The Auriculariales are an
order of
fungi
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
class
Class, Classes, or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used d ...
Agaricomycetes
The Agaricomycetes are a class of fungi in the division Basidiomycota. The taxon is roughly identical to that defined for the Homobasidiomycetes (alternatively called holobasidiomycetes) by Hibbett & Thorn, with the inclusion of Auriculariales ...
. Species within the order were formerly referred to the "
heterobasidiomycetes" or "jelly fungi", since many have gelatinous
basidiocarps (fruit bodies) that produce spores on septate
basidia. Around 200 species are known worldwide, placed in six or more
families, though the status of these families is currently uncertain. All species in the Auriculariales are believed to be
saprotrophic, most growing on dead wood. Fruit bodies of several ''
Auricularia'' species are cultivated for food on a commercial scale, especially in China.
Taxonomy
History
The order was established in 1889 by German
mycologist Joseph Schröter to accommodate species of fungi having "auricularioid"
basidia (more or less cylindrical basidia with lateral septa), including many of the
rusts and
smuts. In 1922, British mycologist
Carleton Rea recognized the order as containing the families
Auriculariaceae and Ecchynaceae, as well as the rusts (
Coleosporiaceae and
Pucciniaceae) and the smuts (
Ustilaginaceae).
Many subsequent authors, however, separated out the rusts and smuts and amalgamated the remaining Auriculariales with the
Tremellales.
Jülich (1981) also separated out the rusts and smuts, but recognized the remaining Auriculariales as an independent order, placing within them the families Auriculariaceae,
Cystobasidiaceae, Paraphelariaceae, Saccoblastiaceae, Ecchynaceae,
Hoehnelomycetaceae, and
Patouillardinaceae.
A radical revision was undertaken in 1984, when American mycologist
Robert Joseph Bandoni used
transmission electron microscopy
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a g ...
to investigate the
ultrastructure of the septal pore apparatus in the Auriculariales. This revealed that species of fungi with "auricularioid" basidia were not necessarily closely related and that ''
Auricularia'' had more in common with ''
Exidia'' and its allies (with "tremelloid" basidia), than with other auricularioid fungi. Bandoni therefore amended the Auriculariales to include the family
Auriculariaceae (with auricularioid basidia) together with the families Exidiaceae, Aporpiaceae,
Hyaloriaceae, and
Sebacinaceae (with tremelloid basidia).
This revision was accepted by Wells (1994) who, however, amalgamated the Aporpiaceae and Hyaloriaceae (together with the
Heteroscyphaceae) and added the families
Patouillardinaceae (with diagonally septate basidia) and
Tremellodendropsidaceae (with partly septate basidia).
Roberts (1998) subsequently added the family
Oliveoniaceae (with non-septate basidia).
Current status
Molecular research, based on
cladistic
Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...
analysis of
DNA sequences
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the ...
, has substantially supported Bandoni's revised circumscription of the Auriculariales, but has moved the Sebacinaceae and the Tremellodendropsidaceae to their own separate orders, the
Sebacinales and
Tremellodendropsidales.
[ The status of the constituent families has not yet been examined, but a clade containing ''Auricularia'' and ''Exidia'' species equates to the Auriculariaceae, whilst another containing '' Hyaloria'' and '' Myxarium'' species equates to the Hyaloriaceae.]
Description
The majority of species within the Auriculariales produce gelatinous basidiocarps (fruit bodies) on dead wood. In some these are conspicuous and may be ear-shaped, button-shaped, lobed, bracket-like, or effused. Their hymenophores (spore-bearing surfaces) may be smooth, warted, veined, toothed (as in the genus '' Pseudohydnum''), cyphelloid (as in the genus '' Heteroscypha''), or poroid (as in the genera '' Elmerina'' and '' Aporpium''). Some species, however, produce dry, leathery, or web-like fruit bodies resembling those of the corticioid fungi.
Distribution and habitat
All species within the Auriculariales are thought to be saprotrophs, most of them wood-rotters. They are typically found on dead attached or fallen wood, though a few ('' Guepinia'' species) are normally found on the ground. As a group, their distribution is cosmopolitan.
Economic importance
Several species within the order are edible and two, '' Auricularia heimuer'' and '' Auricularia cornea'', are cultivated on a commercial scale, particularly in China and southeast Asia.
File:Auricularia cornea 32082.jpg,
File:Exidia glandulosa.jpg,
File:Exidia recisa 34873 cropped.jpg,
File:Guepinia helvelloides 47030.jpg,
File:Myxarium nucleatum 108643403.jpg,
File:Pseudohydnum.gelatinosum2.-.lindsey.jpg,
References
{{Authority control
Basidiomycota orders
Taxa named by Joseph Schröter
Taxa described in 1889