The genus Microascus is redescribed. It now comprises species with ostiolate, dark ascomata and small, asymmetrical, one-celled, smooth, yellow ascospores with a single germ pore at the base. The conidial states fit Scopulariopsis or Wardomyces. A key is given to 11 accepted species and two similar species of Kemia and Chaetomium. A fungus isolated from soil in West Africa is described as Microascus senegalensis. A list of 7 excluded or doubtful species is added.