Leucopaxillus giganteus
Encyclopedia
Leucopaxillus giganteus, commonly
known as the giant leucopax (formerly as the giant clitocybe) or the giant funnel, is a saprobic species of fungus
in the Tricholomataceae
family. As its common names imply, the fruit body
, or mushroom, can become quite large—the cap
reaches diameters of up to 40 cm (15.7 in). It has a white or pale cream cap, and is funnel-shaped when mature, with the gills running down the length of the stem
. Considered by some to be a choice edible
when young, this species has a cosmopolitan distribution
, and is typically found growing in groups or rings
in grassy pastures, roadside hedges, or woodland clearings. Leucopaxillus giganteus contains a number of bioactive compounds, one of which has displayed antibiotic
and anti-tumor properties in laboratory tests.
in 1809, who illustrated it in his book Coloured Figures of English Fungi. Other historical synonyms include Clitocybe gigantea (Quélet
, 1872), Paxillus giganteus (Fries
, 1874), and Omphalia geotropa var. gigantea (Quélet, 1886). In 1934, Robert Kühner
and Réné Maire created the genus Astropaxillus to contain species of Leucopaxillus with smooth spores, and they set L. giganteus as its type species
. American mycologist Rolf Singer
transferred it to its current genus in 1938, but recognized the value of maintaining a distinction of the smooth-spored species, and so made L. giganteus the type species of section
Aspropaxilli.
Leucopaxillus giganteus is commonly
known as the “giant leucopax” (formerly as the “giant clitocybe”) or the “giant funnel”.
of L. giganteus can become rather large, up to 40 cm (15.7 in) in diameter with a thickness of 1 to 1.2 cm (0.393700787401575 to 0.47244094488189 in) at half the radius. Younger specimens have caps that are convex, with a margin that is rolled downwards, but as the mushrooms matures the cap flattens out and eventually becomes shallowly funnel-shaped. The cap is smooth and creamy white in color, but may develop brown stains and circular cracks with age.
The cream-colored gills are narrow, crowded close together, and have a decurrent attachment—running down the length of the stem; in age the gills will darken to a buff color. The stem
is off-white with reddish-brown fibers and has dimensions, when mature, of up to 4.5 to 6 cm (1.8 to 2.4 in) tall by 1.5 to 3 cm (0.590551181102362 to 1.2 in) thick. There is no ring
on the stem. At the base of the stem there is typically a dense, white mycelium
that may form a mat. The flesh
is firm, and also is white. Mature specimens are fragile, and difficult to remove from the ground without breaking.
, the spores
appear white. When viewed with a light microscope, the spores are ovoid to ellipsoid, translucent (hyaline
), have a smooth surface, and possess a broadly rounded apex and base; the spore dimensions are 6–8 by 3.5–5 µm
. Like all Leucopaxillus species, the spores of L. giganteus are amyloid
—meaning that they will absorb iodine
when stained with Melzer's reagent
—however, the extent of the stain may be variable. The spore-bearing cells, the basidia, are 25–40 by 4.5–8 µm, narrowly club-shaped, and are attached to either 2 or 4 spores. The hypha
e of this species invariably have clamp connection
s.
regions. Leucopaxillus septentrionalis is also large and resembles L. giganteus at some points during its development, but may be distinguished by its nauseous odor, the tan
color of the cap, and the adnate (gill squarely attached to the stem) to slightly adnexed (narrowly attached) gills. Leucopaxillus candidus tends to be smaller, with a cap diameter ranging from 6 to 20 cm (2.4 to 7.9 in) broad. Both Leucopaxillus gentianeus
and Lactarius vellereus
have been suggested as additional lookalike species. Young specimens of Leucopaxillus giganteus may be confused with Clitocybe irina, C. praemagna or C. robusta. White Lactarius
and Russula
species may also appear superficially similar, but they have brittle flesh that breaks cleanly, unlike the fibrous flesh of Leucopaxillus giganteus.
s in grassy areas like pastures, and is also found along roadsides; it produces fruiting bodies in summer and autumn. It is a saprobic species, and so derives nutrients by decomposing organic matter.
The fungus has a cosmopolitan distribution
, and occurs throughout the temperate
zone of the northern hemisphere. It is found in North America, Britain, and Europe. David Arora
reports that in North America, it is most common in the Pacific Northwest
and the Rocky Mountains
.
or similar to fish meal
; the taste and smell of the mushroom have also been alternately characterized as "mild and pleasant" or "truly disgusting". The species is also a favorite food for species of the fruit fly genus Drosophila
.
activity against a number of bacteria that are pathogen
ic to humans, such as Bacillus cereus
and Bacillus subtilis
; an earlier (1945) study showed antibiotic activity against Mycobacterium tuberculosis
, Salmonella typhi, and Brucea abortus. Clitocine has also been shown to promote apoptosis
(cell death) in human cervical cancer cells in vitro (HeLa
). The mycelia of L. giganteus, when grown in liquid culture, has been shown to produce phenols
and flavonoid
s that have antioxidant
activity.
