# 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 (fruit bodies), when produced, are gelatinous and are colloquially classed among the "jelly fungi". Over 100 species of Tremella (in its wide sense) are currently recognized worldwide. One species, Tremella fuciformis, is commercially cultivated for food.

## Taxonomy
### History

Tremella was one of the original genera created by Linnaeus in his Species Plantarum of 1753. The name comes from the Latin tremere meaning "to tremble". Linnaeus placed Tremella in the algae, including within it a variety of gelatinous growths, including seaweeds, cyanobacteria, and myxomycetes, as well as fungi. Subsequent authors added additional species to this mix, until Persoon revised Tremella in 1794 and 1801, repositioning the genus within the fungi.
Persoon's reinterpretation of Tremella was sufficiently radical to be considered a separate genus (Tremella Pers.) from that originally created by Linnaeus (Tremella L.). Tremella Pers. has now been conserved under the International Code of Nomenclature for algae, fungi, and plants, with Tremella mesenterica as the type species.

### Current status

Molecular research, based on cladistic analysis of DNA sequences, has shown that Tremella (as previously understood) is polyphyletic (and hence artificial), with most species not closely related to the type. Accordingly, some species have been transferred to new genera and new families: Tremella foliacea and related species are now placed in the genus Phaeotremella within the family Phaeotremellaceae; Tremella encephala and related species are now placed in the genus Naematelia within the Naemateliaceae; Tremella moriformis and related species are now placed in the genus Pseudotremella within the Bulleraceae; and Tremella polyporina is now placed in the genus Carcinomyces within the Carcinomycetaceae. Several other species groups have not yet been renamed, pending further research.
More than 500 species have been described in Tremella, but most of these are old names either of doubtful application or for species later transferred to other genera. In its strict sense the genus Tremella now contains some 30-40 species, including the type Tremella mesenterica and the cultivated species T. fuciformis.

## 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, cephaliform (like a brain, with folds and ridges), or foliose (with leaf-like or seaweed-like fronds). Many Tremella species, however, are hymenial parasites, producing spores within the fruit bodies of their hosts, and are only visible microscopically.

### Microscopic characters

Tremella species produce hyphae 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 are "tremelloid" (globose to ellipsoid, sometimes stalked, and vertically or diagonally septate), giving rise to long, sinuous sterigmata or epibasidia on which the basidiospores are produced. These spores are smooth, globose to ellipsoid, and germinate by hyphal tube or by yeast cells. Conidiophores are often present, producing conidiospores that are similar to yeast cells.

## Habitat and distribution

Species are mainly parasitic on wood-rotting fungi in the phyla Ascomycota and Basidiomycota, particularly on species that occur on dead attached branches. Hosts include members of the corticioid fungi and Dacrymycetales in the Basidiomycota and species of Diaporthe, other Sordariomycetes, and lichens in the Ascomycota. Some Tremella species parasitize the fruit bodies of their hosts, others parasitize the mycelium within the wood.
As a group, Tremella species occur worldwide, though individual species may have a more restricted distribution.

