Mycena galopus
Encyclopedia
Mycena galopus, commonly known as the milking bonnet or the milk-drop Mycena, is an inedible species of fungus
in the Mycenaceae
family of the Agaricales
order. It produces small mushroom
s that have grayish-brown, bell-shaped, radially-grooved caps
up to 2.5 cm (0.984251968503937 in) wide. The gills are whitish to gray, widely spaced, and squarely attached
to the stem
. The slender stems are up to 8 cm (3.1 in) long, and pale gray at the top, becoming almost black at the hairy base. The stem will ooze a whitish latex
if it is injured or broken. The variety nigra has a dark gray cap, while the variety candida is white. All varieties of the mushroom occur during summer and autumn on leaf litter
in coniferous and deciduous woodland.
Mycena galopus is found in North America and Europe. The saprobic fungus is an important leaf litter decomposer, and able to utilize all the major constituents of plant litter. It is especially adept at attacking cellulose
and lignin
, the latter of which is the second most abundant renewable
organic compound in the biosphere
. The mushroom latex contains chemicals called benzoxepines, which are thought to play a role in a wound-activated chemical defense mechanism against yeasts and parasitic
fungi.
in 1800, and later transferred to the genus Mycena
by Paul Kummer
in 1871. An Australian taxon formerly considered a variety, Mycena galopus var. mellea, was raised to species level and renamed M. thunderboltensis in 1998. The variety candida was described by Jakob Emanuel Lange
in 1914 based on specimens he found in Denmark; variety nigra was named by Carleton Rea
in 1922. Mycena galopoda is an orthographical variant spelling.
The specific epithet galopus is derived from the Greek γαλα "milk", and πονς "foot". The mushroom is commonly
known as the "milking bonnet", or the "milk-drop Mycena". The varieties candida and nigra are the white and black milking bonnets, respectively.
of M. galopus is egg-shaped when young, later becoming conic to somewhat bell-shaped, and eventually reaching a diameter of 0.5 to 2.5 cm (0.196850393700787 to 0.984251968503937 ). In age it often has a margin curved inward, and a prominent umbo
. The cap surface has a hoary sheen (remnants of the universal veil
that once covered the immature fruit body) that soon sloughs off, leaving it naked and smooth. The cap margin, which is initially pressed against the stem, is translucent when moist, so that the outline of the gills underneath the cap may be seen, and has deep narrow grooves when dry. The color is largely fuscous-black except for the whitish margin that fades to pale gray; the umbo remains blackish or becomes dark gray, sometimes with a very pale ashy gray over all when moist, and opaque and ashy gray after drying. The flesh
is thin, soft, and fragile, without any distinctive odor and taste.
The gills are subdistantly spaced, narrow, ascending-adnate, whitish to gray, usually darker in age, with edges that are pallid or grayish. The stem
is 4 to 8 cm (1.6 to 3.1 in) (rarely up to 12 cm) long, 1–2 mm thick, equal in length throughout, smooth, and fragile. The lower portion of the stem is dark blackish-brown to a dark ashy color. The apex of the stem is pallid, and the whitish base covered with coarse, stiff hairs. When broken it exudes a white milk-like liquid. The variety candida is similar in appearance to the main variety, except its fruit body is completely white. Variety nigra has a dark or blackish-gray cap, and gills that are initially whitish before turning gray.
Although not poisonous, M. galopus and the varieties candida and nigra are inedible.
, smooth, ellipsoid, occasionally somewhat pear-shaped, and very weakly amyloid
. The basidia are four-spored. The pleurocystidia and cheilocystidia are similar and very abundant, and measure 70–90 by 9–15 μm. They are narrowly fusoid-ventricose and usually have abruptly pointed tips, sometimes forked or branched near the apex, hyaline
, and smooth. The flesh of the gill is homogenous, and stains dark vinaceous-brown in iodine. The flesh of the cap has a thin but clearly differentiated pellicle, a well-developed hypoderm (the tissue layer immediately underneath the pellicle), and the remainder is filamentous. All but the pellicle stain vinaceous-brown in iodine.
