Glomeromycota

[8] The Glomeromycota have generally coenocytic (occasionally sparsely septate) mycelia and reproduce asexually through blastic development of the hyphal tip to produce spores[2] (Glomerospores,blastospore) with diameters of 80–500 μm.

[13] In addition, new data also suggests that AM fungi host plants also secrete chemical factors that attract and enhance the growth of developing spore hyphae towards the root system.

[14] The necessary components for the colonization of Glomeromycota include the host's fine root system, proper development of intracellular arbuscular structures, and a well-established external fungal mycelium.

The penetrating hyphae develop a highly branched structure called an arbuscule, which has low functional periods before degradation and absorption by the host's root cells.

[15] Distinguishing features such as wall morphologies, size, shape, color, hyphal attachment and reaction to staining compounds allowed a phylogeny to be constructed.

[17] Following broader reviews that cleared up the sporocarp confusion, the Glomeromycota were first proposed in the genera Acaulospora and Gigaspora[18] before being accorded their own order with the three families Glomaceae (now Glomeraceae), Acaulosporaceae and Gigasporaceae.

[2] This new classification includes the Geosiphonaceae, which presently contains one fungus (Geosiphon pyriformis) that forms endosymbiotic associations with the cyanobacterium Nostoc punctiforme[23] and produces spores typical to this division, in the Archaeosporales.

[26] This gene is highly conserved and commonly used in phylogenetic studies so was isolated from spores of each taxonomic group before amplification through the polymerase chain reaction (PCR).