Lactarius vinaceorufescens
Encyclopedia
Lactarius vinaceorufescens, commonly known as the yellow-staining milkcap or the yellow-latex milky, is a poisonous
species of fungus
in the Russulaceae
family. It produces mushroom
s with pinkish-cinnamon caps
up to 12 cm (4.7 in) wide held by pinkish-white stems
up to 7 cm (2.8 in) long. The closely spaced whitish to pinkish buff gills develop wine-red spots in age. When it is cut or injured, the mushroom oozes a white latex
that rapidly turns bright sulfur-yellow. The species, common and widely distributed in North America, grows in the ground in association with conifer trees. There are several other Lactarius species that bear resemblance to L. vinaceorufescens, but most can be distinguished by differences in staining reactions, macroscopic characteristics, or habitat.
and Alexander H. Smith
in 1960, based on specimens collected in Muskegon, Michigan
in 1936. In the same publication, they also named the variety Lactarius vinaceorufescens var. fallax to account for individuals with prominently projecting pleurocystidia measuring 9–12 µm
broad, but they reduced this to synonymy
with the main species in their 1979 monograph
of North American Lactarius
species. The fungus is classified in the subsection Croceini of the subgenus
Piperates in the genus Lactarius, along with other species with latex
that stains the fruit body
tissue yellow, or with latex that slowly become yellow upon exposure to air.
The specific epithet vinaceorufescens is derived from the Latin
word meaning "becoming wine reddish". The mushroom is commonly
known as the "yellow-latex milky" or the "yellow-staining milkcap".
of L. vinaceorufescens is initially convex, then becomes broadly convex to nearly flat, and reaches diameters of 4 – wide. The cap margin is rolled inwards at first, but later expands, becoming somewhat uplifted and uneven with age. The cap surface is smooth, pale pinkish-cinnamon with pinkish-buff at the margin when young, becoming darker pinkish-cinnamon to orangey-cinnamon when older, faintly zoned with bands or water spots of nearly the same color. The gills are attached to slightly decurrent, narrow, close together, and often forked near the stem. There are several tiers of lamellulae (short gills that do not fully extend to the stem from the cap margin). The gills are initially whitish to pinkish-buff, later spotting vinaceous to pinkish-brown or dark reddish-brown. The latex
that is exuded when the mushroom is cut or inured is initially white, but rapidly turns sulfur-yellow.
The stem
is 4 – long by 1 – thick, nearly equal in width throughout or enlarged slightly downward, and hollow. The stem surface is nearly smooth, with white to brownish stiff hairs at the base, pinkish-white overall, and darkening with age. The flesh
is moderately thick, white to pinkish, staining bright sulfur yellow. It has an acrid taste. The spore print
is white to yellowish. The mushrooms are poisonous; as a general rule, several guide books recommend to avoid the consumption of Lactarius species with latex that turns yellow.
The spore
s are roughly spherical to broadly ellipsoid, hyaline
(translucent), amyloid
, and measure 6.5–9 by 6–7 µm
. They are ornamented with warts and ridges that sometimes form a partial reticulum, with prominences up to 0.8 µm. The basisida
(spore-bearing cells) are four-spored, and measure 28–33 by 8–10 µm. The pleurocystidia (cystidia found on the gill faces) are roughly cylindrical to narrowly club-shaped when they are young, but soon broaden in the mid portion and taper to an abrupt point; they reach dimensions of 40–68 (up to 80 µm) by 9–13 µm. The cheilocystidia (cystidia on the gill edges) are roughly club-shaped or ventricose with acute apices, and measure 32–44 by 6–10 µm. Clamp connection
s are absent in the hypha
e. The cap cuticle
is a thin ixocutis composed of gelatinous hypha
e that are typically 2–4 µm wide. Projecting out from the cuticle surface are the ends of numerous connective hyphae, about 5–15 µm long.
. Another lookalike is L. colorascens, but it may be distinguished from L. vinaceorufescens by several features: a smaller fruit body; a whitish cap that becomes brownish-red with age and does not spot vinaceous or brown; bitter to faintly acrid latex; and slightly smaller spores. L. chrysorrheus
is also similar, but it has a whitish to pale yellowish-cinnamon cap with slightly darker spots and grows under hardwoods (especially oak) on well-drained, often sandy soil, and its gills do not discolor or spot vinaceous or brown.
