''Uncobasidium'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of two species of

crust 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 ...

in the

Meruliaceae The Meruliaceae are a family of fungi in the order Polyporales. According to a 2008 estimate, the family contains 47 genera and 420 species. , Index Fungorum accepts 645 species in the family. Taxonomy The family was formally circumscribed by E ...

family . The genus was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

by mycologists Kurt Hjorstam and

Leif Ryvarden Leif Randulff Ryvarden (born 9 August 1935) is a Norwegian mycologist. Early life and education Leif Ryvarden was born in Bergen as a son of Einar Norberg Johansen (1900–1959) and Hjørdis Randulff (1912–1975). He finished his secondary ed ...

in 1978 with the European fungus '' U. luteolum'' as the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

. The South American species '' U. roseocremeum'' was added to the genus in 2012. The distinguishing feature of ''Uncobasidium'' is the basal hook in the

basidium A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

Description

''Uncobasidium'' forms a crust-like

fruit body 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 cyc ...

, which is spread out on the surface of the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

. Its texture is softly membranous or byssoid (as if made of fibers). The

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 ...

l system is monomitic, meaning it contains only generative hyphae. Individual hyphae are distinct when viewed with microscopy, and they range from thin to becoming thick walled, with

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

. The hyphae of the subiculum are usually straight and of uniform diameter. In contrast, the hyphae of the subhymenium are twisty and sometimes strongly bent. The

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

(pleurobasidia) are roughly uniform (swollen at the base). They are strongly constricted with a hook-shaped appendage, arising in the basal

septum In biology, a septum (Latin language, Latin for ''something that encloses''; septa) is a wall, dividing a Body cavity, cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Hum ...

, with four

sterigmata In biology, a sterigma (: sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the tip ...

. The

spores In biology, a spore is a unit of sexual (in fungi) 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 plant ...

of ''Uncobasidium'' fungi are

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

obovate The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets) ...

in shape, thin walled, and non-

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

Species

*'' Uncobasidium luteolum'' Hjortstam & Ryvarden (1978) *'' Uncobasidium roseocremeum'' Gorjón, Gresl. & Rajchenb. (2013) Some species proposed for inclusion in ''Uncobasidium'' have been referred to other genera, including: *''Uncobasidium albidum'' (Hauerslev) Vesterh. (1996) = ''

Aphanobasidium albidum ''Aphanobasidium'' is a genus of corticioid or crust fungi in the Radulomycetaceae family. The genus has a widespread distribution and contains several species. This genus was formally considered to be part of the ''Pterulaceae'' family. A maj ...

'' (Hauerslev) Boidin & Gilles (1980) *''Uncobasidium calongei'' (Tellería) Hjortstam & Tellería (1990) = ''

Cerocorticium calongei ''Cerocorticium'' is a genus of seven species of crust fungi in the family Meruliaceae. Taxonomy The genus was circumscribed by German mycologist Paul Christoph Hennings in 1900, as a member of the family Thelephoraceae. Hennings included two s ...

'' Tellería (1985) *''Uncobasidium notabile'' (H.S.Jacks.) Tellería (1995) = '' Radulomyces notabilis'' (H.S.Jacks.) Parmasto (1968)

References

{{Taxonbar, from=Q7882863 Meruliaceae Polyporales genera Taxa named by Leif Ryvarden Taxa described in 1978