Agaricus benesii is a agaric

Agaric

An agaric is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe , with lamellae on the underside of the pileus. "Agaric" can also refer to a basidiomycete species characterized by an agaric-type fruiting body...

 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...

 of the genus Agaricus

Agaricus

Agaricus is a large and important genus of mushrooms containing both edible and poisonous species, with possibly over 300 members worldwide...

. This mushroom can be distinguished by a white cap that bruises pinkish-red when injured, a scaly lower stipe, and a conifer habitat. Similar to Agaricus californicus

Agaricus californicus

Agaricus californicus, commonly known as the California Agaricus, is a poisonous mushroom in the section Xanthodermati of the genus Agaricus. It is mildly poisonous, causing gastrointestinal upset in many individuals...

and A. xanthodermus

Agaricus xanthodermus

Agaricus xanthodermus, commonly known as the yellow-staining mushroom, is a mushroom of thegenus Agaricus, which displays a strong yellow colouration at the base of the stem when cut...

, the cap discolors brown in age. A distinguishing feature of A. californicus and A. xanthodermus

Agaricus xanthodermus

Agaricus xanthodermus, commonly known as the yellow-staining mushroom, is a mushroom of thegenus Agaricus, which displays a strong yellow colouration at the base of the stem when cut...

, however, is a thickened 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...

 at the margin, a phenolic

Phenol

Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

 odor, and a yellowing bruise

Bruise

A bruise, also called a contusion, is a type of relatively minor hematoma of tissue in which capillaries and sometimes venules are damaged by trauma, allowing blood to seep into the surrounding interstitial tissues. Bruises can involve capillaries at the level of skin, subcutaneous tissue, muscle,...

, instead of red. In the case of Agaricus xanthodermus, it occurs quickly, though faintly to not at all in the case of A. californicus. Another similar species, Agaricus bernardii

Agaricus bernardii

Agaricus bernardii,commonly called Salt-Loving Agaricus is a mushroom in the Agaricaceae family of fungi. It partially resembles Agaricus bitorquis but it differs from that fungus by the reddish-brown staining of cap and stipe tissue as well as its briny odour...

, also stains red and has white flesh, but differentiates on its larger bulk, a sheathing veil, briny odor, and different habitat, namely grass

Grass

Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

.

Description

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 4 – broad; it has a convex shape which, in age, becomes flat. 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, moderately thick, and firm. The odor is pungent, even though the mushroom has a mild taste. When injured, it turns a pinkish-red. The surface is white, dry, and innately fibrillose. At the margin, it is finely scaled, though it discolors into a brown

Brown

Brown is a color term, denoting a range of composite colors produced by a mixture of orange, red, rose, or yellow with black or gray. The term is from Old English brún, in origin for any dusky or dark shade of color....

ish shade in age.

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 – tall and 1 – thick. The stem extends to the enlarged base. At maturity, the stem is stuffed. The surface is white, and turns smooth at the apex, while it is finely scaled below. 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 white, membranous, and two layered. The upper surface is striate, while the lower surface is composed of scaly patches, forming a small, superior annulus. The flesh is white, though it stains red quickly when injured.

The gills are initially unattached to the stem, packed close together, and are pinkish-brown; in age they become blackish-brown.
Spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s are 5–6 by 3–4 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...

, smooth, and elliptical. 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 a blackish-brown color.

Habitat

Found under Monterey Cypress and pines, Agaricus benesii are often in small groups or by themselves. In addition, they fruit from mid to late winter

Winter

Winter is the coldest season of the year in temperate climates, between autumn and spring. At the winter solstice, the days are shortest and the nights are longest, with days lengthening as the season progresses after the solstice.-Meteorology:...

.