Rorippa nasturtium-aquaticum (Watercress) is a widespread and very common aquatic weed. It grows in ponds, ditches, slow moving creeks and rivers and sometimes in mud. The habitat combined with the compound leaves with large (~10 cm long), fairly round leaflets make it distinctive. Some Cardamine species have similar leaf shape, but much smaller leaves. The flowers are white and occur in inflorescences at the ends of the stems.