For most taxa included within the Taxonomic Data Center, a high degree of functional synonymy is presented by including only “manual-level” synonyms rather than detailed or “monographic-level” synonyms. For certain genera such as Salix, Lupinus, Crataegus, Rubus, Antennaria, and Galium, however, and for certain Hawaiian plant genera, more complete synonymy is included to provide an accurate understanding of the elements in these confusing and controversial genera. Despite the more detailed treatment of these genera, the general intent of the Synthesis is to account for only the accepted names that appear in current standard floras, monographs, revisions, and other recent floristic literature. To have included “monographic-level” synonymy would have otherwise added nearly 270,000 more names and tripled the number of names!
Although I recognize that many of the names listed in synonymy are illegitimate under the current International Code of Botanical Nomenclature, I have nevertheless included them and show their proper disposition, since they appear in many of our floras, manuals, and monographs. Recognizing also the misuse, misapplications, or differences in applications of certain synonyms, I opted to use the abbreviations auct. non and (pro parte) for such names. In a few cases, the names of certain taxa (e.g., Taraxacum officinale, Bidens spp.) are retained in spite of potential nomenclatural or taxonomic problems, which may ultimately render such names illegitimate or otherwise inappropriate for use. Until more complete understanding of these names and the taxa that they represent are available, their traditional usage is maintained.