By Amelia R. Cohn Naturtium officinale, commonly known known as watercress, is is one of the oldest known salad greens consumed by humans, sharing the Brassicaceae family with collards, kale and broccoli. This semi-aquatic plant is high in many vitamins and minerals. It contains heart-rate and blood-pressure regulating potassium as well as the B-complex vitamins that are crucial …