''Rhodonia'' is a fungal

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 nom ...

in the family Fomitopsidaceae. It is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

genus, containing the single

crust fungus 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 p ...

''Rhodonia placenta''. A brown rot species, ''R. placenta'' is found in China, Europe, and North America, where it grows on decaying conifer wood.

Taxonomy

The genus was

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 ...

by Finnish mycologist Tuomo Niemelä in 2005 to contain the single species ''Rhodonia placenta''. This

has undergone several changes in generic placement since it was originally described as a species of ''

Polyporus ''Polyporus'' is a genus of poroid fungi in the family Polyporaceae. Taxonomy Italian botanist Pier Antonio Micheli introduced the genus in 1729 to include 14 species featuring fruit bodies with centrally-placed stipes, and pores on the under ...

'' by Elias Magnus Fries in 1861. Although often placed in '' Oligoporus'' or '' Postia'', molecular analysis has revealed that this species is phylogenetically distant from those genera, appearing instead in a separate clade near '' Antrodia''.

Synonymy

''Rhodonia placenta'' has acquired an extensive

synonymy A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

in its taxonomic history. In addition to having been transferred to several polypore genera, it is considered to be the same species as ''Poria incarnata'' described by

Christian Hendrik Persoon Christiaan Hendrik Persoon (1 February 1761 – 16 November 1836) was a German mycologist who made additions to Linnaeus' mushroom taxonomy. Early life Persoon was born in South Africa at the Cape of Good Hope, the third child of an i ...

in 1794, as well as

Petter Karsten Petter Adolf Karsten (16 February 1834 – 22 March 1917) was a Finnish mycologist, the foremost expert on the fungi of Finland in his day, and known in consequence as the "father of Finnish mycology". Karsten was born in Merimasku near Turku, s ...

's ''Bjerkandera roseomaculata'' (1891), and ''Physisporus albolilacinus'' (1892). Other taxonomic synonyms include

William Alphonso Murrill William Alphonso Murrill (October 13, 1869 – December 25, 1957) was an American mycologist, known for his contributions to the knowledge of the Agaricales and Polyporaceae. In 1904, he became the assistant Curator at the New York Botanical ...

's ''Poria monticola'', Dow Baxter's ''Poria carnicolor'' (1941), and

Lee Oras Overholts Lee Oras Overholts (23 June 1890 – 10 November 1946) was an American mycologist known for his expertise on polypore fungi. Personal life Lee Oras Overholts was born in Camden, Ohio and attended Miami University, where he received a Bachelo ...

' ''Poria microspora'' (1943). *''Polyporus placenta'' Fr. (1861) *''Physisporus placenta'' (Fr.) P. Karst. (1882) *''Poria placenta'' (Fr.) Cooke (1886) *''Leptoporus placenta'' (Fr.) Pat. (1900) *''Ceriporiopsis placenta'' (Fr.) Domański (1963) *''Tyromyces placenta'' (Fr.) Ryvarden (1973) *''Oligoporus placenta'' (Fr.) Gilb. & Ryvarden (1985) *''Postia placenta'' (Fr.) M.J. Larsen & Lombard (1986) *''Poria incarnata'' Pers. (1794) *''Boletus incarnatus'' (Pers.) Pers. (1801) *''Polyporus incarnatus'' (Pers.) Fr. (1821) *''Physisporus incarnatus'' (Pers.) Gillet (1878) *''Caloporus incarnatus'' (Pers.) P.Karst. (1881) *''Caloporia incarnata'' (Pers.) P.Karst. (1898) *''Ceriporia incarnata'' (Pers.) Bondartsev (1953) *''Bjerkandera roseomaculata'' P.Karst. (1891) *''Polyporus roseomaculatus'' (P.Karst.) Sacc. (1895) *''Ceriporiopsis placenta'' f. ''roseomaculata'' (P.Karst.) Domański (1965) *''Physisporus albolilacinus'' P.Karst. (1892) *''Poria albolilacina'' (P.Karst.) Sacc. (1895) *''Poria monticola'' Murrill (1920) *''Poria placenta'' f. ''monticola'' (Murrill) Domański (1972) *''Poria carnicolor'' D.V.Baxter (1941) *''Poria microspora'' Overh. (1943) *''Ceriporiopsis placenta'' f. ''microspora'' Domański (1965)

Description

The ''Rhodonia''

fruit body In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is spread out (effused) on its substrate, poroid, fairly thick, juicy and soft, with a pale rose or white colouring. It has a monomitic hyphal system (containing only generative hyphae), and the hyphae have

clamp connection 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), rec ...

s. These hyphae are initially thin-walled but become thick-walled in mature fruit bodies. 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 cylindric.

Sequencing

''Rhodonia placenta'' had its sequenced genome published in 2009. It has an "unusual repertoire" of extracellular

glycoside hydrolase Glycoside hydrolases (also called glycosidases or glycosyl hydrolases) catalyze the hydrolysis of glycosidic bonds in complex sugars. They are extremely common enzymes with roles in nature including degradation of biomass such as cellulose (ce ...

s—secreted enzymes that break down the complex sugars found in

lignocellulose Lignocellulose refers to plant dry matter (biomass), so called lignocellulosic biomass. It is the most abundantly available raw material on the Earth for the production of biofuels. It is composed of two kinds of carbohydrate polymers, cellulose a ...

References

{{Taxonbar, from=Q10653291 Fomitopsidaceae Fungi of China Fungi of Europe Fungi of North America Monotypic Polyporales genera Taxa described in 2005