Why do people wear daffodil?

According to legend, St. David (the patron saint of Wales) was getting ready for a battle that took place in a leek field. He told his Britons to wear a leek in their caps to reduce casualties from "friendly fire", since their enemy, the Saxons, looked like their brothers. This produced a defining victory for the Britons. Today, on March 1st, Welsh people wear the leeks in remembrance. Some will wear the daffodil, since the common Word for leek and daffodil is the same. Daffodil has become the National Flower of Wales.