Members of the Monoblepharidomycetes have a filamentous thallus that is either extensive or simple and unbranched. They frequently have a holdfast at the base. In contrast to other taxa in their phylum, some reproduce using autospores, although many do so through zoospores. Oogamous sexual reproduction may also occur. In addition to the type genus, the order Monoblepharidales includes Harpochytrium and Oedogoniomyces.