(This article is about the plant genus. For the species in this genus that is widely used in herbal medicine, see Bacopa monnieri.) Bacopa is a genus of 70–100 aquatic plants belonging to the family Plantaginaceae. It is commonly known as Waterhyssop (or Water Hyssop, though this is more misleading as Bacopa is not very closely related to hyssop but simply has a somewhat similar appearance).