Aak ka Phool refers to the flower of the Calotropis plant, also known as Calotropis gigantea or Calotropis procera, and commonly called "Aak" or "Madar" in Hindi.The flowers are typically light purple or lavender, with a waxy texture and a star-like shape. Aak is a hardy shrub that grows wild in dry areas of India and other tropical regions.Used in Ayurveda and traditional healing systems.