Taxonomy is the branch of science concerned with classi- fying organisms: drawing the line between cats and dogs, fish and fowl, animals and vegetables. Modern taxonomic work is built on a hundreds-year-old tradition of qualitative research and description. There are aspects of this work that illustrate the pervasiveness and difficulty of a particular kind of qualitative data wrangling, which we call semantic refactoring: the review, normalization, and re-engineering of semantic structures. Because taxonomic work is con- ducted over long time spans, the processes underlying se- mantic refactoring become more visible. An examination of taxonomic data practices may inform our understanding of how (and if) collections of qualitative data scale, particularly when collaboratively created.NSF ABI Grant 1356515.Ope