INDEX KEWENSIS
Index Kewensis is a world list of names of seed-bearing plants with bibliographic references to their first publication. It is not a list of accepted names, and not all of the names listed are validly published according to the rules of the International Code of Botanical Nomenclature (ICBN). It should not be considered an authority regarding synonyms, in spite of the fact that synonyms are listed for many genera and species. IKew is strictly an index.
Compilation of IKew began in January 1882 and was financed by Charles Darwin who stipulated in his will that the work would continue to be funded by his estate after his death. The starting point of the index is the publication date of the first edition of Linnaeus’ Systema naturae, 1735. The sources which Linnaeus included in writing his Systema were not delved into, but credit (authorship) is given for those names he used which did not originate with him as follows: Linnaeus ex Tournefort (L. ex Tourne.), for example.
Authors of Plant Names is a list of authors of plant scientific names, giving the recommended standard forms of those authors’ names, including abbreviations. APN’s stated intention is "to include all authors who have published names of plants covered by the International Code of Botanical Nomenclature." "Authors who have published names invalidly (but effectively) are included, since they may appear in an ‘ex’ citation" (such as "Jones ex Smith").