Aspergillus (/ˌæspərˈdʒɪləs/) is a genus consisting of a few hundred mould species found in various climates worldwide. Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Micheli was reminded of the shape of an aspergillum (holy water sprinkler), from Latin spargere (to sprinkle), and named the genus accordingly. Today, aspergillum is also the name of an asexual spore-forming structure common to all Aspergillus species; around one-third of species are also known to have a sexual stage.