Lactarius vietus
Encyclopedia
Lactarius vietus is a species of fungus
in the family Russulaceae
, first described
by Elias Magnus Fries
. It produces moderately sized and brittle mushroom
s, which grow on the forest floor
or on rotting wood. The flattened-convex cap
can vary in shape, sometimes forming the shape of a wide funnel. It is typically grey, but the colour varies. The species has crowded, light-coloured gills, which produce white milk
. The spore print
is typically whitish, but also varies considerably. The mushrooms typically have a strong, acrid taste and have been described as inedible, but other authors have described them as consumable after boiling. L. vietus feeds by forming an ectomycorrhizal relationship with surrounding trees, and it favours birch
. It grows in autumn months and is fairly common in Europe, North America and eastern Asia.
by Elias Magnus Fries
in 1821 as Agaricus vietus in his Systema Mycologicum
. In his 1838 work Epicrisis systematis mycologici, Fries reclassified the species as a Lactarius, giving it its current name. Subsequent attempts to reclassify the species have been unsuccessful. In his 1871 work Der Führer in die Pilzkunde, Paul Kummer
reclassified the species as a member of Galorrheus, and in Otto Kuntze
's 1891 Revisio generum plantarum, the species was placed in the genus Lactifluus. Both Galorrheus vietus and Lactifluus vietus are now considered obligate synonyms (different names for the same species based on one type) of Lactarius vietus. The specific epithet is from the Latin
vietus, meaning shrunken. It is commonly known
as the grey milkcap.
of 2.5 to 7.5 cm (0.984251968503937 to 3 in) across, with a flattened-convex shape. At times, the cap becomes widely funnel-shaped, and sometimes features a broad or pointed umbo
, though the centre of the cap is typically depressed. The cap is coloured grey, sometimes with violet, flesh-coloured, pale yellowish-brown or red tints, though it is paler towards the cap margin in young mushrooms. Very pale specimens have also been recorded in the United States, though they are not true albinos. The cap's margin is curved inwards in younger specimens, and wavey. The cap surface is smooth, and can be slimey or sticky when wet. The stem
measures 2.5 to 8 cm (0.984251968503937 to 3.1 in) by 2 to 7 cm (0.78740157480315 to 2.8 in), and is generally cylindrical in shape. Sometimes the stem narrows downwards, or is club-shaped. In colour, the stem whitish or greyish, paler at the top, and is rather weak and easily broken. The flesh
is a whitish-buff
colour, and is often absent in the stem, leaving it hollow. The crowded gills are can be decurrent
(with the gill running down the stem) or adnate
(with the entire depth of the gill connecting to the stem), and in colour are whitish to a dirty buff. They are thin and flaccid, and there are three to four tiers of lamellulae (short gills that do not reach the stem from the cap margin). The gills produce white milk
, which dries a brownish or greenish grey after about 20 minutes. The mushroom flesh will slowly stain a greyish colour if a drop of FeSO4
solution is applied to it as a chemical color test
.
is typically a creamy white, with a slight salmon tinge, but it has been observed to vary from white to yellow depending on the density, meaning that it is not a useful means of identification. Individual spores are a buff-white, amyloid
(staining blue in Melzer's reagent
) and hyaline
. In shape, the spores are elliptic, with a moderately well-developed network of ridges, measuring between 8 and 9.5 by 6.5 to 7.5 micrometre
s (μm). The pleurocystidia (cystidia on the face of the gills) are shaped like narrow spindle
s, typically measuring between 40 and 75 μm long, but sometimes reaching 86 μm in length, by 6 and 11 μm wide at the widest point. The cheilocystidia (cystidia on the edge of the gills) are leaf or spindle shaped, measuring between 30 and 52 μm long by 4 to 7 μm wide. The basidia are four-spored and club-shaped, measuring between 36 and 42 μm in length by 8 and 12 μm wide.
is similar in appearance. In colour, it is a pale pink-buff, and its flesh turns a violet-lilac colour when cut. The white milk has a mild taste. Lactarius mammosus, a species described by Fries but not often mentioned by the mycological community for some time after his death, is also similar. Meinhard Moser, examining the identity of L. mammosus, concluded that it "is certainly more closely related to L. vietus than to L. fuscus,
but differs in habit and colour. The spores are slightly longer and the sculptures are less pronounced in L. vietus."
moss. Though it strongly favours beech
, it has also been found under oak
. It forms an ectomycorrhizal relationship with the trees under which it grows. It can also be found growing on rotting wood or other hard surfaces; specimens have been observed on both conifer and hardwood
logs. These are typically smaller specimens, and it is possible that they represent a dwarf
variety. Despite growing on rotting wood, the species is not saprotrophic
; instead, the mycelia of the species are linking with tree roots growing through or near the wood. This is a particularly useful adaptation when the soil is either wet or nutrient-poor. Mushrooms can sometimes grow in large numbers, but they can also be found growing in tight clumps, or solitarily when growing out of season. The species can be found in Europe, with collections in Scandinavia, the British Isles Bulgaria, Germany, and northern Turkey; in North America, it has been recorded as common in Canada and both the northern and southern United States; in northern Asia, it was found in regions near both the Oka River
and the central Angara River
in Siberia; and in eastern Asia, it has been collected in China.
