''Omphalotus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is t ...

, in the family

Marasmiaceae The Marasmiaceae are a family of basidiomycete fungi which have white spores. They mostly have tough stems and the capability of shrivelling up during a dry period and later recovering. The widely consumed edible fungus ''Lentinula edodes'', the ...

, formally

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

Victor Fayod Victor Fayod (23 November 1860 – 28 April 1900) was a Swiss mycologist, who created an influential novel classification of the agaric fungi and who described a number of new genera and species. Biographical overview Fayod was born on 23 Nove ...

in 1889. Members have the traditional

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

and

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

structure. They are

saprobic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...

, and fruit in clumps on the ground, adjacent to host trees. The best known and

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is the jack-o'-lantern mushroom ''(

Omphalotus olearius ''Omphalotus olearius'',Singer R (1948) In: ''Pap. Mich. Acad. Sci.'' 32: 133 ('1946'). commonly known as the jack-o'-lantern mushroom, is a poisonous Orange (color), orange gilled mushroom that to an untrained eye appears similar to some Cantha ...

)''. Species of ''Omphalotus'' have been mistaken for

chanterelle Chanterelle is the common name of several species of fungi in the genera '' Cantharellus'', '' Craterellus'', '' Gomphus'', and ''Polyozellus''. They are among the most popular of wild edible mushrooms. They are orange, yellow or white, meaty a ...

s. All ''Omphalotus'' species are presumed

poisonous Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

, causing gastrointestinal symptoms. Some ''Omphalotus'' species have

bioluminescent Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorganisms including ...

properties.

Taxonomy

Victor Fayod originally erected the genus with '' Pleurotus olearius'' and '' P. eryngii'' as its principal species in 1889, placing it in a ''tribus'' ("alliance") with the genera ''

Pleurotus ''Pleurotus'' is a genus of gilled mushrooms which includes one of the most widely eaten mushrooms, '' P. ostreatus''. Species of ''Pleurotus'' may be called oyster, abalone, or tree mushrooms, and are some of the most commonly cultivated edib ...

'' and '' Pleurotellus''. The relationships of the genus have become clearer with genetic analysis.

Rolf Singer Rolf Singer (June 23, 1906 – January 18, 1994) was a Germany, German-born mycologist and one of the most important Taxonomy (biology), taxonomists of gilled mushrooms (agarics) in the 20th century. After receiving his Ph.D. at the University ...

placed it and the related ''Lampteromyces'' in the

Boletales The Boletales are an order of Agaricomycetes containing over 1300 species with a diverse array of fruiting body types. The boletes are the best known members of this group, and until recently, the Boletales were thought to only contain boletes. T ...

due to the presence of the pigment

variegatic acid Variegatic acid (3,3',4,4'-tetrahydroxypulvinic acid) is an orange pigment found in some mushrooms. It is responsible for the bluing reaction seen in many bolete mushrooms when they are injured. When mushroom tissue containing variegatic acid is e ...

. More specifically the genera were placed in the family

Paxillaceae The Paxillaceae are a family of mushroom-forming fungi bearing close affinity to the boletes. Collectively, the family contains nine genera and 78 species. The type genus is ''Paxillus'', containing fungi with decurrent gills, and ''Gyrodon'', ...

. However, it was found that fungi of the genus ''Omphalotus'' break down

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity ...

while those of the genus ''

Paxillus ''Paxillus'' is a genus of mushrooms of which most are known to be poisonous or inedible. Species include '' Paxillus involutus'' and '' Paxillus vernalis''. Two former species—''Tapinella panuoides'' and ''Tapinella atrotomentosa''—have now ...

'' break down

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...

. Since then, the genera have been found to have a close relationship with the genus '' Nothopanus'', and the whole group to lie within the agaric family

. The group has been classified in their own family Omphalotaceae. The

is the jack-o'-lantern mushroom ''(

)'' from Europe. Another eight species have been described. The seven species examined genetically form two

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

s. One is an ''illudens'' clade containing ''( O. illudens)'' of Europe and North America, and ''( O. mexicanus)'' from Central America. The other is an ''olearius'' clade containing ''O. olearius'' and the tsukiyotake ''( O. japonicus)'' from eastern Asia as sister species, and the western jack-o'-lantern ''( O. olivascens)'' and ''( O. subilludens)''. Since the phylogeny was published, '' Omphalotus flagelliformis'' has been described from

Yunnan Province Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the C ...

in China, which is related to ''O. mexicanus'' and ''O. illudens''. The generic name ''Omphalotus'' is derived from the

Byzantine Greek Medieval Greek (also known as Middle Greek, Byzantine Greek, or Romaic) is the stage of the Greek language between the end of classical antiquity in the 5th–6th centuries and the end of the Middle Ages, conventionally dated to the Ottoman co ...

ὀμϕαλοειδής, meaning "navel".

Phylogeny

Species

Description

Fungi of this genus produce fleshy mushrooms with smooth or fibrous

caps Caps are flat headgear. Caps or CAPS may also refer to: Science and technology Computing * CESG Assisted Products Service, provided by the U.K. Government Communications Headquarters * Composite Application Platform Suite, by Java Caps, a Java ...

with

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

and fleshy or fibrous stems growing in clumps on wood. ''O. mexicanus'' has dark blue fruiting bodies tinted with yellow.

Toxicity

Many members of the genus are known to be toxic, with consumption leading to gastrointestinal symptoms of nausea, vomiting and at times diarrhea. The toxic ingredient is a

sesquiterpene Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificatio ...

compound known as

illudin The illudins are a family of sesquiterpenes with antitumor antibiotic properties produced by some mushrooms. In their isolated form, illudins show selective toxicity for myelocytic leukemia and other carcinoma cells. Illudins are highly toxic, w ...

Distribution and ecology

The genus has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

, found in forests around the world. Its species cause a white soft rot on dead wood as they break down

References

External links

MushroomExpert.com

Blog - Mycology
{{Taxonbar, from=Q2521208 Omphalotus, Agaricales genera