Glomus macrocarpum was discovered forming sporocarps at or near the surface of woodlands in France in the early 1880s by the Tulasne brothers. They described it originally (as Glomus macrocarpus) in a new genus (1845), Glomus, but soon afterwards (1851), they moved it into an already existing genus, Endogone, as E. macrocarpa. This was a mistake, as the two genera are phylogenetically very distant, but it was not until 1974 that the species was moved back into Glomus. It is the ‘type species’ that defines the genus. This fungus is now known to form arbuscular mycorrhizas, but when it was first discovered, and for more than a further century, nothing was known about its life habits.