Saffron is a spice derived from the flower of the saffron crocus (Crocus sativus). Crocus is a genus in the family Iridaceae. A C. sativus flower bears three stigmas, each the distal end of a carpel. Together with the styles — stalks that connect the stigmas to their host plant — the dried stigmas are used in cooking as a seasoning and colouring agent. Saffron, long the world's most expensive spice by weight, is native to Southwest Asia.