Ascospore development in Ceratocystis sensu lato (Fungi): a review

Ceratocystis. Ceratocxstiopsis and Ophiostoma are important pathogens of trees and some agricultural crops and have recently been found on proteas and forest trees in South Africa. Taxonomic controversy exists regarding these genera and ultrastructural studies on the development of asci, uniquely shaped ascospores and centrum structure are inadequate. This rev iew summarises current knowledge of ascospore shape and development of the centrum obtained from light and electron microscope studies of Cemtocystis sensu lato. Important questions requiring further investigations are outlined. It is furthermore proposed that additional ultrastructural studies are required to clarify the current taxonomic disagreement in this group. Such studies could also identify relationships between these fungi and other Ascomycetes.