Urnula craterium
Encyclopedia
Urnula craterium is a species of cup fungus
in the family Sarcosomataceae
. It is parasitic on oak
and various other hardwood
species; it is also saprobic, as the fruit bodies
develop on dead wood after it has fallen to the ground. Appearing in early spring, its distinctive goblet-shaped and dark-colored fruit bodies have earned it the common name
s devil's urn and the gray urn. The distribution of U. craterium includes eastern North America, Europe, and Asia. It produces bioactive
compounds that can inhibit the growth of other fungi. The asexual (imperfect), or conidial
stage of U. craterium is a plant pathogen known as Conoplea globosa, which causes a canker
disease of oak
and several other hardwood
tree species.
in 1822 by American botanist Lewis David de Schweinitz as Peziza craterium, based on a specimen found in North Carolina
. The species first appeared in the scientific literature under its current name when Elias Magnus Fries
described the new genus Urnula
in 1849, and set Peziza craterium as the type species
. In 1896, German mycologist Heinrich Rehm
removed the species from Urnula – transferring it to the genus Geopyxis
– and replaced the type species with Urnula terrestris, a peripherally related species. This restructuring resulted in a taxomically
untenable situation in which the genus Urnula consisted of a single species with ambiguous resemblance to the original species (described by Fries) upon which the genus was based. According to Elsie Kupfer, who had written Rehm to clarify the rationale for his decision:
As Kupfer explains, Rehm did not justify why he believed Urnula craterium should be allied to Geopyxis, or why Podophacidium terrestre should be considered an Urnula. Kupfer's macro- and microscopic analysis of tissues from these and related genera clearly showed the inconsistency in Rehm's taxonomical choices, and that Urnula craterium represented an entirely different genus not related to Geopyxis; Fries's naming was restored.
The genus
name means "little urn
"; the specific epithet is derived from the Latin
cratera
, referring to a type of bowl used in antiquity to mix wine with water. It is commonly known
as the devil's urn and the gray urn.
begin from dense, black mycelium
on the surface of oak
branches in contact with the ground. Starting out as rolls of cylindrical tissue 1 or more centimeters long and 3–4 mm wide, they expand slowly over the winter, and grow rapidly in the spring when the weather becomes warmer.
The goblet-shaped fruit body (technically an ascocarp
) is 3 – in diameter and 4 – deep; initially it is closed, but opens as it matures, leaving a ragged or smooth inrolled margin around a round opening. The flesh
of the ascocarp walls is tough and initially gelatinous, later becoming leathery. The exterior of the ascocarp is brownish black to black, with a velvety surface, while the interior spore-bearing surface, the hymenium
, is brownish black in color, usually somewhat paler than the outside. The outer surface may be partially covered with small flakelike patches of tissue. When viewed with a magnifying glass
, the "hairs" (fungal hypha
e) making up the outer velvety surface are variable in length, and are thick-walled, blunt, and appear to wind from side to side (flexuous). The ascocarp is connected to a stalk
that is typically 3 – long by 0.4 – thick, with black mycelia at its base.
are ellipsoid or sausage-shaped (allantoid), smooth, and thin-walled. They are non-amyloid
(not taking up iodine stain
), and hyaline
(translucent), with dimensions of 22–37 by 10–15 µm
. The spore-bearing cells, the asci
are eight-spored, cylindrical, and measure 600 by 15–17 µm. They are operculate
, analogous to having a flip-top lid mechanism to release the spores. Interspersed among the asci are thin, filamentous, branched paraphyses
that extend beyond the tops of the asci.
Viewed with a microscope
, the wall of the apothecium is made of three tissue layers of roughly equal thickness. The first layer of tissue is black, leathery and compact, and covered with a fine layer of brownish-black hairs (a tomentum); the second layer consists of loosely interlaced brown hypha
e suspended in a gelatinous matrix. The third layer is the fertile, spore-bearing surface, the brownish-black hymenium
.
of Urnula craterium allows for both an imperfect (making asexual spores, or conidia
) or perfect (making sexual spores) form; as has often happened in fungal taxonomy
, the imperfect form was given a different name, because the relationship between the perfect and imperfect forms of the same species was not then known. The imperfect stage of Urnula craterium is the plant pathogenic species Conoplea globosa, known to cause a canker
disease (Strumella canker) of oak
and several other hardwood
s.