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 giant leucopax (formerly as the giant clitocybe) or the giant funnel, is a saprobic 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 Tricholomataceae
Tricholomataceae
The Tricholomataceae are a large family of mushrooms within the Agaricales. A classic "wastebasket taxon", the Tricholomataceae is inclusive of any white-, yellow-, or pink-spored genera in the Agaricales not already classified as belonging to the Amanitaceae, Lepiotaceae, Hygrophoraceae,...
family. As its common names imply, 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...
, or mushroom, can become quite large—the 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...
reaches diameters of up to 40 cm (15.7 in). It has a white or pale cream cap, and is funnel-shaped when mature, with the gills running down the length of 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...
. Considered by some to be a choice 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...
when young, this species has a cosmopolitan distribution
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
, and is typically found growing in groups or rings
Fairy ring
A fairy ring, also known as fairy circle, elf circle, elf ring or pixie ring, is a naturally occurring ring or arc of mushrooms. The rings may grow to over in diameter, and they become stable over time as the fungus grows and seeks food underground. They are found mainly in forested areas, but...
in grassy pastures, roadside hedges, or woodland clearings. Leucopaxillus giganteus contains a number of bioactive compounds, one of which has displayed antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
and anti-tumor properties in laboratory tests.
Taxonomy
The species was first described as Agaricus giganteus by English naturalist James SowerbyJames Sowerby
James Sowerby was an English naturalist and illustrator. Contributions to published works, such as A Specimen of the Botany of New Holland or English Botany, include his detailed and appealing plates...
in 1809, who illustrated it in his book Coloured Figures of English Fungi. Other historical synonyms include Clitocybe gigantea (Quélet
Lucien Quélet
thumb|Lucien QuéletLucien Quélet was a French mycologist and naturalist who discovered several species and was the founder of the Société mycologique de France, a society devoted to mycological studies....
, 1872), Paxillus giganteus (Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
, 1874), and Omphalia geotropa var. gigantea (Quélet, 1886). In 1934, Robert Kühner
Robert Kühner
Robert Kühner, born Paris 15 March 1903, died Lyon 27 February 1996, was a French mycologist most notable for reviewing many agaric genera.-References:...
and Réné Maire created the genus Astropaxillus to contain species of Leucopaxillus with smooth spores, and they set L. giganteus as its type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
. American mycologist Rolf Singer
Rolf Singer
Rolf Singer was a German-born mycologist and one of the most important taxonomists of gilled mushrooms in the 20th century....
transferred it to its current genus in 1938, but recognized the value of maintaining a distinction of the smooth-spored species, and so made L. giganteus the type species of section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...
Aspropaxilli.
Leucopaxillus giganteus 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 “giant leucopax” (formerly as the “giant clitocybe”) or the “giant funnel”.
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. giganteus can become rather large, up to 40 cm (15.7 in) in diameter with a thickness of 1 to 1.2 cm (0.393700787401575 to 0.47244094488189 in) at half the radius. Younger specimens have caps that are convex, with a margin that is rolled downwards, but as the mushrooms matures the cap flattens out and eventually becomes shallowly funnel-shaped. The cap is smooth and creamy white in color, but may develop brown stains and circular cracks with age.
The cream-colored gills are narrow, crowded close together, and have a decurrent attachment—running down the length of the stem; in age the gills will darken to a buff color. 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 off-white with reddish-brown fibers and has dimensions, when mature, of up to 4.5 to 6 cm (1.8 to 2.4 in) tall by 1.5 to 3 cm (0.590551181102362 to 1.2 in) thick. There is no ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
on the stem. At the base of the stem there is typically a dense, white mycelium
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
that may form a mat. 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 firm, and also is white. Mature specimens are fragile, and difficult to remove from the ground without breaking.
Microscopic characteristics
When viewed in deposit, such as with a 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...
, the spores
Basidiospore
A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...
appear white. When viewed with a light microscope, the spores are ovoid to ellipsoid, translucent (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...
), have a smooth surface, and possess a broadly rounded apex and base; the spore dimensions are 6–8 by 3.5–5 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...
. Like all Leucopaxillus species, the spores of L. giganteus are amyloid
Amyloid
Amyloids are insoluble fibrous protein aggregates sharing specific structural traits. Abnormal accumulation of amyloid in organs may lead to amyloidosis, and may play a role in various neurodegenerative diseases.-Definition:...
—meaning that they will absorb iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
when stained with Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
—however, the extent of the stain may be variable. The spore-bearing cells, the basidia, are 25–40 by 4.5–8 µm, narrowly club-shaped, and are attached to either 2 or 4 spores. 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 of this species invariably have 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.
