Abstract: A new order is introduced (Jahnulales) to accommodate ascomycetes with stalked/sessile and dimorphic ascomata, hyphal stalk cells that are ca 40 μm wide, and ascospores that are unequally 2-celled with or without various types of appendages or sheaths. The order includes a single family, the Aliquandostipitaceae, and has affinities with the Pleosporales within the Dothideomycetes. Studies on freshwater ascomycetes in Egypt and Thailand yielded one new genus Patescospora, and Jahnula siamensiae sp. nov., and the new combination J. sunyatsenii (syn. Aliquandostipite sunyatsenii) is made based on molecular results.