s as inedible, or not recommended for consumption due to its tough texture. Michael Kuo, in his 2007 book on edible mushrooms, lists the taste as "mediocre", and comments "the devil's urn is not as bad as I thought it was going to be. It's not good, mind you, but it would be possible to eat it with a forced smile if your Aunt Wanda served it to you."
of U. craterium have a rapid and high percentage of germination. Germination requires only 1.5 hours, a relatively short time compared to another inoperculate species in the same family
, Sarcoscypha coccinea, which requires 48 hours. Furthermore, germination is possible under a wide temperature range, from 5 °C (41 °F) to 35 °C (95 °F), and wide soil pH
range; the quality and quantity of light does not affect germination, although prolonged exposure to light does reduce germination efficiency.
) that are partially buried in the ground. The teleomorph
state is saprobic, and decomposes hardwood; the anamorph state is parasitic
, and causes a canker
of various hardwood
s, including oaks, hickories, basswood and beech
. The is often found in deciduous
forests, although it is sometimes inconspicuous due to its dark color, and because it may be partially covered with leaf litter. One of the first fleshy fungi to appear from March to May, U. craterium has been dubbed a "harbinger of spring", and is sometimes encountered under melting snow.
The distribution of U. craterium includes eastern North America, Europe (including the Czech Republic, Finland, Spain,) Japan, and China. It is red-listed
as critically endangered in the Czech Republic
.
; specifically, these chemical are antagonistic to aspen blue-stain fungi Ophiostoma crassivaginatum and O. piliferum, as well as the wood-decay fungus
Phellinus tremulae. Chemicals produced by U. craterium include pestalotin, 5,6-dehydropestalotin, 4-methoxy-3,5-dimethyl-pyran-2-one, and (4S)-3,4-dihydro-4,8-dihydroxy-1(2H)-napthalenone. However, none of these isolated compounds inhibits the aspen pathogens in vitro
, suggesting the true nature of the antifungal mechanism in the devil's urn has not yet been resolved.
Cup fungus
The Pezizaceae are a family of fungi in the Ascomycota which produce mushrooms that tends to grow in the shape of a "cup". Spores are formed on the inner surface of the fruit body . The cup shape typically serves to focus raindrops into splashing spores out of the cup...
in the family Sarcosomataceae
Sarcosomataceae
The Sarcosomataceae are a family of fungi in the order Pezizales. According to a 2008 estimate, the family contains 10 genera and 57 species. Most species are found in temperate areas, and are typically saprobic on rotten or buried wood....
. It is parasitic on 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...
and various other 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...
species; it is also saprobic, as the fruit bodies
Sporocarp (fungi)
In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...
develop on dead wood after it has fallen to the ground. Appearing in early spring, its distinctive goblet-shaped and dark-colored fruit bodies have earned it the common name
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...
s devil's urn and the gray urn. The distribution of U. craterium includes eastern North America, Europe, and Asia. It produces bioactive
Biological activity
In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or pharmacophore but can be modified by the other...
compounds that can inhibit the growth of other fungi. The asexual (imperfect), or conidial
Conidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
stage of U. craterium is a plant pathogen known as Conoplea globosa, which causes a canker
Canker
Canker and anthracnose are general terms for a large number of different plant diseases, characterised by broadly similar symptoms including the appearance of small areas of dead tissue, which grow slowly, often over a period of years. Some are of only minor consequence, but others are ultimately...
disease of 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...
and several other 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...
tree species.
History and taxonomy
Urnula craterium 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...
in 1822 by American botanist Lewis David de Schweinitz as Peziza craterium, based on a specimen found in 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...
. The species first appeared in the scientific literature under its current name when Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
described the new genus Urnula
Urnula
Urnula is a genus of fungi in the family Sarcosomataceae, circumscribed by Elias Magnus Fries in 1849. The genus contains six species found in Europe and North America....
in 1849, and set Peziza craterium as the 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...
. In 1896, German mycologist Heinrich Rehm
Heinrich Rehm
Heinrich Simon Ludwig Friedrich Felix Rehm was a German mycologist and lichenologist.-Publications:*Rehm, H. 1874. Ascomyceten Fasc. 5: 201-250*----. 1875. Ascomyceten 6: 251-300...
removed the species from Urnula – transferring it to the genus Geopyxis
Geopyxis
Geopyxis is a genus of fungi in the family Pyronemataceae. The genus has a widespread distribution and contains seven species....
