Polygonum persicaria Cockscomb
This plant is very common in humid, damp areas and is native to Europe and Asia. It can grow as tall as 80cms and flowers from July to November. It's leaves contain tannins and are effective against diarrhoea. The leaves can also be used in salads, as well as applying to the skin for sores and skin ulcers. They contain a yellow dye when infused.