Megalocystidium

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Megalocystidium
Systematics
Subdivision : Agaricomycotina
Class : Agaricomycetes
Subclass : insecure position (incertae sedis)
Order : Russulales (Russulales)
Family : Layer mushroom relatives (Stereaceae)
Genre : Megalocystidium
Scientific name
Megalocystidium
Jülich

Megalocystidium is a genus of funguswithin the family of the layer fungus relatives (Stereaceae). The genus is one of the first to beseparatedfrom the Gloeocystidiellum complex. The white rot fungus has resupinate , membranous to waxy fruiting bodies that cover the substrate like crusts. The narrow-clumped basidia are usually somewhat longer and the usually smooth, amyloid basidiospores somewhat larger than in other species of the Gloeocystidiellum complex. Its hyphae usually have buckles and the gloeocystids are (even if often only weakly) sulfoaldehyde-positive. The type species is Megalocystidium leucoxanthum (Bres.) Jülich.

features

The annual, resupinate fruiting bodies are up to 1.5 mm thick and are membranous to waxy. The edge is often byssoid or thinned. The hymenium surface is smooth or slightly bumpy.
The hyphae system is monomitic . The hyphae usually have buckles on the septa . In addition to the basidia, there are numerous, long, winding gloeocystids with oily or granular contents. They are sulfo positive. The four-pore basidia are narrow, club-like and quite long. A basal buckle may be present or absent. The more or less thin-walled basidiospores are cylindrical to ellipsoid and smooth, or almost smooth, and have only a small apiculus . They turn bluish black with iodine reagents, but are acyanophilic .

Ecology and diffusion

The representatives of the genus Megalocystidium are white rot fungi that live saprobionic and grow on dead wood (mainly on hardwood). Two species ( Megalocystidium leucoxanthum and Megalocystidium luridum ) prefer the temperate climate zone and occur in North America and Europe. M. leucoxanthum was also found in Africa (Ivory Coast and Gabon) and Thailand. Megalocystidium montanum grows in North America on wood from different species of fir ( Abies concolor , A. lasiocarpa and A. magnifica ), while Megalocystidium wakullum is common in the southern USA (Florida and Mississippi) and grows on hardwood. It was also found in Guadeloupe and Tanzania . Megalocystidium minutisporum (Gabon), Megalocystidium africanum (Central African Republic), Megalocystidium gloeocapitulatum (on Réunion ) occur in tropical and subtropical Africa. Megalocystidium luteocystidiatum has been found in Africa ( Natal , Gabon , Ivory Coast) and Asia (India, Thailand, Taiwan).

Systematics

Fig. 1: Minimum evolution family tree of the Megalocystidium relationship: The bootstrap values ​​are shown next to the branches, the genebank sequence number is shown behind the species name. All further information on the calculation of the tree can be found under the image description.
Fig. 2: Mamximum likelihood family tree of the Megalocystidium relationship

The genus Megalocystidium was proposed by W. Jülich in 1978. It summarized the Gloeocystidiellum luridum and G. lactescens group proposed by J. Eriksson and L. Ryvarden in 1975 in one genus. He placed the three species in his genus: M. leucoxanthum , M. lactescens and M. luridum . Megalocystidium thus contained species with smooth basidiospores, sulfopositive gloeocystids and hyphae with buckles (G. luridum group) and without buckles (G. lactescens group). However, in its original description of the genus, Jülich does not provide any information on the sulfoaldehyde reaction, nor does it specify the characteristics of the genus that differ from closely related genera. This is probably also the reason why many mycologists were skeptical of Jülich's new genus. In 1983 Boidin and Lanquetin put Megalocystidium in synonymy with Vesiculomyces and K. Hjortstam, who in 1987 subjected the genera of corticoid fungi to an extensive revision, put M. leucoxanthum and M. luridum back into the genus Gloeocystidiellum . He also realized that the main characteristics of M. lactescens were similar to those of Gloiothele lamellosa (Henn.) Bres. (of the type species of the genus Gloiothele ). Therefore he placed M. lactescens in the genus Gloiothele . His regrouping was carried out in 2003 by E. and K.-H. Larsson confirmed by rDNA sequence analyzes.