## Species and hosts

The list below includes species of Tremella (in the wide sense) that have recently been described or redescribed based on fruit bodies. Species based on yeasts are not included. Some additional older species may also be valid, but lack a modern description. The type locality (but not the wider distribution) is given for each species together with the host fungus, where known. Species belonging to Tremella in the strict sense are marked as such, as are those that have been transferred to new genera.
| Name | Current Status | Type Locality | Host |
| Tremella anaptychiae | | Spain | Anaptychia ciliaris |
| Tremella anomala | | Brazil | Hypoxylon spp |
| Tremella arachispora | | Cameroon | unknown |
| Tremella armeniaca | Tremella sensu stricto | Costa Rica | Xylaria sp? |
| Tremella aurantia | Naematelia aurantia | USA | Stereum hirsutum |
| Tremella aurantialba | Naematelia aurantialba | China | Stereum hirsutum |
| Tremella aurantiolutea | | Mexico | unknown |
| Tremella australe | Tremella sensu stricto | China | unknown |
| Tremella australiensis | | Australia | Stereum spp |
| Tremella boninensis | Tremella sensu stricto | Japan | unknown |
| Tremella boraborensis | | Tahiti | unknown |
| Tremella brasiliensis | Tremella sensu stricto | Brazil | unknown |
| Tremella callunicola | | Scotland | Aleurodiscus norvegicus |
| Tremella caloceraticola | | Denmark | Calocera cornea |
| Tremella caloplacae | | Greece | Caloplaca spp(as Tremella sp. 1) |
| Tremella candelariellae | | Luxembourg | Candelariella spp |
| Tremella cephalodiicola | | Papua New Guinea | Psoroma pannarioides |
| Tremella cerebriformis | Tremella sensu stricto | Taiwan | unknown |
| Tremella cetrariicola | | Scotland | Cetraria spp |
| Tremella cheejenii | Tremella sensu stricto | China | unknown |
| Tremella christiansenii | | Denmark | Physcia spp |
| Tremella cladoniae | | Germany | Cladonia spp |
| Tremella clavisterigma | | Guatemala | unknown |
| Tremella coalescens | Tremella sensu stricto | USA | unknown |
| Tremella coccocarpiae | | Philippines | Coccocarpia rottleri |
| Tremella coffeicolor | | Bermuda | unknown(as T. auricularia) |
| Tremella colpomaticola | | Denmark | Colpoma quercinum |
| Tremella compacta | | Brazil | unknown |
| Tremella coppinsii | | Sarawak | Platismatia spp |
| Tremella dactylobasidia | | Spain | Dendrothele macrosporae |
| Tremella dendrographae | | USA | Dendrographa minor |
| Tremella diaporthicola | | USA | Diaporthe spp |
| Tremella discicola | | Belgium | Mollisia and Pyrenopeziza spp |
| Tremella dumontii | | Ecuador | unknown |
| Tremella durissima | | Argentina | unknown |
| Tremella dysenterica | Tremella sensu stricto | Brazil | unknown |
| Tremella encephala | Naematelia encephala | Europe | Stereum sanguinolentum |
| Tremella erythrina | Tremella sensu stricto | China | unknown |
| Tremella everniae | | China | Evernia mesomorpha |
| Tremella exigua | | France | Diaporthe spp |
| Tremella fibulifera | Tremella sensu stricto | Brazil | unknown |
| Tremella fimbriata | Phaeotremella fimbriata | Europe | Stereum rugosum |
| Tremella flammea | Tremella sensu stricto | Japan | |
| Tremella flava | Tremella sensu stricto | Taiwan | Hypoxylon spp |
| Tremella foliacea | Phaeotremella foliacea | Europe | Stereum sanguinolentum |
| Tremella frondosa | Phaeotremella frondosa | Europe | Stereum spp |
| Tremella fuciformis | Tremella sensu stricto | Brazil | Annulohypoxylon archeri and other Annulohypoxylon and/or Hypoxylon spp. |
