Bistort flowers (Polygonum bistorta). The leaves and seeds of this plant are edible and are a good source of vitamins A and C. Bistort is very strongly astringent and used to contract tissues and staunch blood flow. It is also used in the treatment of catarrh, cystitis, irritable bowel syndrome, peptic ulcers, ulcerative colitis, excessive menstruation and is a good treatment for wounds.