Setaria macrostachya and S. vulpiseta have been treated as distinct species by most authors since they were first described more than 180 years ago. In three recent publications, however, S. macrostachya was listed as a synonym of S. vulpiseta. The present study, which included the examination of some 350 herbarium specimens, has convinced us that these two species are as distinct as many others in the genus, and should continue to be recognized as separate taxa.
Communicating Editor: Jerrold Davis