Two features in particular are controversial in the definition of the genre. On the one hand the sulfoaldehyde reaction of the gloeocystids, on the other hand the occurrence of buckles. While most authors define Megalocystidium as a genus with sulfopositive gloeocystidia, Ginns & GW Freeman (1994) name sulfo-negative gloeocystidia as an important generic characteristic. Another main characteristic for them is the occurrence of buckles, an opinion that S.-H. Wu joins in 1996. However, recent molecular biological investigations have clearly shown that buckles as a feature were taxonomically overrated in the past, at least within the pigeon relatives. The different evaluation of the sulfobenzaldehyde reaction is due to the weak or variable reaction in M. leucoxanthum and M. luridum .

In 2003 E. and K.-H Larsson examined the rDNA genes ( 5.8S, ITS2 and LSU-rDNA ) of over 100 mainly corticoid fungi from the order of the pigeon-like. With their work they were able to show that M. leucoxanthum , M. luridum and Gloeocystidiellum wakullum form a community of descent . A closer relationship between M. luridum and G. wakullum had already been established by Boidin and his co-authors, who had examined the rDNA (ITS1, 5.8S and ITS2 rDNA) of numerous corticoid fungi in 1998. The gloeocystid of the subtropical species was described as sulfo-negative in the original description. According to Boidin et al. are they clearly sulfo-positive (albeit weak), which is indicated by EK-H. Larsson is confirmed. In 1996 S.-H. The fungus was placed in the genus Stereum due to the simply septate hyphae, the smooth, amyloid spores and its acanthohyphidia . The resupinate fruiting bodies, the relatively large, smooth, amyloid spores and the weakly sulfoaldehyde-positive gloeocystidia, however, speak for inclusion in the genus Megalocystidium . The fungus differs from the other species of this genus by its acanthohyphids and simply septate hyphae. Should further molecular biological investigations confirm its membership in the genus, Lülich's genus concept would have to be expanded.

species

Today (as of 2014) around 9 species are included in the genus, although some species are controversial and some mycologists have placed them in other genera. Molecular biological sequence data are only available for three of the species listed here.

The species of the genus Megalocystidium
Species name author
Megalocystidium leucoxanthum Yellow and white gloeocystid
bark fungus 		(Bres.) Jülich (1978)
Megalocystidium luridum pale yellow gloeocystid
bark fungus 		(Bres.) Jülich (1978)
Megalocystidium montanum Ginns & GW Freeman (1994)
Megalocystidium luteocystidiatum (PHB Talbot) Sheng H. Wu (1996)
Megalocystidium minutisporum Boidin, Lanq. & Gilles (1997)
Megalocystidium africanum Boidin, Lanq. & Gilles (1997)
Megalocystidium gloeocapitulatum Boidin & Gilles (2000)
Megalocystidium gloeocapitulatum Boidin & Gilles (2000)
Megalocystidium wakullum (Burds., Nakasone & GW Freeman) E. Larss. & KH Larss. (2003)

swell

  • Megalocystidium. In: MycoBank.org. International Mycological Association, accessed February 19, 2013 .
  • A. Bernicchia, SP Gorjón (Ed.): Fungi Europaei . Corticiaceae s. l. tape 12 , 2010.
  • Megalocystidium. Jülich, Persoonia 10 (1): 139 (1978). In: www.indexfungorum.org. Retrieved February 20, 2013 .
  • J. Boidin, P. Lanquetin, G. Gilles: Le genre Gloeocystidiellum sensu lato (Basidiomycotina) . In: Bulletin de la Société Mycologique de France . tape 113 , no. 1 , 1997.