| Tremella fungicola | | Denmark | Mollisia cinerea |
| Tremella fuscosuccinea | Phaeotremella fuscosuccinea | Taiwan | unknown |
| Tremella giraffa | | Germany | Dacrymyces spp |
| Tremella globispora | Tremella sensu stricto | England | Diaporthe spp |
| Tremella graphidastrae | | Papua New Guinea | Graphidastra multiformis |
| Tremella guangxiensis | Tremella sensu stricto | China | unknown |
| Tremella guttiformis | | Sri Lanka | unknown |
| Tremella haematommatis | | USA | Haematomma puniceum |
| Tremella hainanensis | Tremella sensu stricto | China | unknown |
| Tremella harrisii | | USA | Polymeridium catapastum |
| Tremella huuskonenii | | | Raesaenenia huuskonenii |
| Tremella hymenophaga | | Spain | Scytinostroma odoratum |
| Tremella hypocenomycis | | Finland | Hypocenomyce spp |
| Tremella hypogymniae | | France | Hypogymnia spp |
| Tremella iduensis | Tremella sensu stricto | Japan | Hypoxylon spp |
| Tremella imshaugiae | | USA | Imshaugia aleurites |
| Tremella indecorata | | Norway | Diatrype bullata |
| Tremella invasa | | Denmark | Trechispora spp |
| Tremella karstenii | | Finland | Colpoma juniperi |
| Tremella latispora | Tremella sensu stricto | China | unknown |
| Tremella leptogii | | Peru | Leptogium sp. |
| Tremella lethariae | | Canada | Letharia vulpina |
| Tremella lichenicola | | Luxembourg | Mycoblastus fucatus |
| Tremella lilacea | | Costa Rica | Diaporthe sp? |
| Tremella lloydiae-candidae | Tremella sensu stricto | Japan | unknown |
| Tremella lobariacearum | | Madeira | Lobariaceae spp |
| Tremella macroceratis | | Norway | Cladonia macroceras |
| Tremella mangensis | | China | unknown |
| Tremella mesenterella | Tremella sensu stricto | Canada | Peniophora spp |
| Tremella mesenterica | Tremella sensu stricto | Sweden | Peniophora spp |
| Tremella microcarpa | | Papua New Guinea | lichen sp. |
| Tremella microspora | Naematelia microspora | South Africa | Stereum spp |
| Tremella monospora | | Peru | Leptogium sp. |
| Tremella montis-wilhelmii | | Papua New Guinea | Normandina simodense sp. |
| Tremella moriformis | Pseudotremella moriformis | England | Diaporthe spp |
| Tremella mycetophiloides | Phaeotremella mycetophiloides | Japan | Aleurodiscus amorphus and A. grantii |
| Tremella mycophaga | Phaeotremella mycophaga | Canada | Aleurodiscus amorphus and A. grantii |
| Tremella nashii | | USA | Usnea sorediifera |
| Tremella nephromatis | | Canada | Nephroma parile |
| Tremella nieblae | | USA | Niebla cephalota |
| Tremella nigrifacta | | Costa Rica | Diatrypella sp. |
| Tremella nivalis | Pseudotremella nivalis | Taiwan | Diatrype spp |
| Tremella normandinae | | Hawaii | Normandina pulchella |
| Tremella obscura | | USA | Dacrymyces spp |
| Tremella occultifuroidea | | Taiwan | Dacrymyces spp |
| Tremella olens | Tremella sensu stricto | Australia | unknown |
| Tremella papuana | | Papua New Guinea | Hypogymnia pseudobitteriana |
| Tremella parmeliarum | | Papua New Guinea | Parmotrema spp |
| Tremella parmeliellae | | Papua New Guinea | Parmeliella foliicola |
| Tremella penetrans | | Denmark | Dacrymyces spp |
| Tremella pertusariae | | Northern Ireland | Pertusaria spp |
| Tremella phaeographidis | | England | Phaeographis spp |
| Tremella phaeographinae | | USA | Phaeographina spp |
| Tremella phaeophysciae | | Denmark | Phaeophyscia orbicularis |
| Tremella philippinensis | Tremella sensu stricto | Philippines | unknown |
| Tremella poilkavensis | | India | Biscogniauxia sp. |