Other superficially similar species include L. rubrilacteus
, L. rufus
, L. subviscidus, L. fragilis and L. rufulus
, but none of these species have the yellow staining reaction characteristic of L. vinaceorufescens. The edible
species Lactarius helvus
has an orange-brown to light grayish-brown cap with thin bands of dark grayish-brown, a watery latex, and whitish to tan flesh with an odor resembling maple sugar or burnt sugar. Lactarius theiogalus
, the "sulfur-milk Lactarius", has an oranger cap and white latex that slowly changes yellow upon exposure to air; it is typically found in broadleaf and mixed woods.
between August and October. The species is known to develop mycorrhizal associations with Douglas fir (Pseudotsuga menziesii). It is a fairly common and widely distributed species in North America. The mushroom has been found in boreal forests and high-elevation forests of the Southern Appalachians
, associated with the tree genera Picea, Abies, and Pinus. In California
, it has been noted to commonly co-occur with L. fragilis, L. rubrilacteus, Russula emetica
, and R. cremoricolor.
Mushroom poisoning
Mushroom poisoning refers to harmful effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells...
species of fungus
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 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...
family. It produces 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 with pinkish-cinnamon caps
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...
up to 12 cm (4.7 in) wide held by pinkish-white stems
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...
up to 7 cm (2.8 in) long. The closely spaced whitish to pinkish buff gills develop wine-red spots in age. When it is cut or injured, the mushroom oozes a white latex
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,...
that rapidly turns bright sulfur-yellow. The species, common and widely distributed in North America, grows in the ground in association with conifer trees. There are several other Lactarius species that bear resemblance to L. vinaceorufescens, but most can be distinguished by differences in staining reactions, macroscopic characteristics, or habitat.
Taxonomy and classification
The species was first described by American mycologists Lexemuel Ray HeslerLexemuel Ray Hesler
-External links:* Finding Aid for the Lexemuel Ray Hesler Collection, 1899-1982...
and Alexander H. Smith
Alexander H. Smith
Alexander Hanchett Smith was an American mycologist known for his extensive contributions to the taxonomy and phylogeny of the higher fungi, especially the agarics.-Early life:...
in 1960, based on specimens collected in Muskegon, Michigan
Muskegon, Michigan
Muskegon is a city in the U.S. state of Michigan. As of the 2010 census, the city population was 38,401. The city is the county seat of Muskegon County...
in 1936. In the same publication, they also named the variety Lactarius vinaceorufescens var. fallax to account for individuals with prominently projecting pleurocystidia measuring 9–12 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...
broad, but they reduced this to synonymy
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
with the main species in their 1979 monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
of North American 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...
species. The fungus is classified in the subsection Croceini of the subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Piperates in the genus Lactarius, along with other species with latex
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,...
that stains the fruit body
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
tissue yellow, or with latex that slowly become yellow upon exposure to air.
The specific epithet vinaceorufescens is derived 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...
word meaning "becoming wine reddish". The mushroom 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 "yellow-latex milky" or the "yellow-staining milkcap".
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...
of L. vinaceorufescens is initially convex, then becomes broadly convex to nearly flat, and reaches diameters of 4 – wide. The cap margin is rolled inwards at first, but later expands, becoming somewhat uplifted and uneven with age. The cap surface is smooth, pale pinkish-cinnamon with pinkish-buff at the margin when young, becoming darker pinkish-cinnamon to orangey-cinnamon when older, faintly zoned with bands or water spots of nearly the same color. The gills are attached to slightly decurrent, narrow, close together, and often forked near the stem. There are several tiers of lamellulae (short gills that do not fully extend to the stem from the cap margin). The gills are initially whitish to pinkish-buff, later spotting vinaceous to pinkish-brown or dark reddish-brown. The latex
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,...
that is exuded when the mushroom is cut or inured is initially white, but rapidly turns sulfur-yellow.
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 4 – long by 1 – thick, nearly equal in width throughout or enlarged slightly downward, and hollow. The stem surface is nearly smooth, with white to brownish stiff hairs at the base, pinkish-white overall, and darkening with age. 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 moderately thick, white to pinkish, staining bright sulfur yellow. It has an acrid taste. 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 to yellowish. The mushrooms are poisonous; as a general rule, several guide books recommend to avoid the consumption of Lactarius species with latex that turns yellow.
The 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 are roughly spherical to broadly ellipsoid, 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...
(translucent), 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...
, and measure 6.5–9 by 6–7 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...
. They are ornamented with warts and ridges that sometimes form a partial reticulum, with prominences up to 0.8 µm. The basisida
Basidium
thumb|right|500px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main...
