The first demonstration of action potentials in plants was of those that control the rapid movements of the trap of the carnivorous plant Dionaea. The experiments in which physician John Burdon-Sanderson made this discovery were stimulated by conversations with Charles Darwin (1). As a result of these discussions, Darwin sent Burdon-Sanderson on September 8, 1873 “two plants with five goodish ... [Show full abstract] leaves” (2). Burdon-Sanderson, using a galvanometer, recorded action events as currents from the surface of stimulated traps and demonstrated for the first time that these signals are not unique to the animal kingdom (3). In 1876 (4) he used a capillary electrometer to measure the events as action potentials. Only in posthumously published letters is Darwin’s role in this work recorded, but it must be included as one of Darwin’s significant contributions to the understanding of plant movements.