fleabane, in botany: A genus of the polygamia superflua order, belonging to the syngenesia class of plants; and in the natural method ranking under the 49th order, Compositae. The receptacle is naked; the pappus hairy; the florets of the radius are linear, and very narrow. There are five species; of which the most remarkable is the viscosum, or male fleabane of Theophrastus, and greater fleabane of Dioscorides. It is a native of the south of France and Italy; and hath a perennial root, from whence arise many upright stalks near three feet high. The leaves in warm weather sweat out a clammy juice; the flowers are produced single upon pretty long footstalks, are of a yellow colour, and have an agreeable odour. The plants are easily propagated by seeds; and thrive best in a dry soil and sunny exposure.