In culture, conidiogenesis in Monotosporella sphaerocephala, formerly considered a typical annellophorous species, was inconsistent with the definition of an annellophore. Proliferation involved percurrent growth of intraconidiophore hyphae through the lower layer of bilayered conidium-delimiting septa. A lower septal layer played no role in the formation of a subsequent conidium. Angularly displaced conidia were commonly held on the side of conidiophores by lower septal layers when the layers of conidium-delimiting septa failed to split after conidium secession. Conidium-delimiting septa were laid down early in conidiogenesis, and conidium initials thereafter underwent a great size increase before they seceded as conidia, events inconsistent with the definition of blastic conidium ontogeny made at the Kananaskis Conference on Taxonomy of Fungi Imperfecti.