''Exidia glandulosa'' is a species of
fungus
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
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 ...
. In the UK, it has the recommended English name of witch's butter.
In North America it has variously been called black witches' butter, black jelly roll,
or warty jelly fungus.
The gelatinous
basidiocarp
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) are up to wide, shiny, black and blister-like, and grow singly or in clusters.
It is a common
wood-rotting species in Europe, typically growing on dead attached branches of
oak
An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...
.
Taxonomy
The species was originally described from France as ''Tremella glandulosa'' by
Bulliard in 1789.
[ It was subsequently placed in '' Exidia'' by ]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 ...
in 1822.[ Fries, however, modified Bulliard's ]species concept
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 classification and ...
to include a second, effused, coalescing species—the name ''Exidia glandulosa'' serving for both. This combined concept was used until Neuhoff separated the two species in 1936. Unfortunately, Neuhoff gave the name ''Exidia glandulosa'' to the effused species, adopting the name ''Exidia truncata'' for Bulliard's original species. This error was pointed out by Donk in 1966, who proposed the name ''Exidia plana'' for the effused species,[ now replaced by '']Exidia nigricans
''Exidia nigricans'' is a species of fungus in the family Auriculariaceae. In the UK, it has the recommended English name of warlock's butter. It produces black, gelatinous basidiocarps (fruit bodies) and is a common, wood-rotting species through ...
''.[
Molecular research has shown that ''Exidia glandulosa'' and ''E. nigricans'', though similar, are distinct.][
]
Description
''Exidia glandulosa'' forms dark sepia to blackish, rubbery-gelatinous fruit bodies that are top-shaped (like an inverted cone) and around across (sometimes fusing into masses some 20 cm in length). They are firm when fresh, but become lax and distorted with age or in wet weather. The fruit bodies occur singly or in small clusters. The upper, spore-bearing surface is shiny and dotted with small pimples or pegs. The undersurface is smooth and matt at first, but develops a dense covering of small, gelatinous spines. The fruit bodies are attached to the wood at the base. The spore print
300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing warm orange ("tussock") color spore print. ...
is white.[ When the fruit bodies are dried they can shrink to form a flattened black crust.]
Microscopic characters
The microscopic characters are typical of the genus '' Exidia''. 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 ellipsoid, septate, 15–25 by 8–13 μm
The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...
. The spores
In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...
are allantoid (sausage-shaped), with dimensions of 14–19 by 4.5–5.5 μm.[
]
Similar species
''Exidia glandulosa'' is frequently confused with ''Exidia nigricans''. The two are similar, but ''E. nigricans'' produces button-shaped fruit bodies in clusters that quickly become deformed and coalesce, forming an effused, lobed mass that can be or more across. The two species are indistinguishable microscopically, but DNA research indicates they are distinct.[
The ]ascomycete
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 ...
'' Bulgaria inquinans'' forms similar, rubbery-gelatinous, blackish fruit bodies on oak. Their upper surfaces are entirely smooth, however, and they produce copious black (not white) spore prints, often leaving a black stain if wiped with the hand.[
]
Habitat and distribution
''Exidia glandulosa'' is a wood-rotting species, typically found on dead attached branches of broadleaf trees, especially oak, occasionally hazel
Hazels are plants of the genus ''Corylus'' of deciduous trees and large shrubs native to the temperate Northern Hemisphere. The genus is usually placed in the birch family, Betulaceae,Germplasmgobills Information Network''Corylus''Rushforth, K ...
or beech
Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...
. It is a pioneer species
Pioneer species are resilient species that are the first to colonize barren environments, or to repopulate disrupted biodiverse steady-state ecosystems as part of ecological succession. Various kinds of events can create good conditions for pi ...
capable of colonizing living or recently dead wood. A study of the wood decay process in attached oak branches showed that ''E. glandulosa'' is a member of a community of eight basidiomycetous
Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basid ...
fungi consistently associated with the decay of dying branches on living trees. Specifically, its role is to disintegrate the tissue of the vascular cambium
The vascular cambium is the main growth tissue in the stems and roots of many plants exhibiting secondary growth, specifically in dicots such as buttercups and oak trees, gymnosperms such as pine trees, as well as in certain other vascular ...
, which loosens the attached bark
Bark may refer to:
Common meanings
* Bark (botany), an outer layer of a woody plant such as a tree or stick
* Bark (sound), a vocalization of some animals (which is commonly the dog)
Arts and entertainment
* ''Bark'' (Jefferson Airplane album), ...
.[ It persists for some while on fallen branches and logs. The fruit bodies are normally produced in the autumn and winter.
Its global distribution outside of Europe is uncertain because of confusion with ''E. nigricans''.
]
Edibility
While nonpoisonous, one field guide says ''E. glandulosa'' is inedible, though it has also been reported to be edible.
References
External links
MushroomObserver
Images
{{DEFAULTSORT:Exidia glandulosa
Auriculariales
Fungi of Europe
Fungus species
Taxa named by Jean Baptiste François Pierre Bulliard
Fungi described in 1789