Agaricus albolutescens
Encyclopedia
Agaricus albolutescens is a moderate-sized, stocky statured 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...

 that has a pleasant odor and bruises slowly but persistently yellow. This character distinguishes it from other Agaricus
Agaricus
Agaricus is a large and important genus of mushrooms containing both edible and poisonous species, with possibly over 300 members worldwide...

species, such as Agaricus xanthodermus, a mildly toxic species which has a phenolic or medicinal odor, and bruises fleetingly yellow. Fieldmarks of Agaricus albolutescens include a tendency to discolor tawny-brown, rather than merely yellow, and chocolate-brown free gills. Agaricus silvicola is very similar but has a less dramatic bruising reaction, more yellowish than tawny, a normal rather than stocky stature, and slightly smaller spores. It is believed that Agaricus albolutescens and Agaricus silvicola represent a single polymorphic
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...

 species or a species complex.

Pileus
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...

The cap is 6-12 cm broad, and convex; it becomes plano-convex to plano-depressed. Meanwhile, the margin is incurved, then decurved, overlapping the gills. Occasionally, it is wavy and appendiculate from veil fragments. The surface is dry and white; when bruised, it turns tawny-brown. The context varies from 1.5 to 2.0 cm thick; it is firm and turns pale-peach when cut. When the flesh is dry, odor and taste is musty.

Lamellae

The gills are free, close, and, at first, pallid, though they then turn a pale pinkish-tan. As it ages, A. albsolutescens are dark chocolate-brown in color. The lamellulae are in five to six series.

Stipe

The stipe
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 2.0-7.0 cm long, 1.5-3.0 cm thick, and more or less equal except for a bulbous base. In addition, it has a narrow, cottony central core. The surface of the apex is palled and finely striate, while the lower stipe
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...

 can vary from glabrous to sparsely covered with whitish fibrils, occasionally sheathed with cottony-floccose veil remnants. Like the cap, it yellows. The 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 layered. The surface underneath can be cottony or fibrillose. Sometimes, it fragments, leaving scattered cottony patches over a membranous-tomentose basement layer. The annulus
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...

 is superior, thin, and initially erect, then pendulous.

Spores

Spores are 6.0-7.5 x 4.0-5.0 µm, elliptical, and inequilateral in profile. In addition, they are smooth, moderately thick-walled, and have an inconspicuous hilar
Hilum (biology)
In botany, the hilum is a scar or mark left on a seed coat by the former attachment to the ovary wall or to the funiculus...

 appendage. Their germ pore
Germ pore
A germ pore is a small pore in the outer wall of a fungal spore through which the germ tube exits upon germination. It can be apical or eccentric in its location, and, on light microscopy, may be visualized as a lighter coloured area on the cell wall....

is absent.
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