I thought that I would also mention that in addition to The Plants List, the eBird project also uses on overlapping concepts in its bird list (it does have concepts for common hybrids)
What is clear to me is that you cannot create graphs like these if every observation can have X number of species (especially those that overlapping ) without any indication which is is the most appropriate one.
eBird Occurrence Maps Northern Cardinal http://ebird.org/content/ebird/about/occurrence-maps/northern-cardinal
NCBI is also similar.
Perhaps a member of the consensus committee can comment?
-- Pete ------------------------------------------------------------------------------------ Pete DeVries Department of Entomology University of Wisconsin - Madison 445 Russell Laboratories 1630 Linden Drive Madison, WI 53706 Email: pdevries@wisc.edu TaxonConcept http://www.taxonconcept.org/ & GeoSpecieshttp://about.geospecies.org/ Knowledge Bases A Semantic Web, Linked Open Data http://linkeddata.org/ Project --------------------------------------------------------------------------------------