This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Verbena communis fiore caruleo C. B. Hierobotane, herba sacra, herba cephalalgia & Perifterium quibusdam. Verbena officinalis Linn. Vervain: a plant with wrinkled, oblong, ob-tuse leaves, deeply jagged and indented, set in pairs on the stalks, the upper ones divided into three segments: on the tops of the branches appear irregularly labiated blue flowers, in long spikes, without any leaves among them, followed each by four seeds inclosed in the cup. It is annual, grows wild in uncultivated places, and flowers in July or August.
This herb has been celebrated for abundance of virtues, for which its sensible qualities afford little or no foundation. It has no remarkable smell, and hardly any taste.