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

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 t ...

in the fungus 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 co ...

. Unlike many other ''Amanita'' mushrooms, ''A. vaginata'' lacks a ring on the stem. The cap is gray or brownish, 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.

Description

The cap 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). Internet Archive
/ref> 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 Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

is long and 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.

Microscopic features

The spores are roughly spherical, 8–12 μm in diameter, thin-walled, and

nonamyloid In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black stai ...

(that is, not absorbing iodine stain in Melzer's reagent). 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 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 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, 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.Google Books
/ref>Google Books
/ref> One source notes that the species is usually regarded as edible but may cause intoxication. One field guide notes that cows enjoy eating this mushroom.

Habitat and distribution

mycorrhizal A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, 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 plan ...

species, ''Amanita vaginata'' grows singly or numerous in both

coniferous Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...

and

hardwood Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...

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 ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

, Australia, Iran and Scotland.

References

External links

Index Fungorum
Synonyms

{{Taxonbar, from=Q913459 vaginata Edible fungi Fungi of North America Fungi of Australia Fungi of Europe