St. John's Wort (Hypericum perforatum) is an ancient medicinal plant. It is known for the mild antidepressant properties of its bioactive compound hypericin, which is produced in the dark glands of the plant. By investigating the flowers of St. John's Wort, researchers identified genes involved in dark gland development and the biosynthesis of hypericin. The findings were published in the Plant Biotechnology Journal.