Modelling taxa is a bit trickier. I've sketched my ideas for distinguishing name strings and taxonomic names earlier. That's the easy stuff. What about "taxonomic concepts" and "OTUs"? As a first pass, I'm looking at linking taxon names to classifications via GUIDs.

Quick note to self, having stumbled on the Wikipedia page on transitive reduction. Given a graph like this: the transitive reduction is: Note that the original graph has an edge a -> d, but this is absent after the reduction because we can get from a to d via b (or c). What's the point?