Agaricus arorae
Encyclopedia
Agaricus arorae is a moderate-sized, forest-dwelling mushroom
that exhibits distinctive color changes. It fruits early in the mushroom season. Unique within the Agaricus genus, the mushroom's cap cuticle turns yellow when exposed to a base such as potassium hydroxide
or sodium hydroxide. In the field, it has a brownish, fibrillose/squamulose cap, which tuns red when bruised. Agaricus arorae was first described from Santa Cruz Co. but since has been found in San Mateo and Alameda counties. Agaricus arorae can be distinguished by its scales and a conspicuous stipe
.
A. arorae was named after American mycologist and author David Arora
.
dish colour, and yellows with KOH. With a dry surface, the cap's disc can be glabrous or tomentose. Toward the margin, either minute fiber
s or scales develop. The cap's fibrils are generally a brownish colour. The cap
has an indistinct odor
with a mild taste. The context can be as large as 5 mm thick, soft, and bruises irregularly a vinaceous where cut.
is 4-9 cm long and 0.5-2.5 cm thick. At the base, it is slightly enlarged and becomes stuffed at maturity. The white veil is rather membranous and yields a thin ring. When cut, the cortex discolours to pinkish-orange. The stipe base changes brown to rusty-brown from handling. The margin is sometimes light brown. The apex surface is white, and patchy fibrillose over a dull-buff ground color.
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 exhibits distinctive color changes. It fruits early in the mushroom season. Unique within the Agaricus genus, the mushroom's cap cuticle turns yellow when exposed to a base such as potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
or sodium hydroxide. In the field, it has a brownish, fibrillose/squamulose cap, which tuns red when bruised. Agaricus arorae was first described from Santa Cruz Co. but since has been found in San Mateo and Alameda counties. Agaricus arorae can be distinguished by its scales and a conspicuous 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...
.
A. arorae was named after American mycologist and author David Arora
David Arora
David Arora is an American mycologist, naturalist, and writer. He is the author of two popular books on mushroom identification, Mushrooms Demystified and All That the Rain Promises and More.......
.
Pileus
The cap is 3-8 cm broad, and varies from hemispheric to convex. The margin starts curved, but then decurved. The cuticle slowly bruises a redRed
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
dish colour, and yellows with KOH. With a dry surface, the cap's disc can be glabrous or tomentose. Toward the margin, either minute fiber
Fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
s or scales develop. The cap's fibrils are generally a brownish colour. 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...
has an indistinct odor
Odor
An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...
with a mild taste. The context can be as large as 5 mm thick, soft, and bruises irregularly a vinaceous where cut.
Lamelae
The gills are free, close, and broad. At first, they are buff-brown, but turn a darker brown in age.Stipe
The stipeStipe (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 4-9 cm long and 0.5-2.5 cm thick. At the base, it is slightly enlarged and becomes stuffed at maturity. The white veil is rather membranous and yields a thin ring. When cut, the cortex discolours to pinkish-orange. The stipe base changes brown to rusty-brown from handling. The margin is sometimes light brown. The apex surface is white, and patchy fibrillose over a dull-buff ground color.