​RUE (Fr. rue, Lat. ruta, from Gr. ῥυτή, the Peloponnesian word for the plant known as πήγανον), the name of a woody or bushy herb, belonging to the genus Ruta, especially Ruta graveolens, the “common rue,” a plant with bluish green spotted leaves and greenish yellow flowers. It has a strong pungent smell and the leaves have a bitter taste. The plant was much used in medieval and later medicine as a stimulative and irritant drug. It was commonly supposed to be much used by witches. From its association with “rue,” sorrow, repentance (O. Eng. hréow, from hréowan, to be sorry for, cf. Ger. reuen), the plant was also known as “herb of grace,” and was taken as the symbol of repentance.