Electron microscopic study of Conidium ontogeny in Coniothyrium cupressacearum (Coelomycetes)

Coniothyrium cupressacearum (Morelet) Morelet, exhibiting annellated conidiogenous cells in light microscopy, was examined by transmission electron microscopy. Since the conidial wall is formed de novo, i.e. not continuous with a pre-existent layer of the conidiogenous cell wall, the conidiogenesis is clearly phialidic. After production of a number of conidia, a percurrent proliferation of the phialide collar occurs; this explains the annellated appearance. The annellide is not considered to be a special kind of conidiogenous cell but a variation of either the phialide or the aleuriophore.