''Phaeotremella'' 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 ...

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

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 ...

Phaeotremellaceae The Phaeotremellaceae are a family of fungi in the order Tremellales. The family currently contains two genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fo ...

. All ''Phaeotremella'' species 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 and produce

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 ...

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

states.

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 and are colloquially classed among the " jelly fungi". Fifteen or so species of ''Phaeotremella'' are currently recognized worldwide. '' Tremella sanguinea'', shown to be a ''Phaeotremella'' species by DNA sequencing, is cultivated in China as an ingredient in traditional Chinese medicine.

Taxonomy

History

The genus ''Phaeotremella'' was originally created by British mycologist

Carleton Rea Carleton Rea (7 May 1861 – 26 June 1946) was an English mycologist, botanist, and naturalist. Background and education Carleton Rea was born in Worcester, the son of the City Coroner. He was educated at The King's School and Magdalen Coll ...

to accommodate ''Phaeotremella pseudofoliacea'', a fungus that resembled a '' Tremella'' species but had brown rather than white

basidiospores A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are pr ...

. Later authors considered this to be a mistaken observation and placed ''Phaeotremella'' in synonymy with ''Tremella'' and its type species in synonymy with ''Tremella foliacea''.

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 ...

, has however shown that ''Tremella'' is

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

(and hence artificial). A different generic name was therefore required for a group of species not closely related to ''

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 ...

'' (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 ...

of ''Tremella'') and ''Phaeotremella'' was selected as the earliest such name available. As a result, the current definition of ''Phaeotremella'' is not the same as Rea's original concept. The type species, ''P. pseudofoliacea'', has been placed in synonymy with '' Phaeotremella frondosa''.

Description

Fruit bodies (when present) are gelatinous. In some species they are small (under 5 mm across) and pustular to pulvinate (cushion-shaped). In others they are much larger (up to 150 mm across) and may be variously lobed or foliose (with leaf-like or seaweed-like fronds). Several ''Phaeotremella'' species are, however, only known from their yeast states.

Microscopic characters

''Phaeotremella'' species produce

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 o ...

that are typically (but not always) clamped and have haustorial cells from which hyphal filaments seek out and penetrate the hyphae of the host. 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 ...

are "tremelloid" (globose to ellipsoid and vertically or diagonally septate), giving rise to long, sinuous

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 ...

or epibasidia on which the

are produced. These spores are smooth, globose to ellipsoid, and germinate by hyphal tube or by

cells.

Conidiophores A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

are often present, producing conidiospores that are similar to yeast cells.

Habitat and distribution

Most species are parasitic on members of the corticioid fungi, specifically species of '' Aleurodiscus'' and '' Stereum'', with one species on the ascomycetous genus '' Lophodermium''. Those on ''Aleurodiscus'', including ''Phaeotremella mycophaga'', parasitize the fruit bodies of their hosts; those on ''Stereum'', such as '' Phaeotremella foliacea'', ''P. frondosa'', and ''P. fimbriata'', parasitize the host

mycelium Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are fo ...

within the wood. As a group, ''Phaeotremella'' species occur worldwide, though individual species may have a more restricted distribution.

Species and hosts

Only species producing basidiocarps (fruit bodies) are listed. Not all hosts are known.

References

{{Taxonbar, from=Q27863235 Tremellomycetes Basidiomycota genera Taxa described in 1912 Yeasts