Russula betularum
Encyclopedia
Russula betularum is a small, very pale member of the Russula
(brittlegills) genus
of mushroom
s. It is usually white to very pale pink, inedible, and grows with birch
trees. It is commonly
known as the birch brittlegill.
).
is convex to flattened, and often has a central depression. On expansion the margin becomes furrowed, and bears low warts. It is 2–5 cm (0.8–2 in) in diameter, and the cuticle may be peeled off completely. The cap ranges in colour from white to pale pink, to deep pink, and can even be pale buff. Although more often it is white with a pale pink blush, turning pale yellow ochre in the centre. The stem
is typically longer than the diameter of the cap, and is cylindrical or slightly club-shaped. It is white, and very fragile. The gills are also white, and well spaced, and the spore print
is white. The flesh
is white and tastes hot. It might be confused with Russula fragilis
(Pers.
) Fr.
which can be pale in colour, and occur in the same habitat. However, the cuticle of the latter species is only three quarters peeling, usually darker at the centre, and with purplish tones. It also has marked serrations on the gill edges.
trees. It often grows in damp places in woodlands.
ky abdominal cramps. The active agent has not been identified but thought to be sesquiterpene
s, which have been isolated from the related genus Lactarius
and from Russula sardonia
.
Russula
Around 750 worldwide species of mycorrhizal mushrooms compose the genus Russula. They are typically common, fairly large, and brightly colored - making them one of the most recognizable genera among mycologists and mushroom collectors...
(brittlegills) genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of 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...
s. It is usually white to very pale pink, inedible, and grows with birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
trees. It is commonly
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...
known as the birch brittlegill.
Taxonomy
The specific epithet betularum "of the birches", refers to its association with birch (Betula species). Some sources regard it as a variety of the sickener (R. emeticaRussula emetica
Russula emetica, commonly known as the sickener, is a basidiomycete mushroom of the genus Russula, one of many species with a predominantly red-coloured cap and white gills and stalk. It gets its common name from its inedibility, as it causes vomiting and diarrhea when consumed...
).
Description
The capPileus (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 convex to flattened, and often has a central depression. On expansion the margin becomes furrowed, and bears low warts. It is 2–5 cm (0.8–2 in) in diameter, and the cuticle may be peeled off completely. The cap ranges in colour from white to pale pink, to deep pink, and can even be pale buff. Although more often it is white with a pale pink blush, turning pale yellow ochre in the centre. 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 typically longer than the diameter of the cap, and is cylindrical or slightly club-shaped. It is white, and very fragile. The gills are also white, and well spaced, and 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 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 and tastes hot. It might be confused with Russula fragilis
Russula fragilis
The inedible wild mushroom Russula fragilis, which goes by the common name of the fragile brittlegill, is a member of the Russula genus, whose members are commonly known as brittlegills...
(Pers.
Christian Hendrik Persoon
Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...
) Fr.
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
which can be pale in colour, and occur in the same habitat. However, the cuticle of the latter species is only three quarters peeling, usually darker at the centre, and with purplish tones. It also has marked serrations on the gill edges.
Distribution and habitat
Russula betularum appears in summer and early autumn. It is widespread in Britain, Europe, and Scandinavia, and is probably mycorrhizal with birchBirch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
trees. It often grows in damp places in woodlands.
Edibility
This mushroom is inedible, and has a hot 'peppery' taste. Many bitter tasting red-capped species can cause problems if eaten raw; the symptoms are mainly gastrointestinal in nature: diarrhoea, vomiting and colicColic
Colic is a form of pain which starts and stops abruptly. Types include:*Baby colic, a condition, usually in infants, characterized by incessant crying*Renal colic, a pain in the flank, characteristic of kidney stones...
ky abdominal cramps. The active agent has not been identified but thought to be sesquiterpene
Sesquiterpene
Sesquiterpenes are a class of terpenes that consist of three isoprene units and have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be acyclic or contain rings, including many unique combinations...
s, which have been isolated from the related genus Lactarius
Lactarius
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...
and from Russula sardonia
Russula sardonia
Russula sardonia, commonly known as the primrose brittlegill, is a mushroom of the Russula genus, which are commonly known as brittlegills. The fruiting body, or mushroom, is a reddish-purple, the colour of blackberry juice, and is found in coniferous woodland in summer and autumn...
.