There are repeated references to nasturtium leaves and buds in salads and pickles from mediaeval times up to Mrs.B, while Glasse 1747 suggests the flowers as a decoration on salmagundi, but it is often difficult to know which of two plants is being referred to.
The flowering nasturtium, Tropaeolum majus (known as Indian cress or monks cress) is now almost always a garden ornamental, but the peppery leaves have been used in salads, and the immature seed buds as an alternative to capers.
The, unrelated, saled cress plant Nasturtium microphyllum, likewise has a peppery-tasting leaf and is widely used in salads, soups and other dishes and as mustard and cress