The Tremellaceae are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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

in the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Tremellales The Tremellales are an order of fungi in the class Tremellomycetes. The order contains both teleomorphic and anamorphic species, most of the latter being yeasts. All teleomorphic species in the Tremellales are parasites of other fungi, though the ...

. The family is

cosmopolitan Cosmopolitan may refer to: Internationalism * World citizen, one who eschews traditional geopolitical divisions derived from national citizenship * Cosmopolitanism, the idea that all of humanity belongs to a single moral community * Cosmopolitan ...

and contains both

teleomorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

ic and

anamorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, most of the latter being

yeasts Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitu ...

. All teleomorphs in the Tremellaceae are

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...

of other fungi, though the yeast states are widespread and not restricted to hosts.

Basidiocarps In fungi, a basidiocarp, basidiome, or basidioma () is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do no ...

(fruit bodies), when produced, are gelatinous. The family currently comprises the single genus ''

Tremella ''Tremella'' is a genus of fungi in the family (biology), family Tremellaceae. All ''Tremella'' species are parasitism, parasites of other fungi and most produce anamorphic yeast states. Basidiocarps (fruit bodies), when produced, are gelatinous ...

'', containing around 40 species. The name previously covered a much wider range of genera within the Tremellales, but

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

research, based on

cladistic Cladistics ( ; from Ancient Greek 'branch') 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 ...

analysis of

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

, now places these genera in separate families.

History

Fries French fries, or simply fries, also known as chips, and finger chips (Indian English), are ''List of culinary knife cuts#Batonnet, batonnet'' or ''Julienning, julienne''-cut deep frying, deep-fried potatoes of disputed origin. They are prepa ...

created the family Tremellaceae (as 'Tremellini') in 1821, basing it on the macromorphology of fruit bodies. He included within it most species of fungi that were gelatinous, dividing it into the genera ''

Agyrium ''Agyrium'' is a genus of saprophytic fungi in the family Agyriaceae. It probably evolved from a lichen ancestor, as it is closely related to many lichenized species of fungi. Taxonomy ''Agyrium'' was first proposed by Elias Magnus Fries in hi ...

'', ''

Dacrymyces ''Dacrymyces'' is a genus of fungi in the family Dacrymycetaceae. Species are saprotrophs and occur on dead wood. Their distribution is worldwide. Basidiocarps (fruit bodies) are ceraceous to gelatinous, often yellow to orange, and typically di ...

'', '' Exidia'', ''Hymenella'', ''Naematelia'', and ''

''. ''Agyrium'' and ''Hymenella'' are now referred to the

Ascomycota Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The def ...

, as are several of the species Fries placed in ''Dacrymyces'' and ''Tremella''. In 1900 Patouillard radically revised the family by switching the emphasis to the micromorphology of fruit bodies. For Patouillard, the Tremellaceae was limited to genera and species in which 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 ...

were "tremelloid" (globose to ellipsoid with vertical or diagonal septa), whether or not the fruit bodies were gelatinous. Patouillard's revised Tremellaceae included the genera ''Clavariopsis'' (= '' Holtermannia''), ''Ditangium'', ''Exidia'', '' Guepinia'', '' Heterochaete'', '' Hyaloria'', '' Protomerulius'', ''

Sebacina ''Sebacina'' is a genus of fungi in the family Sebacinaceae. Its species are mycorrhizal, forming a range of associations with trees and other plants. Basidiocarps (fruit bodies) are produced on soil and litter, sometimes partly encrusting stems ...

'', '' Sirobasidium'', ''Tremella'', and ''Tremellodon'' (= '' Pseudohydnum''). The next major revision was in 1984, when Robert Bandoni used

transmission electron microscopy Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a g ...

to investigate the

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 c ...

of the septal pore apparatus in species of the Tremellaceae. This revealed that ''Tremella'' and its allies were distinct from ''Exidia'' and its allies, despite both groups having tremelloid basidia. Bandoni referred the latter group to the

Auriculariaceae The Auriculariaceae are a family (biology), family of fungi in the order (biology), order Auriculariales. Species within the family were formerly referred to the "heterobasidiomycetes" or "jelly fungi", since many have gelatinous basidiocarps (fr ...

, restricting the Tremellaceae to the genera ''Holtermannia'', ''Tremella'', and '' Trimorphomyces''. The genus ''Sirobasidium'' and its allies were placed in the Sirobasidiaceae.

Current status

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

research, based on

analysis of

, confirms Bandoni's split between the tremelloid and exidioid fungi and extends the circumscription of the tremelloid group by including several yeasts whose status was formerly uncertain. It has, however, shown that the Tremellaceae (as previously circumscribed) is

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

(hence artificial) with most genera belonging in different families. As a result, the Tremellaceae is now restricted to the genus ''Tremella'' which is itself restricted to those species closely related to the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

Tremella mesenterica ''Tremella mesenterica'' (common names include yellow brain, golden jelly fungus, yellow trembler, and witches' butter) is a common jelly fungus in the family Tremellaceae of the Agaricomycotina. The gelatinous, orange-yellow fruit body of th ...

''.

References

{{Authority control Tremellomycetes Basidiomycota families Monogeneric fungus families