Individual evidence

  1. ^ A b W. Jülich: Studies in resupinate Basidiomycetes - V. Some new genera and species. In: Persoonia . tape 10 , no. 1 , 1978, p. 137–140 ( cybertruffle.org [accessed September 10, 2014] with English and Latin generic diagnosis).
  2. ↑ a b A. Bernicchia, SP Gorjón (ed.): Fungi Europaei Vol.12 . 2010, p. 430 ( mycobank.org [accessed September 10, 2014]).
  3. ↑ a b c SH Wu: Studies on Gloeocystidiellum sensu lato (Basidiomycotina) in Taiwan . In: Mycotaxon . tape 58 , 1996, pp. 57 ( cybertruffle.org [accessed September 10, 2014]).
  4. ↑ A. Bernicchia, SP Gorjón: Fungi Europaei Vol.12 . 2010, p. 430 ( mycobank.org - description of M. leucoxanthum ).
  5. ↑ A. Bernicchia, SP Gorjón: Fungi Europaei Vol.12 . 2010, p. 431 ( mycobank.org - description of M. luridum ).
  6. ^ J. Ginns, GW Freeman: The Gloeocystidiellaceae (Basidiomycota, Hericiales) of North America . In: Bibliotheca Mycologica . tape 157 , 1994, p. 78 ( mycobank.org - description M. leucoxanthum ).
  7. ^ J. Ginns, GW Freeman: The Gloeocystidiellaceae (Basidiomycota, Hericiales) of North America . In: Bibliotheca Mycologica . tape 157 , 1994, p. 78 ( mycobank.org - description M. montanum ).
  8. ↑ J. Boidin, P. Lanquetin, G. Gilles: Le genre Gloeocystidiellum sensu lato (Basidiomycotina) . 1997, p. 71 ( mycobank.org - description by M. minutosporum ).
  9. ↑ J. Boidin, P. Lanquetin, G. Gilles: Le genre Gloeocystidiellum sensu lato (Basidiomycotina) . 1997, p. 61 ( mycobank.org - description by M. africanum ).
  10. ↑ J. Boidin, G. Gilles: Basidiomycètes Aphyllophorales de l'ile de La Reunion. XXI - Suite . In: Mycotaxon . tape 75 , no. 1 , 2000, pp. 357-387 ( cybertruffle.org - description of M. gloeocapitulatum on page 370).
  11. ↑ J. Boidin, P. Lanquetin, G. Gilles: Le genre Gloeocystidiellum sensu lato (Basidiomycotina) . 1997, p. 69 ( mycobank.org - description of M. luteocystidiatum ).
  12. ↑ J. Eriksson, L.Ryvarden: The Corticiaceae of North Europe . tape 3 , 1975, p. 404 ( mycobank.org ).
  13. ↑ J. Boidin, P. Lanquetin: Basidiomycetes Aphyllophorales épitheloïdes étales . In: Mycotaxon . tape 1983 , no. 2 , 1983, p. 492-493 ( cybertruffle.org [accessed September 10, 2014]).
  14. ^ J. Ginns, GW Freeman: The Gloeocystidiellaceae (Basidiomycota, Hericiales) of North America. In: Bibliotheca Mycologica . tape 157 , no. 1 , 1994, p. 118 ( mycobank.org [accessed September 10, 2014]).
  15. ^ J. Boidin, J. Mugnier, R. Canales: Taxonomie moléculaire des Aphyllophorales . In: Mycotaxon . tape 66 , 1998, pp. 464 ( cybertruffle.org ).
  16. ↑ Ellen Larsson, Karl-Henrik Larsson: Phylogenetic relationships of russuloid basidiomycetes with emphasis on aphyllophoralean taxa . In: Mycological Society of America (Ed.): Mycologia . tape 95 , no. 6 . Lawrence 2003, p. 1037-1065 ( mycologia.org ).

Web links

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