Rorippa nasturtium~aquaticum Watercress
This aquatic plant is found all over Europe and Asia in streams, pools and damps places. It is now cultivated worldwide. It flowers from February to August and can spread to several metres. It can grow to an height of 50cms. Synonym: Nasturtium officinale. It is one of the oldest known leaf consumed by humans. It thrives in water that is slightly alkaline, and it contains iron, calcium, iodine and manganese.