''Russula cyanoxantha'', commonly known as the charcoal burner or variegated russula, is a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basid ...

mushroom. It can be confused for a number of other members of its genus. Found mostly in Europe (with North American counterparts), it is an

edible mushroom Edible mushrooms are the fleshy fruit bodies of numerous species of macrofungi (fungi that bear fruiting structures large enough to be seen with the naked eye). Edibility may be defined by criteria including the absence of poisonous effect ...

Description

The most salient characteristic is the weak gills, which feel greasy to the touch, are flexible and do not break. The cap is wide, convex at first and later flattened, and greenish to bright brown; they vary considerably in color. The white-to-cream

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

are sometimes forked and are not as brittle as most other members of the genus. The stipe is pure white, slightly convex underneath, from in height and in diameter. The spores are white, as is the

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing warm orange ("tussock") color spore print. ...

. The stipe does not produce a salmon reaction when rubbed with ferrous sulphate.

Similar species

The cap of the grey-green '' Russula grisea'' is more blue-grey but has violet or green hues with light cream gills; it also grows in mixed forests, particularly under beech, and more rarely in

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

ous forests. '' Russula olivacea'' also may have a variegated cap, but produces yellow spores. '' R. aerugineais'' is greenish and has forked gills. '' R. variata'' is frequently forked and found in the east. '' R. versicolor'' has yellowish, unforked gills.

Habitat and distribution

''Russula cyanoxantha'' grows in slightly

acidic An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the ...

, but nutrient-rich soil. Like all ''Russulas'', it is a

mycorrhiza A mycorrhiza (; , 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 plant's rhizosphere, the plant root system and its surroundings. Mycorrhizae play ...

l fungus. It is found most commonly in

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

forests, and often in deciduous or mixed forests. It is possible that only European specimens are actually ''R. cyanoxantha''. It has been described as appearing from July to October in eastern North America and the

Mountain states The Mountain states (also known as the Mountain West or the Interior West) form one of the nine geographic divisions of the United States that are officially recognized by the United States Census Bureau. It is a subregion of the Western Un ...

, and from October to January further west.

Uses

The

is suitable for many kinds of preparation; the flesh is not as hard as that of many other edible Russulas. It has a mild, nutty taste, but is also appreciated by maggots.

In culture

It was designated "Mushroom of the Year" in 1997 by the German Association of Mycology.

References

*E. Garnweidner. ''Mushrooms and Toadstools of Britain and Europe''. Collins. 1994.

External links

* *
Russulales News page on ''Russula cyanoxantha''
{{Taxonbar, from=Q246696 cyanoxantha Fungi of Europe Edible fungi Taxa named by Jacob Christian Schäffer Fungi described in 1774 Fungus species