Geosiphon

Taxobox | name = "Geosiphon pyriformis"
regnum = Fungi
divisio = Glomeromycota
classis = Glomeromycetes
ordo = Archaeosporales
familia = Geosiphonaceae
genus = "Geosiphon"
subdivision_ranks = Species
subdivision = "Geosiphon pyriformis"

"Geosiphon" is a genus of the phylum Glomeromycota, Order Archaeosporales, Family Geosiphonaceae.

Life cycle

"Geosiphon pyriformis" is known for being the symbiont of "Nostoc". The "Geosiphon"-"Nostoc" symbiosis, as by modern definitions, is not a lichen, since it is an intracellular association. Also, by functional and evolutionary implications it is more comparable to the arbuscular mycorrhiza symbioses than to lichens.

The "Geosiphon"-"Nostoc" symbiosis is the only known fungal endosymbiosis with cyanobacteria and is characterised by a "siphonal bladder" that is made of a swollen fungal hypha, 0.5-2 mm in size and growing on the soil surface. The upper 2/3 of the "bladder" contains the "Nostoc" filaments and Nostoc heterocysts, the lower 1/3 is filled with lipid droplets.

Reproduction

The fungal spores are 250 micrometres in diameter, formed at the end of one hypha, or intercalarly (within a hyphae) and resemble those of members of the Glomeromycota.

omatic structure

"Geosiphon" has a specialised bladder used to harbour cyanobacteria. "Geosiphon pyriformis" is not known to form arbuscular mycorrhiza.

References

http://www.geosiphon.dehttp://www.amf-phylogeny.com

*C.J. Alexopolous, Charles W. Mims, M. Blackwell, "Introductory Mycology, 4^th ed." (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5