The Hymenochaetales are an order 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 classified as a kingdom, separately from ...

in the

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differentl ...

Agaricomycetes The Agaricomycetes are a class of fungi in the division Basidiomycota. The taxon is roughly identical to that defined for the Homobasidiomycetes (alternatively called holobasidiomycetes) by Hibbett & Thorn, with the inclusion of Auriculariales a ...

. The order in its current sense is based on molecular research and not on any unifying morphological characteristics. According to one 2008 estimate, the Hymenochaetales contain around 600

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

worldwide, mostly

corticioid fungi The corticioid fungi are a group of fungi in the Basidiomycota typically having effused, smooth basidiocarps (fruit bodies) that are formed on the undersides of dead tree trunks or branches. They are sometimes colloquially called crust fungi or pa ...

and poroid fungi, but also including several

clavarioid fungi The clavarioid fungi are a group of fungi in the ''Basidiomycota'' typically having erect, simple or branched basidiocarps (fruit bodies) that are formed on the ground, on decaying vegetation, or on dead wood. They are colloquially called club fun ...

and

agarics An agaric () is a type of fungus fruiting body characterized by the presence of a pileus (cap) that is clearly differentiated from the stipe (stalk), with lamellae (gills) on the underside of the pileus. In the UK, agarics are called "mushrooms ...

. Species of economic importance include wood decay fungi in the genera '' Phellinus'' and ''

Inonotus ''Inonotus'' is a genus of fungi in the family Hymenochaetaceae. The genus, described by Petter Karsten in 1879, is estimated to contain about 80 species ''sensu lato'' and 30 species ''sensu stricto'' (in the strict sense). The name comes from ...

'' sensu lato, some of which may cause losses in forestry. Therapeutic properties are claimed for ''

Inonotus obliquus ''Inonotus obliquus'', commonly called chaga (a Latinisation of the Russian word ''чага''), is a fungus in the family Hymenochaetaceae. It is parasitic on birch and other trees. The sterile conk is irregularly formed and resembles burnt c ...

'' ("chaga") and ''

Phellinus linteus ''Phellinus linteus'' (Japanese "meshimakobu", Chinese "song gen", Korean "sanghwang", English "mesima", American English "black hoof mushroom") is a mushroom. It is shaped like a hoof, has a bitter taste, and in the wild grows on mulberry tree ...

'', both of which are now commercially marketed.

Taxonomy

History

The order was proposed in 1977 to recognize the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Hymenochaetaceae The ''Hymenochaetaceae'' are a family of fungi in the order Hymenochaetales. The family contains several species that are implicated in many diseases of broad-leaved and coniferous trees, causing heart rot, canker and root diseases, and also esc ...

at a higher

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

rank. As originally conceived, species within the Hymenochaetales had several morphological features in common, notably brown or brownish

basidiocarps In fungi, a basidiocarp, basidiome, or basidioma () is the sporocarp (fungi), sporocarp of a basidiomycota, basidiomycete, the Multicellular organism, multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are chara ...

(fruit bodies) that turn black in

alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

hyphae 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 or ...

lacking

clamp connections A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of Basidiomycetes fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

, and the presence (in most species) of characteristic

setae In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

(thick-walled, thorn-shaped

cystidia A cystidium (plural cystidia) is a relatively large cell found on the sporocarp of a basidiomycete (for example, on the surface of a mushroom gill), often between clusters of basidia. Since cystidia have highly varied and distinct shapes that ar ...

, visible under a hand lens). Subsequent

ultrastructure Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a co ...

research showed that the Hymenochaetales had dolipores with imperforate parenthesomes, whereas most Agaricomycetes have dolipores with perforate parenthesomes. Species of the

corticioid The corticioid fungi are a group of fungi in the Basidiomycota typically having effused, smooth basidiocarps (fruit bodies) that are formed on the undersides of dead tree trunks or branches. They are sometimes colloquially called crust fungi or pa ...

genera 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 nomenclat ...

Hyphodontia ''Hyphodontia'' is a genus of fungi in the family Hymenochaetaceae (Schizoporaceae in Index Fungorum ''Index Fungorum'' is an international project to index all formal names (scientific names) in the fungus kingdom. the project is based at t ...

'' and '' Schizopora'' were later found to share this peculiarity, suggesting they might also be related to the Hymenochaetales, though morphologically dissimilar.

