Foxglove, the source for digitalis. Dr. William Withering wrote a pamphlet upon its uses. (Withering did not discover foxglove; it had been known in folk medicine for some time; that said, he did experiment with it in a variety situations, so he did confirm and expand its uses.) Altho’ both were members of the Lunar Society that met at Matthew Bolton’s house (usually) in Soho, just on the edge of Birmingham, Withering and Darwin did not see eye to eye on the use of digitalis or opium.