Geosiphon

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Geosiphon pyriformis

Kingdom:	Fungi
Division:	Glomeromycota
Class:	Glomeromycetes
Order:	Archaeosporales
Family:	Geosiphonaceae
Genus:	Geosiphon

Species

Geosiphon pyriformis

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

1 Life cycle
2 Reproduction
3 Somatic structure
4 References

[edit] 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, then 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.

[edit] 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.