The Four Karisalai of Siddha: Why Flower Colour Changed the Prescription Ask for karisalankanni at a shop in Tamil Nadu and you will almost certainly be handed one thing: a dark-green powder milled from a small, sprawling plant with tiny white flowers. It is a fine herb, and it deserves its reputation. But it is one of four. Siddha’s materia medica does not treat karisalai…