Glomeromycota (informally glomeromycetes) is one of seven currently recognized divisions within the kingdom Fungi, with approximately 230 described species. Members of the Glomeromycota form arbuscular mycorrhizas (AMs) with the roots or thalli (e.g. in bryophytes) of land plants. Geosiphon pyriformis forms an endocytobiotic association with Nostoc cyanobacteria, and is the only member of the Glomeromycota known not to form arbuscular mycorrhiza in association with plants. AM formation has not yet been shown for all species. The majority of evidence shows that the Glomeromycota are symbionts with land plants (Nostoc in the case of Geosiphon) for carbon and energy, but there is recent circumstantial evidence that some species may be able to lead an independent existence. The arbuscular myco