Tricholoma album
Encyclopedia
Tricholoma album, commonly known as the white knight, is an all-white 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 large genus Tricholoma. It is found in Europe, India, and possibly North America. 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...

 and gills are white. The whitish 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...

 has no ring
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...

.

Taxonomy, naming, and classification

The species was originally described as Agaricus albus by Jacob Christian Schäffer
Jacob Christian Schäffer
Jakob or Jacob Christian Gottlieb Schäffer or Schäffern was a German dean, professor, botanist, mycologist, entomologist, ornithologist and inventor.-Biography:...

 in 1774, and reclassified as Gyrophila alba by mycologist Lucien Quélet
Lucien Quélet
thumb|Lucien QuéletLucien Quélet was a French mycologist and naturalist who discovered several species and was the founder of the Société mycologique de France, a society devoted to mycological studies....

 in 1886. It was given its current binomial name by German Paul Kummer
Paul Kummer
Paul Kummer was a priest, teacher, and scientist in Zerbst, Germany, known chiefly for his contribution to mycological nomenclature. Earlier classification of agarics by pioneering fungal taxonomist Elias Magnus Fries designated only a very small number of genera, with most species falling into...

 in 1871. The British Mycological Society
British Mycological Society
The British Mycological Society is a learned society established in 1896 to promote the study of fungi.-Formation:The Society was formed based on the efforts of two local societies, the Woolhope Naturalists' Field Club of Hereford and the Yorkshire Naturalists’ Union. The curator of the Hereford...

 has listed "white knight" as its common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

. The generic name derives from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 trichos/τριχος 'hair' and loma/λωμα 'hem', 'fringe' or 'border', while the specific epithet is the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 adjective albus "white".

The fungus is classified in the section Lasciva of the genus Tricholoma, characterised by species with a strong odor and acrid or bitter taste; an older classification has it placed in section Inamoena.

Marcel Bon
Marcel Bon
Marcel Bon is one of France’s best known field mycologists. He was born in Picardy, in 1925 and came to mycology through general botany, and pharmacology...

 named the variety Tricholoma album var. thalliophilum to account for those mushrooms that differed by staining blue-green with thallium oxide
Thallium(I) hydroxide
Thallium hydroxide, also called thallous hydroxide, TlOH, is a hydroxide of thallium, with thallium in oxidation state +1. Thallous hydroxide is a strong base; it is changed to thallous ion, Tl+, except in strongly basic conditions.-References:...

 and sulfoformol; in the absence of additional differentiating characters, some later authors have questioned the taxonomical
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 value of this characteristic.

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 3–7.5 cm (1.2–3 in) wide and white with a pale yellow tinge, and more yellow or ochre in the centre as the fruit body ages. Convex with a slight boss, the cap is broadly conical in shape with inrolled margins. The white to pale yellow or ochre-tinged 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 3–8.5 cm (1.2–3.4 in) high and 0.8–1.5 cm wide and has no ring. There is no ring or volva
Volva (mycology)
The volva is a mycological term to describe a cup-like structure at the base of a mushroom that is a remnant of the universal veil. This macrofeature is important in wild mushroom identification due to it being an easily observed, taxonomically significant feature which frequently signifies a...

. The mushroom has a prominent unpleasant sweet smell reminiscent of honey and radishes, and has an acrid and disagreeable taste. The thick gills are widely spaced with finely serrated edges. 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 white, the oval or oblong 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 5–7 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...

 long by 3.5–5 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...

 wide.

Ecology, habitat and distribution

Tricholoma album is found across Europe, the fruit bodies appearing between August and December, in association with oak (Quercus) trees, with which they form a mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

l relationship. Experiments have demonstrated that inoculating blue pine (Pinus wallichiana) and deodar (Cedrus deodara) seedlings with the fungus increases plant height and shoot and root biomass. The mushroom can be encountered growing in sizeable fairy ring
Fairy ring
A fairy ring, also known as fairy circle, elf circle, elf ring or pixie ring, is a naturally occurring ring or arc of mushrooms. The rings may grow to over in diameter, and they become stable over time as the fungus grows and seeks food underground. They are found mainly in forested areas, but...

s. The presence of the mushroom in North America has not been confirmed. It has been reported from India in 2010.
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