonamyloid
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:...
(that is, not absorbing iodine stain in Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
). The pileipellis (cap cuticle) is composed of filamentous 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, 2–7 µm diameter, gelatinized. The spore-bearing cells, the basidia, are 36–52 by 4–13 µm, 4–sterigmate, without clamps
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...
. The volva is largely made of filamentous hyphae, 2–8 µm diameter, inflated cells broadly elliptic, elliptical, fusiform, to clavate, 40–85 by 10–35 µm, mostly terminal. The stem tissue
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 made up of filamentous hyphae with diameters of 2–6 µm; the inflated cells are terminal, club-shaped, longitudinally oriented, with dimensions of up to 289 by 31 µm.
Similar species
The tawny grisette (Amanita fulvaAmanita fulva
Amanita fulva, commonly called the tawny grisette, is a basidiomycete mushroom of the genus Amanita. It is found frequently in deciduous and coniferous forests of Europe, and possibly North America.-Taxonomy and naming:...
) was once thought to be a variety of A. vaginata. In North America, A. vaginata is considered to be part of a species complex
Species complex
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...
, that includes A. constricta, A. pachycolea and A. protecta.
Edibility
Although not poisonous, most authors advise against consumption due to the possibility of mistaking other poisonous species of Amanita for it. One field guide notes that cows enjoy eating this mushroom.Habitat and distribution
A mycorrhizal species, Amanita vaginata grows singly or numerous in both coniferous and hardwoodHardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...
forests. It has also been noted to occur frequently in grassy areas at the edge of forests, unkempt lawns, and suburban area where the ground has been recently disturbed. A widely distributed and common species, it fruits from the spring to the fall.
This species is widely distributed in North America. It is also found in the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, Australia, and Scotland.
External links
- Index Fungorum Synonyms
- Pictures and description