"Nasturtium" (nasus tortus) is Latin for nose twister, and watercress is a perennial of the nasturtium family. Watercress is high in Vitamins A and C, iron and other minerals, and is historically known as a blood purifier. It is also a popular filling for elegant tea sandwiches.
Watercress must be quite peppery in flavor if it's a nose-twister. I've never had it, and I have even less desire now to try some after learning that. Now every time I pass a tea room I'm going to think of them as serving "nose-twister" sandwiches. I won't be able to stop picturing those dainty little sandwiches on delicate china plates, with pairs of gigantic scary pliers emerging from between the pristine white slices of bread waving about seeking my nose and snapping their jaws menacingly.