Gypsywort

Lycopus europaeus (Gypsywort, Gipsywort, Bugleweed, European Bugleweed, Water Horehound, Ou Di Sun) is a perennial plant in the Lycopus genus, native to Europe and Asia, and naturalized in the United States.

Gypsywort grows primarily in wetland areas. Its root is a rhizome. It is in flower from June to September, and produces seeds from August to October.

Etymology and folklore
It is reputed to have medicinal qualities   and has been used by various peoples as an astringent, cosmetic, douche, narcotic and refrigerant. It has also been used to treat fever, hypothyreosis, sores and wounds. Several research studies have been undertaken on the properties of this plant.

The name Gypsywort comes from the belief that Gypsies were reputed to stain their skin with the juice of the plant, althgough Howard (1987) states that they used it to dye their linen.