''Xerocomellus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

in the family

Boletaceae The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface (at the underside of the mushroom), instead of gills as are found in most agarics. Nearly as widely distributed ...

. The genus, as it was described in 2008, contained 12 species. However '' X. rubellus'' and '' X. engelii'' were transferred to the new genus '' Hortiboletus'' and '' X. armeniacus'' was transferred to the new genus ''

Rheubarbariboletus ''Rheubarbariboletus'' is a fungal genus in the family Boletaceae. Circumscribed in 2014, it contains two species found in Europe: ''Rheubarbariboletus persicolor'', and the type, '' R. armeniacus''. The generic name is derived from the Lati ...

'' in 2015.

Molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

analysis supports the distinction of ''Xerocomellus'' species from ''

Boletus ''Boletus'' is a genus of mushroom-producing fungi, comprising over 100 species. The genus ''Boletus'' was originally broadly defined and described by Carl Linnaeus in 1753, essentially containing all fungi with hymenial pores instead of gil ...

'' and ''

Xerocomus ''Xerocomus'' is a genus of poroid fungi related to '' Boletus''. Many mycologists did not originally recognize the distinction between the two genera and placed ''Xerocomus'' taxa in genus ''Boletus''. However, several molecular phylogenetic ...

'', within which these species were formerly contained. ''Xerocomellus'' in fact is only distantly related to ''

'' and is most closely related to ''

Tylopilus ''Tylopilus'' is a genus of over 100 species of mycorrhizal bolete fungi separated from ''Boletus''. Its best known member is the bitter bolete (''Tylopilus felleus''), the only species found in Europe. More species are found in North America, s ...

'', ''

'' sensu stricto, ''

Porphyrellus ''Porphyrellus'' is a genus of fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are c ...

'', ''

Strobilomyces ''Strobilomyces'' is a genus of boletes (mushrooms having a spongy mass of pores under the cap). The only well-known European species is the type species '' S. strobilaceus'' (also named ''S. floccopus''), known in English as "old man of the wood ...

'', and ''

Xanthoconium ''Xanthoconium'' is a genus of bolete fungi in the family Boletaceae. It was circumscribed by mycologist Rolf Singer in 1944, who included ''Boletus affinis'' and what was then known as ''Gyroporus stramineus'' as the type species. These two s ...

''.

Taxonomy

Members of the genus had been

classified Classified may refer to: General *Classified information, material that a government body deems to be sensitive *Classified advertising or "classifieds" Music *Classified (rapper) (born 1977), Canadian rapper *The Classified, a 1980s American roc ...

either in the genus ''Boletus'' or ''Xerocomus'' until Czech mycologist Josef Šutara examined a number of species and concluded that there was a defined group containing ''X. chrysenteron'', ''X. armeniacus'' and relatives that are distinct morphologically from the group containing ''

Xerocomus subtomentosus ''Xerocomus subtomentosus'', commonly known as suede bolete, brown and yellow bolete , boring brown bolete or yellow-cracked bolete, is a species of bolete fungus in the family Boletaceae. The fungus was initially described by Carl Linnaeus in 17 ...

'' and related species. He deferred fully delimiting the genus until genetic work confirmed their distinctness. Previously, Manfred Binder had coined the term ''Paraxerocomus'' for the group but this was not officially published. The

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 red-cracked bolete (''

Xerocomellus chrysenteron ''Xerocomellus chrysenteron'', formerly known as ''Boletus chrysenteron'' or ''Xerocomus chrysenteron'', is a small, edible, wild mushroom in the family Boletaceae. These mushrooms have tubes and pores instead of gills beneath their caps. It ...

'').

Genetic analysis Genetic analysis is the overall process of studying and researching in fields of science that involve genetics and molecular biology. There are a number of applications that are developed from this research, and these are also considered parts of ...

published in 2013 showed that ''X. chrysenteron'' and ''X. zelleri'' form a ''Xerocomellus'' clade within a larger group informally called "anaxoboletus" in the

Boletineae The Boletineae are a suborder of the fungal order Boletales. Families in the Boletineae include the Boletaceae and the Paxillaceae. Taxa *Paxillaceae **''Alpova'' **''Austrogaster'' **'' Gyrodon'' **''Hydnomerulius'' **'' Meiorganum'' **'' Mel ...

. It appears to have affinities with what was then known informally as the "rubellus clade", which contained the species ''X. rubellus'' and ''X. armeniacus'', now known as ''

Hortiboletus rubellus ''Hortiboletus rubellus'', commonly known as the ruby bolete, is a small, dainty, brightly coloured member of the family Boletaceae, with a reddish cap and stipe, and yellow pores. Like many boletes, it stains blue when cut or bruised. It is f ...

'' and ''

Rheubarbariboletus armeniacus ''Rheubarbariboletus armeniacus'' is a small mushroom in the family Boletaceae native to Europe. It was formerly placed in the genera ''Boletus'', ''Xerocomus'', and '' Xerocomellus''. It acquired its current name when it was transferred to genus ...

'' respectively. The same study found ''Xerocomellus'' to be more distantly to a 'badius' clade containing ''Boletus badius'', now known as '' Imleria badia'', and relatives. Other clades in the group include the porcini (true ''

'' species) and ''

'' clades, species currently designated ''

'' (the species are not true ''Xerocomus'' species), and smaller genera whose relationships are unclear.

Description

Members of the genus have small to medium-size

fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life c ...

with more slender

stipes Crucifixion is a method of capital punishment in which the victim is tied or nailed to a large wooden cross or beam and left to hang until eventual death from exhaustion and asphyxiation. It was used as a punishment by the Persians, Carthagin ...

compared with other boletes. They are often brightly coloured. The caps are dry and do not become sticky when wet. Their cuticle tissue is a palisadoderm, comprising parallel or roughly parallel

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

arranged in an

anticlinal Anticlinal may refer to: *Anticline, in structural geology, an anticline is a fold that is convex up and has its oldest beds at its core. *Anticlinal, in stereochemistry, a torsion angle between 90° to 150°, and –90° to –150°; see Alkane_st ...

fashion. The palisoderm, which is generally between 120 and 350

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...

thick (although extremes of 80 μm and 500 μm are known), maintains its characteristic arrangement for longer periods than other boletes. The tubes are generally yellow and

adnate Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins – sometimes popularly referred to as Siamese twins – are ...

or slightly

decurrent ''Decurrent'' (sometimes decurring) is a term used in botany and mycology to describe plant or fungal parts that extend downward. In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petio ...

. The pores are also yellow and quite large, up to 2.5 mm in diameter each and angular in shape. The

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

are generally spindle-shaped to oval and have a smooth or striate surface. The

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing pinkish-tan spore print. A 3.5-centimeter ...

is brown or slightly olive-tinged when fresh. Morphological Features of Xerocomoid Boletes

Ecology

''Xerocomellus'' species form mycorrhizal associations with

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

ous and

deciduous tree In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

Species

References

External links

* * {{Taxonbar, from=Q1230774 Boletaceae Boletales genera