– and replaced the type species with Urnula terrestris, a peripherally related species. This restructuring resulted in a taxomically
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
untenable situation in which the genus Urnula consisted of a single species with ambiguous resemblance to the original species (described by Fries) upon which the genus was based. According to Elsie Kupfer, who had written Rehm to clarify the rationale for his decision:
Urnula craterium was placed with its related species under Geopyxis, because Geopyxis was established by Persoon before Urnula by Fries; and that in order to retain the genus Urnula, under which Saccardo had placed Podophacidium terrestre of Niessl, he (Rehm) restricted the genus to this latter fungus.
As Kupfer explains, Rehm did not justify why he believed Urnula craterium should be allied to Geopyxis, or why Podophacidium terrestre should be considered an Urnula. Kupfer's macro- and microscopic analysis of tissues from these and related genera clearly showed the inconsistency in Rehm's taxonomical choices, and that Urnula craterium represented an entirely different genus not related to Geopyxis; Fries's naming was restored.
The genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name means "little urn
Urn
An urn is a vase, ordinarily covered, that usually has a narrowed neck above a footed pedestal. "Knife urns" placed on pedestals flanking a dining-room sideboard were an English innovation for high-style dining rooms of the late 1760s...
"; the specific epithet 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...
cratera
Krater
A krater was a large vase used to mix wine and water in Ancient Greece.-Form and function:...
, referring to a type of bowl used in antiquity to mix wine with water. 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 devil's urn and the gray urn.
Description
The fruit bodiesSporocarp (fungi)
In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...
begin from dense, black 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...
on the surface of 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...
branches in contact with the ground. Starting out as rolls of cylindrical tissue 1 or more centimeters long and 3–4 mm wide, they expand slowly over the winter, and grow rapidly in the spring when the weather becomes warmer.
Ascocarp
An ascocarp, or ascoma , is the fruiting body of an ascomycete fungus. It consists of very tightly interwoven hyphae and may contain millions of asci, each of which typically contains eight ascospores...
) is 3 – in diameter and 4 – deep; initially it is closed, but opens as it matures, leaving a ragged or smooth inrolled margin around a round opening. 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....
of the ascocarp walls is tough and initially gelatinous, later becoming leathery. The exterior of the ascocarp is brownish black to black, with a velvety surface, while the interior spore-bearing surface, the hymenium
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
, is brownish black in color, usually somewhat paler than the outside. The outer surface may be partially covered with small flakelike patches of tissue. When viewed with a magnifying glass
Magnifying glass
A magnifying glass is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle ....
, the "hairs" (fungal 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) making up the outer velvety surface are variable in length, and are thick-walled, blunt, and appear to wind from side to side (flexuous). The ascocarp is connected to a stalk
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...
that is typically 3 – long by 0.4 – thick, with black mycelia at its base.
Microscopic features
The sporesAscospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
are ellipsoid or sausage-shaped (allantoid), smooth, and thin-walled. They are non-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:...
(not taking up iodine stain
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...
(translucent), with dimensions of 22–37 by 10–15 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...
. The spore-bearing cells, the asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
are eight-spored, cylindrical, and measure 600 by 15–17 µm. They are operculate
Operculum (botany)
An operculum, in botany, is a term generally used to describe a structure within a plant, moss, or fungus acting as a cap, flap, or lid. In plants, it may also be called a bud cap.Examples of structures identified as opercula include:...
, analogous to having a flip-top lid mechanism to release the spores. Interspersed among the asci are thin, filamentous, branched paraphyses
Paraphyses
Paraphyses are part of the fertile spore-bearing layer in certain fungi. More specifically, paraphyses are sterile filamentous hyphal end cells composing part of the hymenium of Ascomycota and Basidiomycota interspersed among either the asci or basidia respectively, and not sufficiently...
that extend beyond the tops of the asci.
