Summary A leaf-spotting fungus identifiable with Sphaerella mappiae Petch is described on Mappia ovata Miers in Ceylon. In two successive years the perithecia were observed with adherent, extruded spore masses in which the majority of the ascospores had become two- to three-septate and had budded off large numbers of ‘sprout cells’. The significance of this behaviour is discussed, with the conclusion that the species should be transferred to the genus Sphaerulina. The new combination Sphaerulina mappiae (Petch) Bond is formally proposed, the diagnosis being slightly amended and a new homoeotype specified. No connexion has been found with the conidial fungus Septogloeum mappiae Petch, on the same host.