as a decomposer of leaf litter
. It has been estimated in the UK to account for a large portion of the decomposition of the autumn leaf litter in British woodlands. It is able to break down the lignin
and cellulose
components of leaf litter. Grown in axenic
culture in the laboratory, the fungus mycelium has been shown to degrade (in addition to lignin and cellulose) hemicellulose
s, protein, soluble carbohydrates, and purified xylan
and pectin
using enzymes such as polyphenol oxidase
s, cellulase
s, and catalase
. It is particularly adept at breaking down lignin, which is the second most abundant renewable
organic compound in the biosphere
, after cellulose. Research also suggests that the fungus weathers soil minerals, making them more available to mycorrhizal plants. Phosphorus
, an important macronutrient influencing plant growth, typically occurs in primary minerals like apatite
, or other organic complexes, and its low solubility
often results in low phosphorus availability in soil. The biological activity of M. galopus mycelium can increase the availability of phosphorus and other nutrients, both as a result of soil acidification due to cation uptake and via the release of weathering agents such low molecular mass organic acid
s. Studies have shown that the fungus is sensitive to low concentrations of sulphite (SO32-), a byproduct of sulphur dioxide pollution, suggesting that this pollution can be toxic to the growth of the fungus (and the subsequent decomposition of leaf litter) at environmentally relevant concentrations.
The fruit bodies of Mycena galopus grow in groups to scattered on humus under hardwood
s or conifers. In the United States, it is very abundant along the Pacific Coast
from Washington to California
, and also in Tennessee
and North Carolina
; its northern distribution extends to Canada (Nova Scotia
). In Europe, it has been collected from Britain, Germany, and Norway.
, a potent antifungal metabolite
first isolated from submerged cultures of Pterula
species in 1997. The antifungal activity of pterulone is based on selective inhibition of the NADH dehydrogenase
enzyme of the electron transport chain
. A 2008 publication reported that fatty acid ester
s of benzoxepine serve as precursors to wound-activated chemical defense. When the fruit body is injured and the latex is exposed, an esterase
enzyme (an enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis
) presumably cleaves the inactive esterified benzoxepines into their active forms, where they can help defend the mushroom against yeasts and parasitic fungi. In nature, the mushroom is rarely attacked by parasitic fungi, however, it is prone to infection by the "bonnet mold" Spinellus fusiger
, which is insensitive to the benzoxepines of M. galopus. In an English field study, where the two fungi M. galopus and Marasmius androsaceus made up over 99% of the fruit bodies in a site under Sitka spruce
, the fungivorous collembolan arthropod Onychiurus latus preferred to graze on the mycelium of M. androsaceus. This selective grazing influences the vertical distribution of the two fungi in the field.
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 Mycenaceae
Mycenaceae
The Mycenaceae are a family of fungi in the order Agaricales. According to the Dictionary of the Fungi , the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholomataceae as a result of phylogenetic analyses...
family of the Agaricales
Agaricales
The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...
order. It produces small 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 that have grayish-brown, bell-shaped, radially-grooved 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 2.5 cm (0.984251968503937 in) wide. The gills are whitish to gray, widely spaced, and squarely attached
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....
to 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...
. The slender stems are up to 8 cm (3.1 in) long, and pale gray at the top, becoming almost black at the hairy base. The stem will ooze a whitish 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,...
if it is injured or broken. The variety nigra has a dark gray cap, while the variety candida is white. All varieties of the mushroom occur during summer and autumn on leaf litter
Plant litter
Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to...
in coniferous and deciduous woodland.
Mycena galopus is found in North America and Europe. The saprobic fungus is an important leaf litter decomposer, and able to utilize all the major constituents of plant litter. It is especially adept at attacking cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
and lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...
, the latter of which is the second most abundant renewable
Renewable resource
A renewable resource is a natural resource with the ability of being replaced through biological or other natural processes and replenished with the passage of time...
organic compound in the biosphere
Biosphere
The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth, a closed and self-regulating system...
. The mushroom latex contains chemicals called benzoxepines, which are thought to play a role in a wound-activated chemical defense mechanism against yeasts and parasitic
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
fungi.
Taxonomy
The mushroom was first described as Agaricus galopus by Christian Hendrik PersoonChristian Hendrik Persoon
Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...
in 1800, and later transferred to the genus Mycena
Mycena
Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...
by 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. An Australian taxon formerly considered a variety, Mycena galopus var. mellea, was raised to species level and renamed M. thunderboltensis in 1998. The variety candida was described by Jakob Emanuel Lange
Jakob Emanuel Lange
Jakob Emanuel Lange , was a Danish mycologist who studied the systematics of gilled mushrooms.His most well-known work is Flora Agaricina Danica, a five-volume plate work on the Agaricales of Denmark....
in 1914 based on specimens he found in Denmark; variety nigra was named by Carleton Rea
Carleton Rea
Carleton Rea was an English mycologist, botanist, and naturalist.-Background and education:Carleton Rea was born in Worcester, the son of the City Coroner. He was educated at The King's School and Magdalen College, Oxford, where he studied law...
in 1922. Mycena galopoda is an orthographical variant spelling.
The specific epithet galopus is derived from the Greek γαλα "milk", and πονς "foot". 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 "milking bonnet", or the "milk-drop Mycena". The varieties candida and nigra are the white and black milking bonnets, respectively.
