Exidia thuretiana
Encyclopedia
Exidia thuretiana is a jelly fungus in the family Auriculariaceae
. The fruit bodies
are white and gelatinous with brain-like folds. It is a common, wood-rotting
species in Europe, typically growing on dead attached or fallen branches of broadleaf trees, especially beech
.
in France and was described in 1848 by Joseph-Henri Léveillé
as Tremella thuretiana. It was subsequently transferred to the genus Exidia
by Fries
in 1874.
Donk preferred the name Exidia albida (Huds.
) Bref.
for this species, but most later authors have followed Reid
in considering E. albida a nomen dubium
(name of uncertain application) that might originally have referred to any whitish or transparent jelly fungus.
The epithet "thuretiana" compliments botanist Gustave Thuret, owner of the Château de Rentilly, in the grounds of which E. thuretiana was first collected. The recommended English name is "white brain".
or pinkish tints. The upper, spore-bearing surface (hymenium
) is smooth and opaque, but is frequently furrowed and folded. It can have a pruinose (powder-like) coating. With age, the hymenium becomes a thin, horny, yellowish film. The spore print
is white. The fungus does not have any distinct taste or odor; it is inedible.
. The basidia are ellipsoid, longitudinally septate
, and measure 14–20 x 8.5–12 µm
. The spores are allantoid (sausage-shaped), with dimensions of 13–18 x 5.5–7 µm. hypha
e have a diameter ranging from 1 to 2.5 µm.
are similarly coloured, but are typically pustular or lobed (never appearing pleated) and usually contain conspicuous, white, granular inclusions. Microscopically Myxarium nucleatum can be distinguished by its stalked basidia.
, hazel
, ash, and apple
. Exidia thuretiana typically fruits in autumn and winter. It is widely distributed in Europe, North Africa, and northern Asia. It has been collected from Greenland
.
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...
. The fruit bodies
Sporocarp (fungi)
In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...
are white and gelatinous with brain-like folds. It is a common, wood-rotting
Wood-decay fungus
A wood-decay fungus is a variety of fungus that digests moist wood, causing it to rot. Some wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria , are parasitic and colonize living trees. Fungi that not only grow on wood but actually cause it to decay, are called...
species in Europe, typically growing on dead attached or fallen branches of broadleaf trees, especially beech
Beech
Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
.
Taxonomy
The species was originally found growing on beechBeech
Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
in France and was described in 1848 by Joseph-Henri Léveillé
Joseph-Henri Léveillé
Joseph-Henri Léveillé was a French physician and mycologist who was a native of Crux-la-Ville, in the department of Nièvre....
as Tremella thuretiana. It was subsequently transferred to the genus 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...
by Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
in 1874.
Donk preferred the name Exidia albida (Huds.
William Hudson (botanist)
William Hudson FRS was a British botanist and apothecary based in London. His main work was Flora Anglica, published in 1762. He was elected a fellow of the Royal Society in 1761.- Life and work :...
) Bref.
Julius Oscar Brefeld
Julius Oscar Brefeld , usually just Oscar Brefeld, was a German botanist and mycologist.-Biography:Brefeld was a native of Telgte. He studied pharmacy in Heidelberg and Berlin, and afterwards became an assistant to Anton de Bary at the University of Halle...
for this species, but most later authors have followed Reid
Derek Reid
Derek Agutter Reid was an English mycologist.-Background and education:Reid was born in Leighton Buzzard, Bedfordshire, the son of a picture-framer. He was educated at Cedars School and the University of Hull, where he studied geology and botany...
in considering E. albida a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
(name of uncertain application) that might originally have referred to any whitish or transparent jelly fungus.
The epithet "thuretiana" compliments botanist Gustave Thuret, owner of the Château de Rentilly, in the grounds of which E. thuretiana was first collected. The recommended English name is "white brain".
Description
Exidia thuretiana forms shallowly pulvinate (cushion-shaped), gelatinous fruit bodies that individually measure 0.2 to 1 cm (0.078740157480315 to 0.393700787401575 in) in diameter. The fruit bodies quickly coalesce, often running along the underside of branches and extending up to 10 cm (4 in) or more. They typically appear undulating or pleated and are whitish, occasionally with ochreOchre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...
or pinkish tints. The upper, spore-bearing surface (hymenium
Hymenium
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...
) is smooth and opaque, but is frequently furrowed and folded. It can have a pruinose (powder-like) coating. With age, the hymenium becomes a thin, horny, yellowish film. The spore print
Spore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...
is white. The fungus does not have any distinct taste or odor; it is inedible.
Microscopic characters
The microscopic characters are typical of the genus ExidiaExidia
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...
. The basidia are ellipsoid, longitudinally septate
Septum
In anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.-In human anatomy:...
, and measure 14–20 x 8.5–12 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
. The spores are allantoid (sausage-shaped), with dimensions of 13–18 x 5.5–7 µm. hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e have a diameter ranging from 1 to 2.5 µm.
Similar species
Fruit bodies of Myxarium nucleatumMyxarium nucleatum
Myxarium nucleatum is a jelly fungus in the family Hyaloriaceae. The sporocarps are watery white and gelatinous with small, white, mineral inclusions...
are similarly coloured, but are typically pustular or lobed (never appearing pleated) and usually contain conspicuous, white, granular inclusions. Microscopically Myxarium nucleatum can be distinguished by its stalked basidia.
Habitat and distribution
Exidia thuretiana is a wood-rotting species, typically found on dead attached or fallen branches. It was originally recorded on beech and frequently occurs on this substrate, but is also known from other broadleaf trees and shrubs, including oakOak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, hazel
Hazel
The hazels are a genus of deciduous trees and large shrubs native to the temperate northern hemisphere. The genus is usually placed in the birch family Betulaceae, though some botanists split the hazels into a separate family Corylaceae.They have simple, rounded leaves with double-serrate margins...
, ash, and apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
. Exidia thuretiana typically fruits in autumn and winter. It is widely distributed in Europe, North Africa, and northern Asia. It has been collected from Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
.