Verbena bonariensis, the purpletop vervain, clustertop vervain, Argentinian vervain,[2] tall verbena or pretty verbena, is a member of the verbena family cultivated as a flowering annual or herbaceous perennial plant. In USA horticulture, it is also known by the ambiguous names purpletop (also used for the grass Tridens flavus) and South American vervain (which can mean any of the numerous species in the genus Verbena occurring in that continent). For the misapplication "Brazilian verbena" see below.