Biology: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, button-shaped, cup-shaped, or effused. Several species, including the type species Exidia glandulosa, have sterile pegs or pimples on their spore-bearing surface. The genus has a cosmopolitan distribution and over 25 species are currently recognized worldwide.
Taxonomy
Exidia species were originally placed in the genus Tremella along with many other gelatinous fungi. The genus Exidia was separated from Tremella by Fries in 1822, based mainly on fruit body shape. Fries initially included species now assigned to Auricularia within the genus.
Tremellochaete was originally created in 1964 by Estonian mycologist Ain Raitviir to accommodate Tremellochaete japonica, a species with a notably spiny hymenium that appeared morphologically intermediate between Exidia and Heterochaete. The genus was initially thought to be distinct as a result of molecular research, based on cladistic analysis of DNA sequences.[1][2] But subsequent research has reduced it to synonymy with Exidia.[3]
Molecular research has indicated that Exidia as formerly circumscribed was an artificial grouping.[3][4] Accordingly, some species previously placed in Exidia have now been transferred to the genera Descidia and Ulocolla, leaving Exidia sensu stricto as a natural grouping.[3] A number of species have, however, yet to be sequenced.
Description
Exidia fruit bodies are gelatinous, most non-effused species having a distinct spore-bearing upper surface and a sterile undersurface. These surfaces are either smooth or (in some species) covered in dense or scattered sterile pegs or pimples. Fruit bodies grow either separately or in groups, in which case they may coalesce.
Microscopic characters
Exidia fruit bodies are composed of hyphae with clamp connections in a gelatinous matrix. The spore-bearing surface is initially covered in a layer of branched hyphidia below which the basidia are formed. The basidia are tremelloid (ellipsoid and vertically septate), giving rise to long, sinuous sterigmata or epibasidia on which the basidiospores are produced. These spores are allantoid (sausage-shaped) or less commonly oblong to cylindrical.
Species
The list below comprises species of Exidia (including those now referred to Descidia and Ulocolla) that have recently been described or redescribed. Species marked with an asterisk have been sequenced and belong to Exidia sensu stricto.[3] 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.
| Image | Name | Type Locality |
|---|---|---|
| Exidia aeruginosa | Jamaica | |
| Exidia alveolata | Ecuador | |
| Exidia ambipapillata | Guatemala | |
| Exidia antiguae | Guatemala | |
| Exidia brunneola | Finland | |
| 150px | Exidia candida* | USA |
| Exidia ciliata* | Brazil | |
| Exidia compacta | USA | |
| 150px | Exidia crenata* | USA |
| Exidia cystidiata | USA | |
| Exidia delita* | France | |
| Exidia friesiana* | Finland | |
| 150px | Exidia glandulosa* | France |
| Exidia impressa* | France | |
| Exidia inornata* | France | |
| Exidia japonica* | Japan | |
| Exidia lutea | Guatemala | |
| Exidia maracensis | Brazil | |
| Exidia maya | Guatemala | |
| Exidia mexicana | Mexico | |
| Exidia nothofagi | New Zealand | |
| Exidia panamensis | Panama | |
| Exidia pergamena | Brazil | |
| 150px | Exidia pithya* | Germany |
| Exidia plumbescens* | USA | |
| Exidia purpureocinerea | South Africa | |
| Exidia pusilla | Brunei | |
| 150px | Exidia recisa* | Germany |
| Exidia reflexa | China | |
| 150px | Descidia repanda | Sweden |
| 150px | Ulocolla saccharina | Sweden |
| Exidia repleta* | France | |
| Exidia saturata* | France | |
| Exidia semiorbis* | Russia | |
| Exidia spiculata* | USA | |
| Exidia straminea* | France | |
| Exidia subglandulosa* | China | |
| Exidia tanzanica | Tanzania | |
| 150px | Descidia thuretiana | France |
| Exidia truncata* | Sweden | |
| Exidia tucumanensis | Argentina | |
| Exidia umbrinella* | Italy | |
| 150px | Exidia uvapassa | Japan |
| Exidia yadongensis* | China | |
| Exidia zelleri* | USA |
References
- ↑ "Taxonomy and phylogeny of the Auriculariales (Agaricomycetes, Basidiomycota) with stereoid basidiocarps". Fungal Biology 121 (8): 689–715. 2017. doi:10.1016/j.funbio.2017.05.001. PMID 28705397. Bibcode: 2017FunB..121..689M.
- ↑ "Two new genera and six other novelties in Heterochaete sensu lato (Auriculariales, Basidiomycota)". Botany 97 (8): 439–451. 2019. doi:10.1139/cjb-2019-0046.
- ↑ 3.0 3.1 3.2 3.3 "Exidia and Exidiopsis (Auriculariales, Basidiomycota): a reconsideration". IMA Fungus 17. 2026. doi:10.3897/imafungus.17.189042.
- ↑ Weiß, Michael; Oberwinkler, Franz (2001). "Phylogenetic relationships in Auriculariales and related groups – hypotheses derived from nuclear ribosomal DNA sequences". Mycological Research 105 (4): 403–415. doi:10.1017/s095375620100363x.
Wikidata ☰ Q387146 entry
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