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 M. galopus is egg-shaped when young, later becoming conic to somewhat bell-shaped, and eventually reaching a diameter of 0.5 to 2.5 cm (0.196850393700787 to 0.984251968503937 ). In age it often has a margin curved inward, and a prominent 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...
. The cap surface has a hoary sheen (remnants of the universal veil
Universal veil
In mycology, a universal veil is a temporary membranous tissue that fully envelops immature fruiting bodies of certain gilled mushrooms. The developing Caesar's mushroom , for example, which may resemble a small white sphere at this point, is protected by this structure...
that once covered the immature fruit body) that soon sloughs off, leaving it naked and smooth. The cap margin, which is initially pressed against the stem, is translucent when moist, so that the outline of the gills underneath the cap may be seen, and has deep narrow grooves when dry. The color is largely fuscous-black except for the whitish margin that fades to pale gray; the umbo remains blackish or becomes dark gray, sometimes with a very pale ashy gray over all when moist, and opaque and ashy gray after drying. 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 thin, soft, and fragile, without any distinctive odor and taste.
The gills are subdistantly spaced, narrow, ascending-adnate, whitish to gray, usually darker in age, with edges that are pallid or grayish. 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 to 8 cm (1.6 to 3.1 in) (rarely up to 12 cm) long, 1–2 mm thick, equal in length throughout, smooth, and fragile. The lower portion of the stem is dark blackish-brown to a dark ashy color. The apex of the stem is pallid, and the whitish base covered with coarse, stiff hairs. When broken it exudes a white milk-like liquid. The variety candida is similar in appearance to the main variety, except its fruit body is completely white. Variety nigra has a dark or blackish-gray cap, and gills that are initially whitish before turning gray.
Although not poisonous, M. galopus and the varieties candida and nigra are inedible.
Microscopic characteristics
The spores are 9–13 by 5–6.5 μmMicrometre
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...
, smooth, ellipsoid, occasionally somewhat pear-shaped, and very weakly 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...
. The basidia are four-spored. The pleurocystidia and cheilocystidia are similar and very abundant, and measure 70–90 by 9–15 μm. They are narrowly fusoid-ventricose and usually have abruptly pointed tips, sometimes forked or branched near the apex, 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...
, and smooth. The flesh of the gill is homogenous, and stains dark vinaceous-brown in iodine. The flesh of the cap has a thin but clearly differentiated pellicle, a well-developed hypoderm (the tissue layer immediately underneath the pellicle), and the remainder is filamentous. All but the pellicle stain vinaceous-brown in iodine.
Similar species
The "red edge bonnet", Mycena rubromarginata, is also grayish-brown, but it has gill edges that are red, and it does not ooze latex when broken. It has amyloid, pip-shaped to roughly spherical spores that measure 9.2–13.4 by 6.5–9.4 µm.Ecology, habitat, and distribution
Mycena galopus is a saprobic fungus, and plays an important role in forest ecosystemsForest ecology
Forest ecology is the scientific study of the interrelated patterns, processes, flora, fauna and ecosystems in forests. The management of forests is known as forestry, silviculture, and forest management...
as a decomposer of leaf litter
Plant litter
Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to...
. It has been estimated in the UK to account for a large portion of the decomposition of the autumn leaf litter in British woodlands. It is able to break down the lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...
and cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
components of leaf litter. Grown in axenic
Axenic
In biology, axenic describes a culture of an organism that is entirely free of all other "contaminating" organisms. The earliest axenic cultures were of bacteria or unicellular eukaryotes, but axenic cultures of many multicellular organisms are also possible...
culture in the laboratory, the fungus mycelium has been shown to degrade (in addition to lignin and cellulose) hemicellulose
Hemicellulose
A hemicellulose is any of several heteropolymers , such as arabinoxylans, present along with cellulose in almost all plant cell walls. While cellulose is crystalline, strong, and resistant to hydrolysis, hemicellulose has a random, amorphous structure with little strength...
s, protein, soluble carbohydrates, and purified xylan
Xylan
Xylan is a generic term used to describe a wide variety of highly complex polysaccharides that are found in plant cell walls and some algae. Xylans are polysaccharides made from units of xylose ....
and pectin
Pectin
Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. It was first isolated and described in 1825 by Henri Braconnot...
using enzymes such as polyphenol oxidase
Polyphenol oxidase
Polyphenol oxidase is a tetramer which contains four atoms of copper per molecule, and binding sites for two aromatic compounds and oxygen...
s, cellulase
Cellulase
400px|thumb|right|alt = Colored dice with checkered background|Ribbon representation of the Streptomyces lividans beta-1,4-endoglucanase catalytic domain - an example from the family 12 glycoside hydrolases...
s, and catalase
Catalase
Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it catalyzes the decomposition of hydrogen peroxide to water and oxygen...
