''Amanita vaginata'', commonly known as the grisette or the grisette amanita, is an

edible mushroom Edible mushrooms are the fleshy fruit bodies of numerous species of macrofungi (fungi that bear fruiting structures large enough to be seen with the naked eye). Edibility may be defined by criteria including the absence of poisonous effect ...

in the fungus family

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

. The

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. The origin of the word "cap" comes from the Old French word "chapeau" which means "head co ...

is gray or brownish, in diameter, and has furrows around the edge that duplicate the gill pattern underneath. Unlike many other ''

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 mushroom, edible species (and many species of unknown edibility). The genus is re ...

'' mushrooms, ''A. vaginata'' lacks a ring on the stem. ''A. vaginata'' is widely distributed in Europe and North America. It is not recommended for consumption due to the possibility of confusing it with related

poisonous A poison is any chemical substance that is harmful or lethal to living organisms. 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 figurati ...

species.

Description

The

is 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 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 ...

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 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, ...

is white and thin, and does not change color upon bruising. The

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

is long and thick.Google Books
/ref> Unlike many other Amanitas with stems that are swollen at the base (bulbous), the thickness of the stem is about 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 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing warm orange ("tussock") color 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

spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

are roughly spherical, 8–12

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

in diameter, thin-walled, and nonamyloid (that is, not absorbing iodine stain in

Melzer's reagent Melzer's reagent (also known as Melzer's iodine reagent, Melzer's solution or informally as Melzer's) is a chemical reagent used by mycologists to assist with the identification of fungi, and by phytopathologists for fungi that are plant pathogens ...

). The pileipellis (cap cuticle) is composed of filamentous interwoven

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e, 2–7 μm diameter, gelatinized. The spore-bearing cells, the

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

, are 36–52 by 4–13 μm, 4–sterigmate, without

clamps Clamp may refer to: Tools and devices *Brick clamp, an early method of baking bricks *Clamp (tool), a device or tool used to hold objects in a fixed relative position (many types listed) **C-clamp **C-clamp (stagecraft) **Riser clamp, a device u ...

. 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.

Similar species

The tawny grisette (''

Amanita fulva ''Amanita fulva'', commonly called the tawny grisette or the orange-brown ringless amanita, is a basidiomycete mushroom of the genus ''Amanita''. It is found frequently in deciduous and coniferous forests of Europe, and possibly North America. ...

'') was once thought to be a variety of ''A. vaginata''.Google Books
/ref> In North America, ''A. vaginata'' is considered to be part of a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

that includes ''A. constricta'', ''A. pachycolea'' and ''A. protecta''.

Distribution and habitat

This species is widely distributed in North America. It is also found in the

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

, Australia, Iran and Scotland. A

mycorrhiza A mycorrhiza (; , mycorrhiza, or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant's rhizosphere, the plant root system and its surroundings. Mycorrhizae play ...

l species, ''A. vaginata'' grows singly or numerous in both

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

ous and

hardwood Hardwood is wood from Flowering plant, angiosperm trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal ecosystem, boreal latitudes they are mostly deciduous, but in tropics and subtropics mostl ...

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.

Ecology

One field guide notes that cows enjoy eating this mushroom.

Edibility

Although not poisonous, most authors advise against consumption due to the possibility of mistaking it with poisonous species of ''Amanita''.Google Books
/ref>

References

External links

Index Fungorum
Synonyms

{{Taxonbar, from=Q913459 vaginata Fungi of North America Fungi of Australia Fungi of Europe Fungi described in 1783 Fungus species