This is the fourth of a series of annual supplements to the Index Kewensis. It will provide more up-to-date information than has hitherto been available for the five-yearly supplements that have been issued since the appearance of the original work in 1895. As in the five-yearly supplements, information is included on new and changed names of seed-bearing plants at the level of family and below. There is an additional section listing new and overlooked generic names. In this volume there are no entries for ferns at the ranks above genus.