. It is particularly adept at breaking down lignin, which is the second most abundant renewable
Renewable resource
A renewable resource is a natural resource with the ability of being replaced through biological or other natural processes and replenished with the passage of time...
organic compound in the biosphere
Biosphere
The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth, a closed and self-regulating system...
, after cellulose. Research also suggests that the fungus weathers soil minerals, making them more available to mycorrhizal plants. Phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
, an important macronutrient influencing plant growth, typically occurs in primary minerals like apatite
Apatite
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH−, F−, Cl− or Br− ions, respectively, in the crystal...
, or other organic complexes, and its low solubility
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
often results in low phosphorus availability in soil. The biological activity of M. galopus mycelium can increase the availability of phosphorus and other nutrients, both as a result of soil acidification due to cation uptake and via the release of weathering agents such low molecular mass organic acid
Organic acid
An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are relatively stronger acids. The relative stability of the conjugate...
s. Studies have shown that the fungus is sensitive to low concentrations of sulphite (SO32-), a byproduct of sulphur dioxide pollution, suggesting that this pollution can be toxic to the growth of the fungus (and the subsequent decomposition of leaf litter) at environmentally relevant concentrations.
The fruit bodies of Mycena galopus grow in groups to scattered on humus under 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...
s or conifers. In the United States, it is very abundant along the Pacific Coast
Pacific Coast
A country's Pacific coast is the part of its coast bordering the Pacific Ocean.-The Americas:Countries on the western side of the Americas have a Pacific coast as their western border.* Geography of Canada* Geography of Chile* Geography of Colombia...
from Washington to 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...
, and also in Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
and North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
; its northern distribution extends to Canada (Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
). In Europe, it has been collected from Britain, Germany, and Norway.
Chemistry
In 1999, Wijnberg and colleagues reported the presence of several structurally related antifungal compounds called benzoxepines in the latex of Mycena galopus. One of these compounds, 6-hydroxypterulone, is a derivative of pterulonePterulone
Pterulone is a fungal metabolite. It was initially isolated from the mycelium and liquid cultures of wood-decay fungus in the genus Pterula. The compound inhibits eukaryotic respiration by targeting the mitochondrial NADH:ubiquinone oxidoreductase....
, a potent antifungal metabolite
Metabolite
Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. Alcohol is an example of a primary metabolite produced in large-scale by industrial...
first isolated from submerged cultures of Pterula
Pterula
Pterula is a genus of fungi in the Pterulaceae family. The genus has a widespread distribution, especially in tropical regions, and contains about 50 species....
species in 1997. The antifungal activity of pterulone is based on selective inhibition of the NADH dehydrogenase
NADH dehydrogenase
NADH dehydrogenase is an enzyme located in the inner mitochondrial membrane that catalyzes the transfer of electrons from NADH to coenzyme Q...
enzyme of the electron transport chain
Electron transport chain
An electron transport chain couples electron transfer between an electron donor and an electron acceptor with the transfer of H+ ions across a membrane. The resulting electrochemical proton gradient is used to generate chemical energy in the form of adenosine triphosphate...
. A 2008 publication reported that fatty acid ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
s of benzoxepine serve as precursors to wound-activated chemical defense. When the fruit body is injured and the latex is exposed, an esterase
Esterase
An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis.A wide range of different esterases exist that differ in their substrate specificity, their protein structure, and their biological function.- EC classification/list...
enzyme (an enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
) presumably cleaves the inactive esterified benzoxepines into their active forms, where they can help defend the mushroom against yeasts and parasitic fungi. In nature, the mushroom is rarely attacked by parasitic fungi, however, it is prone to infection by the "bonnet mold" Spinellus fusiger
Spinellus fusiger
Spinellus fusiger, commonly known as the bonnet mould, is a species of fungus in the Zygomycota phylum. It is a pin mold that is characterized by erect sporangiophores that are simple in structure, brown or yellowish-brown in color, and with branched aerial filaments that bear the zygospores...
, which is insensitive to the benzoxepines of M. galopus. In an English field study, where the two fungi M. galopus and Marasmius androsaceus made up over 99% of the fruit bodies in a site under Sitka spruce
Sitka Spruce
Picea sitchensis, the Sitka Spruce, is a large coniferous evergreen tree growing to 50–70 m tall, exceptionally to 95 m tall, and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter...
, the fungivorous collembolan arthropod Onychiurus latus preferred to graze on the mycelium of M. androsaceus. This selective grazing influences the vertical distribution of the two fungi in the field.