Similar species
Leucopaxillus giganteus somewhat resembles Leucopaxillus candidus, but this latter species has a darker coloring and is found more commonly in montaneMontane
In biogeography, montane is the highland area located below the subalpine zone. Montane regions generally have cooler temperatures and often have higher rainfall than the adjacent lowland regions, and are frequently home to distinct communities of plants and animals.The term "montane" means "of the...
regions. Leucopaxillus septentrionalis is also large and resembles L. giganteus at some points during its development, but may be distinguished by its nauseous odor, the tan
Tan (color)
Tan is a pale whiteish, tawny shade of white. The name is derived from tannum used in the tanning of leather.The first recorded use of tan as a shade name in English was in the year 1590....
color of the cap, and the adnate (gill squarely attached to the stem) to slightly adnexed (narrowly attached) gills. Leucopaxillus candidus tends to be smaller, with a cap diameter ranging from 6 to 20 cm (2.4 to 7.9 in) broad. Both Leucopaxillus gentianeus
Leucopaxillus gentianeus
Leucopaxillus gentianeus is a bitter-tasting, inedible mushroom commonly known as the bitter false funnelcap, or the bitter brown leucopaxillus. A common synonym is Leucopaxillus amarus. The bitter taste is caused by a triterpene called cucurbitacin B. -Description:The cap typically measures from 5...
and Lactarius vellereus
Lactarius vellereus
Lactarius vellereus, commonly known as the fleecy milk-cap, is a very large fungus in the milk-cap genus Lactarius. It is one of the two most common milk-caps found with beech trees, with the other being L. subdulcis.-Description:...
have been suggested as additional lookalike species. Young specimens of Leucopaxillus giganteus may be confused with Clitocybe irina, C. praemagna or C. robusta. White 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 Russula
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...
species may also appear superficially similar, but they have brittle flesh that breaks cleanly, unlike the fibrous flesh of Leucopaxillus giganteus.
Habitat and distribution
Leucopaxillus giganteus can form fairy ringFairy ring
A fairy ring, also known as fairy circle, elf circle, elf ring or pixie ring, is a naturally occurring ring or arc of mushrooms. The rings may grow to over in diameter, and they become stable over time as the fungus grows and seeks food underground. They are found mainly in forested areas, but...
s in grassy areas like pastures, and is also found along roadsides; it produces fruiting bodies in summer and autumn. It is a saprobic species, and so derives nutrients by decomposing organic matter.
The fungus has a cosmopolitan distribution
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
, and occurs throughout the temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
zone of the northern hemisphere. It is found in North America, Britain, and Europe. David Arora
David Arora
David Arora is an American mycologist, naturalist, and writer. He is the author of two popular books on mushroom identification, Mushrooms Demystified and All That the Rain Promises and More.......
reports that in North America, it is most common in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
and the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
.
Edibility
Although one source claims that the species is a "choice edible when young", another source warns of the possibility of stomach cramps and diarrhea. Burrows suggests preparing specimens by cutting them up and boiling the pieces, and disposing the water; then they may be used in dishes such as stews and casseroles. Because of its large size, one specimen can be enough to be consumed by several individuals. The odor has been said to be farinaceousFlour
Flour is a powder which is made by grinding cereal grains, other seeds or roots . It is the main ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history...
or similar to fish meal
Fish meal
Fish meal, or fishmeal, is a commercial product made from both whole fish and the bones and offal from processed fish. It is a brown powder or cake obtained by rendering pressing the cooked whole fish or fish trimmings to remove most of the fish oil and water, and then ground...
; the taste and smell of the mushroom have also been alternately characterized as "mild and pleasant" or "truly disgusting". The species is also a favorite food for species of the fruit fly genus Drosophila
Drosophila
Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...
.
Bioactive compounds
Leucopaxillus giganteus contains a bioactive compound named clitocine that has antibioticAntibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
activity against a number of bacteria that are pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
ic to humans, such as Bacillus cereus
Bacillus cereus
Bacillus cereus is an endemic, soil-dwelling, Gram-positive, rod-shaped, beta hemolytic bacterium. Some strains are harmful to humans and cause foodborne illness, while other strains can be beneficial as probiotics for animals...
and Bacillus subtilis
Bacillus subtilis
Bacillus subtilis, known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium commonly found in soil. A member of the genus Bacillus, B. subtilis is rod-shaped, and has the ability to form a tough, protective endospore, allowing the organism to tolerate...
; an earlier (1945) study showed antibiotic activity against Mycobacterium tuberculosis
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a pathogenic bacterial species in the genus Mycobacterium and the causative agent of most cases of tuberculosis . First discovered in 1882 by Robert Koch, M...
, Salmonella typhi, and Brucea abortus. Clitocine has also been shown to promote apoptosis
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
(cell death) in human cervical cancer cells in vitro (HeLa
HeLa
A HeLa cell is a cell type in an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken on February 8, 1951 from Henrietta Lacks, a patient who eventually died of her cancer on October 4, 1951...
). The mycelia of L. giganteus, when grown in liquid culture, has been shown to produce phenols
Natural phenol
Natural phenols, bioavailable phenols, plant phenolics, low molecular weight phenols or phenoloids are a class of natural products. They are small molecules containing one or more phenolic group. These molecules are smaller in size than polyphenols, containing less than 12 phenolic groups...
and flavonoid
Flavonoid
Flavonoids , are a class of plant secondary metabolites....
s that have antioxidant
Polyphenol antioxidant
A polyphenol antioxidant is a type of antioxidant containing a polyphenolic substructure. Numbering over 4,000 distinct species, many of these compounds have antioxidant activity in vitro but are unlikely to have antioxidant roles in vivo...
activity.