Tremellaceae
Encyclopedia
The Tremellaceae are a family
of fungi in the order
Tremellales
. The family is cosmopolitan
and contains both teleomorphic and anamorphic genera
, most of the latter being yeasts. All teleomorphic species
of fungi in the Tremellaceae are parasites
of other fungi, though the yeast states are widespread and not restricted to hosts. Basidiocarps (fruit bodies), when produced, are gelatinous.
The family currently comprises 18 genera (plus synonyms), containing around 250 valid species. Significant genera include Tremella
, two species of which are edible
and commercially cultivated, and the yeast genus Cryptococcus
, several species of which are human pathogens, causing cryptococcosis
.
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
, Dacrymyces
, Exidia
, Hymenella, Naematelia, and Tremella
. Agyrium and Hymenella are now referred to the Ascomycota
, 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 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
, Sirobasidium, Tremella, and Tremellodon (= Pseudohydnum
).
The next major revision was in 1984, when Bandoni used transmission electron microscopy
to investigate the ultrastructure
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
, restricting the Tremellaceae to the genera Holtermannia, Tremella, and Trimorphomyces
. The genus Sirobasidium and its allies were placed in the Sirobasidiaceae
.
(and its yeast state Cryptococcus) should be included within the group, even though its basidia are not tremelloid. The research does not, however, support a distinct family Tremellaceae within the order Tremellales, but instead divides the order (and indeed the genus Tremella) into several small clades. As currently circumscribed, the Tremellaceae is therefore an artificial subset of the Tremellales, not clearly distinct from the Sirobasidiaceae.
of their hosts and do not produce visible fruit bodies. When fruit bodies are produced, they are always gelatinous, and typically brightly coloured. Microscopically, all have hyphae bearing haustorial cells which produce filaments that connect to the hyphae of their host fungi. Except in the genus Filobasidiella
, the basidia are "tremelloid": globose to ellipsoid with vertical or diagonal septa, producing basidiospores on long, indeterminate sterigmata or epibasidia. Basidiospores in most (but not all) species germinate by producing germ tube
s (normal for basidiomycetes) or yeast cells. Many species of the Tremellaceae also produce asexual conidiospores.
Ascomycota
(including lichens) and Basidiomycota
. They typically parasitize species that grow on dead wood of living shrubs and trees and it may be that their gelatinous fruit bodies are an adaption to such a periodically arid environment. The family is cosmopolitan
in distribution, though individual species may be restricted to temperate regions or the tropics. The anamorphic yeast states are typically widespread and not restricted to host or substrate.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of fungi in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Tremellales
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 yeast states are widespread and not restricted to...
. The family is cosmopolitan
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
and contains both teleomorphic and anamorphic genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
, most of the latter being yeasts. All teleomorphic species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of fungi in the Tremellaceae are parasites
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
of other fungi, though the yeast states are widespread and not restricted to hosts. Basidiocarps (fruit bodies), when produced, are gelatinous.
The family currently comprises 18 genera (plus synonyms), containing around 250 valid species. Significant genera include Tremella
Tremella
Tremella is a genus of fungi in the family Tremellaceae. All Tremella species are parasites of other fungi and most produce anamorphic yeast states. Basidiocarps , when produced, are gelatinous and are colloquially classed among the "jelly fungi". Over 100 species of Tremella are currently...
, two species of which are edible
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
and commercially cultivated, and the yeast genus Cryptococcus
Cryptococcus
Cryptococcus is a genus of fungus. Species grow in culture as yeasts. The perfect forms or teleomorphs of Cryptococcus species are filamentous fungi in the genus Filobasidiella...
, several species of which are human pathogens, causing cryptococcosis
Cryptococcosis
Cryptococcosis, or cryptococcal disease, is a potentially fatal fungal disease. It is caused by one of two species; Cryptococcus neoformans and Cryptococcus gattii. These were all previously thought to be subspecies of C...
.
History
FriesElias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
created the family Tremellaceae (as 'Tremellini') in 1821, basing it on the macromorphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
of fruit bodies. He included within it most species of fungi that were gelatinous, dividing it into the genera Agyrium
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....
, Dacrymyces
Dacrymyces
Dacrymyces is a genus of fungi in the Dacrymycetales order. The genus contains about 39 widely distributed species.-Species:*Dacrymyces ancyleus*Dacrymyces aureosporus*Dacrymyces australis*Dacrymyces capitatus...
, Exidia
Exidia
Exidia is a genus of fungi in the family Auriculariaceae. Species are saprotrophic, growing on dead attached or recently fallen wood, and produce gelatinous basidiocarps . The fruit bodies are variously pustular, lobed, button-shaped, or top-shaped...
, Hymenella, Naematelia, and Tremella
Tremella
Tremella is a genus of fungi in the family Tremellaceae. All Tremella species are parasites of other fungi and most produce anamorphic yeast states. Basidiocarps , when produced, are gelatinous and are colloquially classed among the "jelly fungi". Over 100 species of Tremella are currently...
. Agyrium and Hymenella are now referred to the Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
, as are several of the species Fries placed in Dacrymyces and Tremella.