| Tremella polyporina | Carcinomyces polyporinus | Scotland | Postia spp |
| Tremella protoparmeliae | | England | Protoparmelia spp |
| Tremella pseudocyphellariae | | Mauritius | Pseudocyphellaria desfontainii |
| Tremella psoroglaenae | | Papua New Guinea | Psoroglaena spp |
| Tremella psoromicola | | Chile | Psoroma spp |
| Tremella puncteliae | | Mexico | Punctelia borreri |
| Tremella puncteliotegens | | New Zealand | Punctelia borreri |
| Tremella purpurascentis | | USA | Dirinaria purpurascens |
| Tremella pyrenaica | | France | Lecanora polytropa |
| Tremella ramalinae | | Mexico | Ramalina spp |
| Tremella ramboidiae | | USA | Ramboldia haematites |
| Tremella resupinata | Tremella sensu stricto | Taiwan | Hypoxylon spp |
| Tremella rhabdodisci | | Japan | Rhabdodiscus inalbescens |
| Tremella rhizocarpicola | | Norway | |
| Tremella rinodinae | | Denmark | Rinodina spp |
| Tremella robusta | | USA | Roccellina fransciscana |
| Tremella rosea | | Austria | unknown |
| Tremella roseolutescens | Tremella sensu stricto | Costa Rica | unknown |
| Tremella rubromaculata | Tremella sensu stricto | Guatemala | unknown |
| Tremella salmonea | Tremella sensu stricto | China | unknown |
| Tremella samoensis | Tremella sensu stricto | Samoa | unknown |
| Tremella sanguinea | Phaeotremella | China | Stereum sp. |
| Tremella santessonii | | Zimbabwe | Usnea spp |
| Tremella sarcographae | | Brazil | Sarcographa medusulina |
| Tremella sarniensis | | Guernsey | Phanerochaete sordida |
| Tremella seclusa | | France | unknown |
| Tremella silvae-dravedae | | Denmark | unknown |
| Tremella simplex | Phaeotremella simplex | Canada | Aleurodiscus amorphus |
| Tremella spicifera | | Belgium | Massarina arundinacea |
| Tremella steidleri | | Czech Republic | Stereum hirsutum |
| Tremella stevensiana | | Australia | Usnea confusa |
| Tremella stictae | | Rwanda | Sticta weigelii |
| Tremella strigulae | | USA | Strigula stigmatella |
| Tremella subalpina | | Russia | unknown |
| Tremella subencephala | | Canada | Acanthophysium lividocoeruleum |
| Tremella subfibulifera | Tremella sensu stricto | Brazil | unknown |
| Tremella subrubiginosa | Tremella sensu stricto | Panama | unknown |
| Tremella sulcariae | | China | Sulcaria sulcata |
| Tremella synarthoniae | | USA | Synarthonia inconspicua |
| Tremella taiwanensis | Tremella sensu stricto | Taiwan | unknown |
| Tremella tawa | Tremella sensu stricto | New Zealand | unknown |
| Tremella telleriae | | Spain | Postia spp |
| Tremella teloschistis | | USA | Teloschistes exilis |
| Tremella tornabeae | | Canary Islands | Tornabea scutellifera |
| Tremella translucens | Phaeotremella translucens | Scotland | Lophodermium spp(as Sirotrema translucens) |
| Tremella tremelloides | Naematelia | USA | Stereum sp. |
| Tremella tropica | Tremella sensu stricto | Taiwan | unknown |
| Tremella tubulosae | | Scotland | Hypogymnia tubulosa |
| Tremella tuckerae | | USA | Ramalina sinensis |
| Tremella umbilicariae | | Peru | Umbilicaria sp. |
| Tremella versicolor | | England | Peniophora spp |
| Tremella vesiculosa | | New Zealand | Xylaria sp? |
| Tremella volcanagua | | Guatemala | unknown |
| Tremella wedinii | | USA | |
| Tremella wirthii | | Germany | Protoparmelia sp. |
| Tremella wrightii | | Cuba | unknown |
| Tremella xanthomendozae | | USA | Gallowayella weberi |
| Tremella yokohamensis | Tremella sensu stricto | Japan | unknown |
| Tremella zamorae | | USA | Lecanora louisianae |
| Tremella zhejiangensis | Tremella sensu stricto | China | unknown |