According to Redhead and collaborators (2001), coprinoid mushrooms must now be distributed among four genera: Coprinus, Parasola, Coprinopsis, and Coprinellus. While the researchers found physical features that, for the moment, appear to allow separation of these genera, the genera are defined by DNA results and we should not expect the correspondence of physical features to be anything more than coincidental--which means that exceptions may arise. The researchers changed genus names for a large number of mushrooms that have not been subjected to DNA analysis (as well as many that have), on the assumption that the apparent morphological separators among mushrooms that have been tested will remain viable when the rest of the former coprinuses are tested (mushroomexpert.com).