In 1900 Patouillard
Narcisse Théophile Patouillard
Narcisse Théophile Patouillard was a French pharmacist and mycologist.He was born in Macornay, a town in the department of Jura...
radically revised the family by switching the emphasis to the micromorphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
of fruit bodies. For Patouillard, the Tremellaceae was limited to genera and species in which the basidia 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
Holtermannia
Holtermannia is a genus of fungi in the family Tremellaceae. The genus is distributed in southeast Asia and Brazil, and contains seven species....
), Ditangium, Exidia, Guepinia
Guepinia
Guepinia is a genus of fungus in the Auriculariales order. It is a monotypic genus, containing the single species Guepinia helvelloides, commonly known as the apricot jelly. The fungus produces salmon-pink, ear-shaped, gelatinous fruit bodies that grow solitarily or in small tufted groups on soil,...
, Heterochaete
Heterochaete
Heterochaete is a genus of fungi in the family Auriculariaceae. The genus has a widespread distribution, especially in tropical regions, and contains about 40 species....
, Hyaloria, Protomerulius
Protomerulius
Protomerulius is a genus of fungi in the order Auriculariales. The genus is estimated to contain about four species....
, Sebacina
Sebacina
Sebacina is a genus of fungi in the family Sebacinaceae. Its species are mycorrhizal, forming a range of associations with trees, orchids, and other plants. Basidiocarps are produced on soil and litter, sometimes partly encrusting stems of living plants. The fruit bodies are cartilaginous to...
, Sirobasidium, Tremella, and Tremellodon (= Pseudohydnum
Pseudohydnum
Pseudohydnum is a genus of fungi in the order Auriculariales. The genus, first described by mycologist Petter Adolf Karsten in 1868, has not been classified with certainty into a family, and so is incertae sedis with respect to familial placement. Pseudohydnum is monotypic, containing only the...
).
The next major revision was in 1984, when Bandoni used transmission electron microscopy
Transmission electron microscopy
Transmission electron microscopy is a microscopy technique whereby a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it passes through...
to investigate the ultrastructure
Ultrastructure
Ultrastructure is the detailed structure of a biological specimen, such as a cell, tissue, or organ, that can be observed by electron microscopy...
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
Auriculariaceae
The Auriculariaceae are a family of fungi in the order Auriculariales. Species within the family were formerly referred to the "heterobasidiomycetes" or "jelly fungi", since many have gelatinous basidiocarps that produce spores on septate basidia. Around 100 species are known worldwide. All are...
, restricting the Tremellaceae to the genera Holtermannia, Tremella, and Trimorphomyces
Trimorphomyces
Trimorphomyces is a genus of fungi in the family Tremellaceae. The monotypic genus has a North American distribution, and contains the single species Trimorphomyces papilionaceus....
. The genus Sirobasidium and its allies were placed in the Sirobasidiaceae
Sirobasidiaceae
The Sirobasidiaceae are a family of fungi in the order Tremellales. Taxa are widespread, primarily tropical, and typically grow on wood and bark....
.
Current status
Molecular research, based on cladistic analysis of DNA sequences, confirms Bandoni's split between the tremelloid and exidioid fungi and extends the circumscription of the tremelloid group by including several yeast genera whose status was formerly uncertain. Molecular research has also indicated that the genus FilobasidiellaFilobasidiella
Filobasidiella is a genus of fungi in the family Tremellaceae. Species are parasitic on other fungi and do not produce distinct basidiocarps . The genus is the teleomorphic state of the yeast genus Cryptococcus, some species of which are human pathogens.-History:The genus was first described in...
(and its yeast state Cryptococcus) should be included within the group, even though its basidia are not tremelloid. The research does not, however, support a distinct family Tremellaceae within the order Tremellales, but instead divides the order (and indeed the genus Tremella) into several small clades. As currently circumscribed, the Tremellaceae is therefore an artificial subset of the Tremellales, not clearly distinct from the Sirobasidiaceae.
Description of teleomorphs
Many species of the Tremellaceae occur in the hymeniumHymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
of their hosts and do not produce visible fruit bodies. When fruit bodies are produced, they are always gelatinous, and typically brightly coloured. Microscopically, all have hyphae bearing haustorial cells which produce filaments that connect to the hyphae of their host fungi. Except in the genus Filobasidiella
Filobasidiella
Filobasidiella is a genus of fungi in the family Tremellaceae. Species are parasitic on other fungi and do not produce distinct basidiocarps . The genus is the teleomorphic state of the yeast genus Cryptococcus, some species of which are human pathogens.-History:The genus was first described in...
, the basidia are "tremelloid": globose to ellipsoid with vertical or diagonal septa, producing basidiospores on long, indeterminate sterigmata or epibasidia. Basidiospores in most (but not all) species germinate by producing germ tube
Germ tube
A germ tube is an outgrowth produced by spores of spore-releasing fungi during germination.The germ tube differentiates, grows, and develops by mitosis to create somatic hyphae....
s (normal for basidiomycetes) or yeast cells. Many species of the Tremellaceae also produce asexual conidiospores.
Habitat and distribution
Teleomorphic species of the Tremellaceae are parasitic on other fungi in the phylaPhylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
(including lichens) and Basidiomycota
Basidiomycota
Basidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi...
. They typically parasitize species that grow on dead wood of living shrubs and trees and it may be that their gelatinous fruit bodies are an adaption to such a periodically arid environment. The family is cosmopolitan
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
in distribution, though individual species may be restricted to temperate regions or the tropics. The anamorphic yeast states are typically widespread and not restricted to host or substrate.