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
in the family Russulaceae
Russulaceae
The Russulaceae are a family of fungi in the order Russulales. According to a 2008 estimate, the family contains 1243 species. Its species typically have fruit bodies with friable, chalk-like stalks, that break with a distinct crack, somewhat like a carrot but with porous flesh...
, first described
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
by Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
. It produces moderately sized and brittle 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, which grow on the forest floor
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
or on rotting wood. The flattened-convex 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...
can vary in shape, sometimes forming the shape of a wide funnel. It is typically grey, but the colour varies. The species has crowded, light-coloured gills, which produce white milk
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...
. 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 typically whitish, but also varies considerably. The mushrooms typically have a strong, acrid taste and have been described as inedible, but other authors have described them as consumable after boiling. L. vietus feeds by forming an ectomycorrhizal relationship with surrounding trees, and it favours 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...
. It grows in autumn months and is fairly common in Europe, North America and eastern Asia.
Taxonomy
Lactarius vietus was first describedSpecies description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
by Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
in 1821 as Agaricus vietus in his Systema Mycologicum
Systema Mycologicum
Systema Mycologicum is a systematic classification of fungi drawn up in 1821 by the Swedish mycologist and botanist Elias Fries. It took 11 years to complete....
. In his 1838 work Epicrisis systematis mycologici, Fries reclassified the species as a Lactarius, giving it its current name. Subsequent attempts to reclassify the species have been unsuccessful. In his 1871 work Der Führer in die Pilzkunde, 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...
reclassified the species as a member of Galorrheus, and in Otto Kuntze
Otto Kuntze
Otto Carl Ernst Kuntze was a German botanist.-Biography:Otto Kuntze was born in Leipzig.An apothecary in his early career, he published an essay entitled Pocket Fauna of Leipzig. Between 1863 and...
's 1891 Revisio generum plantarum, the species was placed in the genus Lactifluus. Both Galorrheus vietus and Lactifluus vietus are now considered obligate synonyms (different names for the same species based on one type) of Lactarius vietus. The specific epithet is from 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...
vietus, meaning shrunken. It is commonly known
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...
as the grey milkcap.
Description
Lactarius vietus typically has a 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...
of 2.5 to 7.5 cm (0.984251968503937 to 3 in) across, with a flattened-convex shape. At times, the cap becomes widely funnel-shaped, and sometimes features a broad or pointed umbo
Umbo (mycology)
thumb|right|[[Cantharellula umbonata]] has an umbo.thumb|right|The cap of [[Psilocybe makarorae]] is acutely papillate.An umbo is a raised area in the center of a mushroom cap. Caps that possess this feature are called umbonate. Umbos that are sharply pointed are called acute, while those that are...
, though the centre of the cap is typically depressed. The cap is coloured grey, sometimes with violet, flesh-coloured, pale yellowish-brown or red tints, though it is paler towards the cap margin in young mushrooms. Very pale specimens have also been recorded in the United States, though they are not true albinos. The cap's margin is curved inwards in younger specimens, and wavey. The cap surface is smooth, and can be slimey or sticky when wet. 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...
measures 2.5 to 8 cm (0.984251968503937 to 3.1 in) by 2 to 7 cm (0.78740157480315 to 2.8 in), and is generally cylindrical in shape. Sometimes the stem narrows downwards, or is club-shaped. In colour, the stem whitish or greyish, paler at the top, and is rather weak and easily broken. 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 a whitish-buff
Buff (colour)
Buff is a pale yellow-brown colour that got its name from the colour of buff leather.Displayed on the right is the colour buff.EtymologyAccording to the Oxford English Dictionary, buff as a descriptor of a colour was first used in the London Gazette of 1686, describing a uniform to be "A Red Coat...
colour, and is often absent in the stem, leaving it hollow. The crowded gills are can be decurrent
Decurrent
Decurrent is a term used in botany and mycology to describe plant or fungal parts that extend downward.In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petiole and extend down along the stem...
(with the gill running down the stem) or adnate
Adnation
Adnation in plants is the "union of unlike parts; organically united or fused with another dissimilar part, e.g. an ovary to a calyx tube, or stamens to petals". This is in contrast to connation, the fusion of similar organs....
(with the entire depth of the gill connecting to the stem), and in colour are whitish to a dirty buff. They are thin and flaccid, and there are three to four tiers of lamellulae (short gills that do not reach the stem from the cap margin). The gills produce white milk
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...
, which dries a brownish or greenish grey after about 20 minutes. The mushroom flesh will slowly stain a greyish colour if a drop of FeSO4
Iron(II) sulfate
Iron sulfate or ferrous sulfate is the chemical compound with the formula FeSO4. Known since ancient times as copperas and as green vitriol, the blue-green heptahydrate is the most common form of this material...
solution is applied to it as a chemical color test
Chemical tests in mushroom identification
Chemical tests in mushroom identification are methods that aid in determining the variety of some fungi. The most useful tests are Melzer's reagent and potassium hydroxide.- Ammonia :Household ammonia can be used. A couple of drops are placed on the flesh...
