Allionia, commonly known as windmills or trailing four o'clock, is a genus of two species widespread in the western hemisphere. They are unusual in their blooms, which actually consist of three separate flowers appearing to be a single flower. The range of Allionia incarnata L. includes North America, the West Indies, Central America, and South America, while Allionia choisyi Standley is more restricted in North America, occurring in Arizona, Utah, New Mexico, and Texas. Linnaeus named the genus after Italian botanist Carlo Allioni (1725-1804).