(spore-bearing cells) are four-spored, and measure 28–33 by 8–10 µm. The pleurocystidia (cystidia found on the gill faces) are roughly cylindrical to narrowly club-shaped when they are young, but soon broaden in the mid portion and taper to an abrupt point; they reach dimensions of 40–68 (up to 80 µm) by 9–13 µm. The cheilocystidia (cystidia on the gill edges) are roughly club-shaped or ventricose with acute apices, and measure 32–44 by 6–10 µm. Clamp connection
Clamp connection
A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...
s are absent in the hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e. The cap cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
is a thin ixocutis composed of gelatinous hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e that are typically 2–4 µm wide. Projecting out from the cuticle surface are the ends of numerous connective hyphae, about 5–15 µm long.
Similar species
Lactarius xanthogalactus has nearly identical microscopic features to L. vinaceorufescens, but macroscopically, it does not have the reddish-vinaceous stains that develop on the cap, gills, and stem of L. vinaceorufescens, and it grows on the ground under oakOak
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...
. Another lookalike is L. colorascens, but it may be distinguished from L. vinaceorufescens by several features: a smaller fruit body; a whitish cap that becomes brownish-red with age and does not spot vinaceous or brown; bitter to faintly acrid latex; and slightly smaller spores. L. chrysorrheus
Lactarius chrysorrheus
Lactarius chrysorrheus is a member of the Lactarius genus, whose many members are commonly known as Milkcaps. It has recently been given the English name of the Yellowdrop Milkcap...
is also similar, but it has a whitish to pale yellowish-cinnamon cap with slightly darker spots and grows under hardwoods (especially oak) on well-drained, often sandy soil, and its gills do not discolor or spot vinaceous or brown.
Other superficially similar species include L. rubrilacteus
Lactarius rubrilacteus
Lactarius rubrilacteus is a species of mushroom of the genus Lactarius. It is also known as the bleeding milkcap, as is at least one other member of the genus, Lactarius deliciosus.-Description:...
, L. rufus
Lactarius rufus
Lactarius rufus is a common, medium sized member of the Lactarius genus, whose many members are commonly known as milkcaps. Known by the common name of the Rufous Milkcap, or the Red Hot Milk Cap in North America...
, L. subviscidus, L. fragilis and L. rufulus
Lactarius rufulus
Lactarius rufulus, commonly known as the rufous candy cap, is a species of fungus in the Russulaceae family. The fruit bodies have fleshy brownish-red caps up to wide, and closely spaced pinkish-yellow gills. The stem is up to long and thick and colored similarly to the cap...
, but none of these species have the yellow staining reaction characteristic of L. vinaceorufescens. The edible
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
species Lactarius helvus
Lactarius helvus
Lactarius helvus, commonly known as fenugreek milkcap, is a member of the large milkcap genus Lactarius in the order Russulales. Fruiting bodies can be found in Sphagnum moss in coniferous and deciduous woodland in Europe. Mushrooms are pale brown-grey or beige in colour and funnel-shaped, with...
has an orange-brown to light grayish-brown cap with thin bands of dark grayish-brown, a watery latex, and whitish to tan flesh with an odor resembling maple sugar or burnt sugar. Lactarius theiogalus
Lactarius theiogalus
Lactarius tabidus , commonly known as the Birch Milkcap, is an inedible mushroom of the genus Lactarius. It can be found in North America and Europe, and grows at the base of pine in Autumn...
, the "sulfur-milk Lactarius", has an oranger cap and white latex that slowly changes yellow upon exposure to air; it is typically found in broadleaf and mixed woods.
Habitat and distribution
The fruit bodies of Lactarius vinaceorufescens grow scattered or in groups on the ground under pinePine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
between August and October. The species is known to develop mycorrhizal associations with Douglas fir (Pseudotsuga menziesii). It is a fairly common and widely distributed species in North America. The mushroom has been found in boreal forests and high-elevation forests of the Southern Appalachians
Southern Appalachian spruce-fir forest
The Southern Appalachian spruce-fir forest is a type of montane coniferous forest that grows in the highest elevations in the southern Appalachian Mountains of the eastern United States...
, associated with the tree genera Picea, Abies, and Pinus. In California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, it has been noted to commonly co-occur with L. fragilis, L. rubrilacteus, Russula emetica
Russula 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...
, and R. cremoricolor.
External links
- YouTube Video of yellowing reaction