The order Pleosporales is a large and diverse group of fungi within the class Dothideomycetes (phylum Ascomycota). Members of this order are mostly saprobic, living on decaying plant material, though many are also important plant pathogens causing diseases such as leaf spots, stem cankers, and blights. Pleosporales species are characterized by their bitunicate asci (double-walled spore sacs) and typically produce darkly pigmented, multicellular ascospores, often with septa. They exhibit a wide range of ecological roles, including endophytic, pathogenic, and occasionally lichenized lifestyles. This order is highly diverse morphologically and genetically, and its taxa are found worldwide in terrestrial and sometimes aquatic habitats.