''Exidia recisa'' (

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

willow brain or amber jelly roll) is a

jelly fungus Jelly fungi are a paraphyletic group of several heterobasidiomycete fungal orders from different classes of the subphylum Agaricomycotina: Tremellales, Dacrymycetales, Auriculariales and Sebacinales. These fungi are so named because their foli ...

in the family

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 (fruit bodies) that produce spores on ...

. It is a common, wood-rotting species throughout the northern hemisphere, typically growing on dead attached twigs and branches of

willow Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...

and other broadleaf trees.

Taxonomy

The species was originally found growing on willow in Germany and was described in 1813 by L.P.F. Ditmar as ''Tremella recisa''. It was transferred to the genus ''

Exidia ''Exidia'' is a genus of fungi in the family Auriculariaceae. The species are saprotrophic, occurring in attached or recently fallen dead wood, and produce gelatinous basidiocarps (fruit bodies). The fruit bodies are diverse, pustular, lobed, but ...

'' by

Fries French fries (North American English), chips (British English), finger chips (Indian English), french-fried potatoes, or simply fries, are '' batonnet'' or ''allumette''-cut deep-fried potatoes of disputed origin from Belgium and France. The ...

in 1822. ''Tremella salicum'' (the

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

means "of willow") has long been considered a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

. The epithet "recisa" means "cut-off", with reference to the shape of the fruit bodies.

Description

''Exidia recisa'' forms orange-brown or amber, gelatinous fruit bodies that are firm and shallowly conical at first, becoming lax and pendulous with age, and around 2.5 cm (1 in) across. The fruit bodies typically grow gregariously, but do not normally coalesce. The upper, spore-bearing surface is smooth and shiny, whilst the undersurface is smooth and matt. Fruit bodies are attached to the wood at a point, but do not have a

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

. 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 pinkish-tan spore print. A 3.5-centimeter ...

is white.

Microscopic characters

The microscopic characters are typical of the genus ''

''. The

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

are ellipsoid, septate, 8–15 x 6–10 μm. The

spores In biology, a spore is a unit of sexual 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 plants, algae, f ...

are allantoid (sausage-shaped), 14–15 x 3–3.5 μm.

Similar species

Fruit bodies of ''

Exidia repanda ''Exidia'' is a genus of fungi in the family Auriculariaceae. The species are saprotrophic, occurring in attached or recently fallen dead wood, and produce gelatinous basidiocarps (fruit bodies). The fruit bodies are diverse, pustular, lobed, bu ...

'' are similarly coloured and microscopically indistinguishable. The fruit bodies are button-shaped, however, never becoming conical and pendulous, and the species typically occurs on

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

, never on willow. Fruit bodies of '' Exidia umbrinella'' are also similar, but the species only occurs on conifers and is uncommon. The widespread ''

Exidia glandulosa ''Exidia glandulosa'' (common names black witches' butter, black jelly roll, or warty jelly fungus) is a jelly fungus in the family Auriculariaceae. It is a common, wood-rotting species in Europe, typically growing on dead attached branches of ...

'' has much darker, blackish brown fruit bodies with sparse warts or small, peg-like projections on their surface.

Habitat and distribution

''Exidia recisa'' is a wood-rotting species, typically found on dead attached twigs and branches. It was originally recorded on willow and most frequently occurs on this substrate, although it has also been reported on poplar,

alder Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...

, and ''

Prunus ''Prunus'' is a genus of trees and shrubs, which includes (among many others) the fruits plums, cherries, peaches, nectarines, apricots, and almonds. Native to the North American temperate regions, the neotropics of South America, and the p ...

'' species. ''Exidia recisa'' typically fruits in autumn and winter. It is widely distributed in North and Central America, Europe, and northern Asia.

References

{{DEFAULTSORT:Exidia recisa Auriculariales Fungi described in 1813 Fungi of Asia Fungi of Europe Fungi of North America Fungi of South America