.
Microscopic features
The spore printSpore 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 typically a creamy white, with a slight salmon tinge, but it has been observed to vary from white to yellow depending on the density, meaning that it is not a useful means of identification. Individual spores are a buff-white, amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
(staining blue in Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
) and hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
. In shape, the spores are elliptic, with a moderately well-developed network of ridges, measuring between 8 and 9.5 by 6.5 to 7.5 micrometre
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...
s (μm). The pleurocystidia (cystidia on the face of the gills) are shaped like narrow spindle
Spindle (textiles)
A spindle is a wooden spike used for spinning wool, flax, hemp, cotton, and other fibres into thread. It is commonly weighted at either the bottom middle or top, most commonly by a circular or spherical object called a whorl, and may also have a hook, groove or notch, though spindles without...
s, typically measuring between 40 and 75 μm long, but sometimes reaching 86 μm in length, by 6 and 11 μm wide at the widest point. The cheilocystidia (cystidia on the edge of the gills) are leaf or spindle shaped, measuring between 30 and 52 μm long by 4 to 7 μm wide. The basidia are four-spored and club-shaped, measuring between 36 and 42 μm in length by 8 and 12 μm wide.
Similar species
Lactarius uvidusLactarius uvidus
Lactarius uvidus is a European and North American "milk-cap" mushroom, of which the milk turns violet when the flesh is damaged. The fungi generally identified as L. uvidus are part of a complex of closely related species and varieties which are difficult to delimit definitively, .It gives its...
is similar in appearance. In colour, it is a pale pink-buff, and its flesh turns a violet-lilac colour when cut. The white milk has a mild taste. Lactarius mammosus, a species described by Fries but not often mentioned by the mycological community for some time after his death, is also similar. Meinhard Moser, examining the identity of L. mammosus, concluded that it "is certainly more closely related to L. vietus than to L. fuscus,
but differs in habit and colour. The spores are slightly longer and the sculptures are less pronounced in L. vietus."
Edibility
Lactarius vietus milk has a very hot taste, and the mushroom lacks a distinctive smell. Although described by many mycologists as inedible, David Pegler claims that its acrid taste can be removed after boiling, allowing it to be consumed. Though the strong, acrid taste is a defining feature of the species, it is weaker or even absent in some older mushrooms, which is not unusual for Lactarius species. Occasionally, however, mushrooms of the species have been collected which have a mild taste; this has also been observed in other species with typically acrid tastes.Distribution, habitat and ecology
Lactarius vietus is fairly common, and can be found growing in moist areas under trees in autumn, often among SphagnumSphagnum
Sphagnum is a genus of between 151 and 350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. A distinction is made between sphagnum moss, the live moss growing on top of a peat bog on one hand, and sphagnum peat moss or sphagnum peat on the other, the...
moss. Though it strongly favours beech
Beech
Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
, it has also been found under oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
. It forms an ectomycorrhizal relationship with the trees under which it grows. It can also be found growing on rotting wood or other hard surfaces; specimens have been observed on both conifer and hardwood
Hardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...
logs. These are typically smaller specimens, and it is possible that they represent a dwarf
Dwarfing
Dwarfing is a characteristic in plants and animals whereby one or more members of a breed or cultivar are significantly smaller than standard members of their species...
variety. Despite growing on rotting wood, the species is not saprotrophic
Saprotrophic nutrition
Saprotrophic nutrition is a process of chemoheterotrophic extra-cellular digestion involved in the processing of dead or decayed organic matter that occurs in saprotrophs or heterotrophs, and is most often associated with fungi, for example Mucor and Rhizopus...
; instead, the mycelia of the species are linking with tree roots growing through or near the wood. This is a particularly useful adaptation when the soil is either wet or nutrient-poor. Mushrooms can sometimes grow in large numbers, but they can also be found growing in tight clumps, or solitarily when growing out of season. The species can be found in Europe, with collections in Scandinavia, the British Isles Bulgaria, Germany, and northern Turkey; in North America, it has been recorded as common in Canada and both the northern and southern United States; in northern Asia, it was found in regions near both the Oka River
Oka River
Oka is a river in central Russia, the largest right tributary of the Volga. It flows through the regions of Oryol, Tula, Kaluga, Moscow, Ryazan, Vladimir, and Nizhny Novgorod and is navigable over a large part of its total length, as far upstream as to the town of Kaluga. Its length exceeds...
and the central Angara River
Angara River
The Angara River is a long river in Irkutsk Oblast and Krasnoyarsk Krai, south-east Siberia, Russia. It is the only river flowing out of Lake Baikal, and is the headwater tributary of the Yenisei River....
in Siberia; and in eastern Asia, it has been collected in China.
External links
- Lactarius vietus at RogersMushrooms