Allium is a genus of flowering plants. It contains garlic, leek, onions and chives. There are hundreds of species, some of which have been cultivated for much of human history. Today, about a dozen species are economically important. The type species of the genus is "Allium sativum", commonly known as "garlic". The taxonomy of "Allium" is difficult, because the boundaries between species are often unclear. For this reason, the number of recognised species varies between 260, and 860. Most people think there are about 750 species.