He picked up an "abetter" organism on a survey to 1212 Muscae IV: the alien mycete chummed up with a more normal fungus, something a lot of us carry in us routinely, and the two potentiated one another and infected his fingernails badly.

There's one spot here"-for a moment he riffled through the cassettes on his desk, then gave it up-"never mind the reference, but there's at least one mycete listed as four discrete species, and another three of what look like different species to me seem to have been mistaken for different sporulating forms of the same one.