Woad is a tall, erect plant of the mustard family, grown as a source of the blue dye indigo. The plant is native to Europe and Asia but has been introduced into other countries. Woad grows to about 8 feet (2.5 meters) high. The lower leaves are downy and lance-shaped, and the upper leaves clasp the stem with an arrow-shaped base. The plant produces clusters of small, four-petaled yellow flowers. The seed pods dangle like earrings.
The leaves are used to make the dye. The dye was used by the ancient Britons, who painted their bodies blue to frighten away their enemies.
