Verbena, a genus of plants of the natural order Verbenaceæ. The genus consists of numerous species of herbs or shrubs which inhabit the tropical and subtropical parts of the world; most numerous in America, more rare in Asia and Africa. One species, the Common Vervain or Vervain, is a native of the southern counties of England, and is occasionally met with in Ireland and in Scotland. They have opposite leaves, sessile bracteated flowers in simple or panicle spikes, terminal or axillary; a tubular five-toothed calyx, tubular corolla more or less curved with a spreading limb, generally unequally lobed; four stamens, included in the tube, the upper pair sometimes without anthers; a slender style with capitate stigmas. The ripe fruit splits into two or four nutlets, each containing one seed. The genus is more remarkable for the beauty of a number of the species, which under cultivation have given origin to numerous varieties greatly prized for their brilliant coloured flowers, than for other virtues, although formerly the British species was credited with potent medicinal qualities, particularly in ailments of the bladder and in the cure of defective vision, which, however, appear to have been purely imaginary. It was also worn on the person as a protection against blasts and to promote general good-fortune, for which purpose it was gathered with special observances and ceremony. The Lemon-scented Verbena is Aloysia citriodora, which belongs to the same natural order; but the perfumers' Oil of Verbena is derived from the Lemon-grass (q.v.).