A Rosid Is a Rosid Is a Rosid . . . or Not

The current structure of 583 Magnoliopsida (Dicotyledons) and 584 Liliopsida (Monocotyledons) in the Dewey Decimal Classification (DDC) system reflects changes made when the life sciences were thoroughly revised in 1996. Since that time, considerable progress has been made in the phylogenetic classification of angiosperms (flowering plants). In particular, APG III, the 2009 version of the classification developed by the Angiosperm Phylogeny Group, is finding use as a tool to organize both botanical information and botanical collections. The Dewey Editorial Office has received a request to revise 583–584 in light of this taxonomy ―as appropriate‖; relevant revisions would be likely to include both structural and terminological changes. In deciding how to provide accommodation for APG III, the Dewey editorial team must address many issues: Is APG III now stable enough and accepted broadly enough to be adopted as the basis for a major revision of the DDC? Should revisions in 583–584 be coordinated with parallel revisions in other parts of the life sciences? What revision strategies can be considered in revising 583-584 to accommodate APG III? What are their various strengths and weaknesses? How have other major classification schemes (e.g., the UDC) accommodated APG III? Discussion of these issues is guided by the principles (―editorial rules‖) that govern development of the DDC.