“The first duty of a plant collector on visiting a new place is to see the markets to gain clues to his future work and, if it is native medicinal plants, call upon the females. In Mexico they are the magicians of medical lore and cures handed down from one to the other. Perhaps their [remedy] may be as correct at least as the average patent medicine of the United States.” Dr. Edward Palmer, 1878, in San Luis Potosí, Mexico.