Current status

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 bioche ...

research, based on

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis of

DNA sequences A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are usua ...

, has substantially expanded and redefined the Hymenochaetales, dividing the order into at least six different

clades 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, t ...

. The core clade represents the traditional Hymenochaetaceae, excluding the genera ''

Coltricia ''Coltricia'' is a genus of fungi in the family Hymenochaetaceae. It was circumscribed by Samuel Frederick Gray Samuel Frederick Gray (10 December 1766 – 12 April 1828) was a British botanist, mycologist, and pharmacologist. He was the fath ...

'' and ''

Coltriciella ''Coltriciella'' is a genus of fungi in the family Hymenochaetaceae. Species list

*''Coltriciella corticicola'' *''Coltriciella dependens'' *''Coltriciella navispora'' *''Coltriciella oblectabilis'' *''Coltriciella pusilla'' *''Coltriciella ...

''; another clade includes the corticioid genera '' Lyomyces'' and ''Schizopora'' (

Schizoporaceae Schizoporaceae are a family of fungi in the order Hymenochaetales. These are saprobic, and cause white rots of standing and fallen wood of coniferous and broadleaved trees. According to one 2008 estimate, the family contains 14 genera and 109 sp ...

), together with ''Coltricia'' and ''Coltriciella'' as a subclade; a further clade (

Repetobasidiaceae Repetobasidiaceae is a phylogenetically defined family encompassing resupinate, poroid, stereoid, clavarioid, and agaric An agaric () is a type of fungus fruiting body characterized by the presence of a pileus (cap) that is clearly differenti ...

) includes agaricoid '' Rickenella'' species, the clavarioid '' Alloclavaria purpurea'', and various corticioid fungi, including the genus '' Repetobasidium''; the three remaining clades consist of corticioid ''Hyphodontia'' species, corticioid '' Kneifiella'' species, and poroid '' Oxyporus'' species. Not all the species currently placed within the Hymenochaetales have dolipores with imperforate parenthosomes, so the order lacks any shared morphological characteristics. File:Inonotus-hispidus01.jpg, File:Rickenella swartzii - Lindsey 1b.jpg, File:Schizopora.paradoxa.-.lindsey.jpg, File:Coltricia perennis 01.JPG, File:Hyphodontia arguta - Lindsey.jpg,

Habitat and distribution

Most fungi within the order are saprotrophs of dead wood, but some species within the Hymenochaetaceae can cause rots of living trees. Species of ''Coltricia'' and ''Coltriciella'' are

ectomycorrhizal An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; pl. ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobi ...

. Agaricoid species of ''Rickenella'' and related genera are parasites of mosses and liverworts. Distribution of the Hymenochaetales is

cosmopolitan Cosmopolitan may refer to: Food and drink * Cosmopolitan (cocktail), also known as a "Cosmo" History * Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953 Hotels and resorts * Cosmopoli ...

Economic importance

Several wood decay fungi in the genera '' Phellinus'' and ''

'' sensu lato are pathogenic, causing losses in forestry plantations. Therapeutic properties are claimed for ''

'' ("chaga") and ''

'', both of which are commercially marketed as alternative medicines.

Genera ''incertae sedis''

Several genera in the Hymenochatales are ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'' with respect to familial placement: *'' Atheloderma'' Parmasto (1968) *'' Caeruleomyces'' Stalpers (2000) *'' Cyanotrama'' Ghob.-Nejh. & Y.C. Dai (2010) *'' Fibricium'' J.Erikss. (1958) *'' Ginnsia'' Sheng H.Wu & Hallenb. (2010) *'' Lawrynomyces'' Karasiński (2013) *'' Physodontia'' Ryvarden & H.Solheim (1977) *'' Subulicium'' Hjortstam & Ryvarden (1979) *''

Trichaptum ''Trichaptum'' is a genus of poroid fungi. The genus was circumscribed by American mycologist William Alphonso Murrill in 1904. Formerly classified in the family Polyporaceae, several molecular studies have shown that the genus belongs to the o ...

'' Murrill (1904)

References

External links

Tree of Life Web Project: Hymenochaetoid Clade
{{Taxonbar, from=Q610217 Basidiomycota orders Taxa described in 1977 Taxa named by Franz Oberwinkler