Developmental stages in mitospore production in Pseudocercospora musae were examined by differential interference contrast light microscopy, scanning electron microscopy, and transmission electron microscopy. Mitosporogenous cells consistently originated directly from upper stromatic cells. Concentric bodies were found in both stromatic and mitosporogenous cells. The cell wall of stromatic cells, mitosporogenous cells, and mitospores, consisted of two layers. Mitospore ontogeny was found to be holoblastic and mitospore secession schizolytic. After liberation, the mitosporogenous cell apex and the mitospore base exhibited a half septum consisting of one layer. A central pore, occluded by a Woronin body, was observed in the mitosporogenous locus. Mitosporogenous cells proliferated percurrently. The morphological characteristics of the apex of mitosporogenous cells and the base of liberated mitospores in P. musae is of fundamental value in defining unthickened scars as important criteria for generic separation within the Cercospora-like generic assemblage.