Viewed with a microscope
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
, the wall of the apothecium is made of three tissue layers of roughly equal thickness. The first layer of tissue is black, leathery and compact, and covered with a fine layer of brownish-black hairs (a tomentum); the second layer consists of loosely interlaced brown 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 suspended in a gelatinous matrix. The third layer is the fertile, spore-bearing surface, the brownish-black hymenium
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
.
Imperfect state
The life cycleBiological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
of Urnula craterium allows for both an imperfect (making asexual spores, or conidia
Conidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
) or perfect (making sexual spores) form; as has often happened in fungal taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
, the imperfect form was given a different name, because the relationship between the perfect and imperfect forms of the same species was not then known. The imperfect stage of Urnula craterium is the plant pathogenic species Conoplea globosa, known to cause a canker
Canker
Canker and anthracnose are general terms for a large number of different plant diseases, characterised by broadly similar symptoms including the appearance of small areas of dead tissue, which grow slowly, often over a period of years. Some are of only minor consequence, but others are ultimately...
disease (Strumella canker) of 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...
and several other 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.
Edibility
This species is often listed in field guideField guide
A field guide is a book designed to help the reader identify wildlife or other objects of natural occurrence . It is generally designed to be brought into the 'field' or local area where such objects exist to help distinguish between similar objects...
s as inedible, or not recommended for consumption due to its tough texture. Michael Kuo, in his 2007 book on edible mushrooms, lists the taste as "mediocre", and comments "the devil's urn is not as bad as I thought it was going to be. It's not good, mind you, but it would be possible to eat it with a forced smile if your Aunt Wanda served it to you."
Similar species
The cup fungus Plectania melastoma is also black, but it is smaller and the cup not as deep.Spore development
The sporesAscospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
of U. craterium have a rapid and high percentage of germination. Germination requires only 1.5 hours, a relatively short time compared to another inoperculate species in the same family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, Sarcoscypha coccinea, which requires 48 hours. Furthermore, germination is possible under a wide temperature range, from 5 °C (41 °F) to 35 °C (95 °F), and wide soil pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
range; the quality and quantity of light does not affect germination, although prolonged exposure to light does reduce germination efficiency.
Ecology, habitat and distribution
Urnula craterium grows singly or clustered together, usually attached to sticks and branches (especially 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...
) that are partially buried in the ground. The teleomorph
Teleomorph, anamorph and holomorph
The terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota.*Teleomorph: the sexual reproductive stage , typically a fruiting body....
state is saprobic, and decomposes hardwood; the anamorph state is 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...
, and causes a canker
Canker
Canker and anthracnose are general terms for a large number of different plant diseases, characterised by broadly similar symptoms including the appearance of small areas of dead tissue, which grow slowly, often over a period of years. Some are of only minor consequence, but others are ultimately...
of various 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, including oaks, hickories, basswood and 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:...
. The is often found in deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
forests, although it is sometimes inconspicuous due to its dark color, and because it may be partially covered with leaf litter. One of the first fleshy fungi to appear from March to May, U. craterium has been dubbed a "harbinger of spring", and is sometimes encountered under melting snow.
The distribution of U. craterium includes eastern North America, Europe (including the Czech Republic, Finland, Spain,) Japan, and China. It is red-listed
Regional Red List
A Regional Red List is a report of the threatened status of species within a certain country or region. It is based on the IUCN Red List of Threatened Species, an inventory of the conservation status of species on a global scale...
as critically endangered in the Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
.
Bioactive compounds
Urnula craterium, when grown in liquid culture, produces bioactive chemicals that inhibit the growth of other fungi that are pathogenic to aspenAspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...
; specifically, these chemical are antagonistic to aspen blue-stain fungi Ophiostoma crassivaginatum and O. piliferum, as well as the wood-decay fungus
Wood-decay fungus
A wood-decay fungus is a variety of fungus that digests moist wood, causing it to rot. Some wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria , are parasitic and colonize living trees. Fungi that not only grow on wood but actually cause it to decay, are called...
Phellinus tremulae. Chemicals produced by U. craterium include pestalotin, 5,6-dehydropestalotin, 4-methoxy-3,5-dimethyl-pyran-2-one, and (4S)-3,4-dihydro-4,8-dihydroxy-1(2H)-napthalenone. However, none of these isolated compounds inhibits the aspen pathogens in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
, suggesting the true nature of the antifungal mechanism in the devil's urn has not yet been resolved.