Nastertium flower at Wylam, Northumberland
Nasturtium (/nəˈstɜːrʃəm/) is a genus of seven plant species in the family Brassicaceae (cabbage family), best known for the edible watercresses Nasturtium microphyllum (Rorippa microphylla) and Nasturtium officinale (R. nasturtium-aquaticum). Nasturtium was previously synonymised with Rorippa, but molecular evidence supports its maintenance as a distinct genus more closely related to Cardamine than to Rorippa sensu stricto (Al-Shehbaz & Price, 1998; Al-Shehbaz, Beilstein & Kellogg, 2006). Watercress or yellowcress is a common name for plants in this genus.