All members of their phylum were once thought to be related to the Endogonaceae, but have been found through molecular sequencing data, to be a closer relation to the Dikarya.[3] Their fossil record extends back to the Ordovician period (460 million years ago).[2]
Meiosis
Glomerales fungi were thought to have reproduced clonally for several hundred million years and are therefore an ancient asexual lineage.[4] However, homologs of 51 meiotic genes, including seven genes specific for meiosis, were found to be conserved in the genomes of four Glomus species.[4] Thus it now appears that these supposedly ancient asexual fungi may be capable of meiosis and perhaps also of a cryptic sexual or parasexual cycle.[4]
Orthography
The family name Glomeraceae upon which this order level name is based, was incorrectly spelled 'Glomaceae', hence the order name was incorrectly spelled 'Glomales'. Both are correctable errors, to Glomeraceae and Glomerales, as governed by the International Code of Botanical Nomenclature. The incorrect spellings are commonplace in the literature.
^J.B. Morton (1990). "Revised classification of the arbuscular mycorrhizal fungi (Zycomycetes): a new order, Glomales, two new families, Acaulosporaceae and Gigasporaceae, with an emendation of Glomaceae". Mycotaxon. 37: 473.
^ abC.J. Alexopolous, C.W. Mims & M. Blackwell (2004). Introductory Mycology (4th ed.). Hoboken NJ: John Wiley and Sons. ISBN0-471-52229-5.
