Vervain

имя существительное [ботаника] вербена

Большой англо-русский словарь

Vervain

noun Etymology: Middle English verveine, from Anglo-French, from Latin verbena leafy branch; akin to Latin verber rod, Lithuanian virbas, and perhaps to Greek rhabdos rod any of a genus (Verbena of the family Verbenaceae, the vervain family) of chiefly American plants having bracted spicate flowers, a corolla with a 5-lobed limb, and a fruit that separates into four nutlets

Merriam-Webster's Collegiate Dictionary