Argemone mexicana (Mexican Poppy, Mexican Prickly Poppy, Flowering Thistle, Cardo or Cardosanto) is a species of poppy found in Mexico and now widely naturalized in many parts of the world. An extremely hardy pioneer plant, it is tolerant of drought and poor soil, often being the only cover on new road cuttings or verges. It has bright yellow latex. It is poisonous to grazing animals, and it is rarely eaten, but it has been used medicinally by many peoples, including those in its native area, as well as the Natives of the western US, parts of Mexico and many parts of India. In India, during the colorful festival Holika Dahan, adults and children worship by offering flowers, and this species is in its maximum flowering phase during March when the Holi festival is celebrated. It is also referred to as “kateli ka phool” in India.