Spanish Needle

In my front yard, I saw one, tall, white flower, growing amid a large area, of low growing purple flowers. Lot's of low growing purple flowers, and among them, one, tall, white flower, was growing. This tall, white flower, had six, white petals, and a round, yellow center. Each flower petal, was divided into three sections. This, tall, white flower, was one and one half of an inch high, and one and one half of an inch wide. The stem, was green in color. The leaves, was also green in color. The outside of the leaves, was serrated. Kingdom: Plantae.