Rye
Rye belongs to the family Gramineae. It is classified as Secale cereale.

Rye is native to temperate Eurasia where it is most heavily used as a bread grain (mixed with other grains). Rye was first cultivated rather late in human history, perhaps as recently as 2000 to 3000 years ago. Rye flour is also heavier and darker in color than most other flours, which is why it produces dark, dense loaves. There are several different types of rye flour, the most common of which is medium rye flour, available in most supermarkets. Light or dark rye flours, as well as pumpernickel flour (which is dark and coarsely ground), are available in health-food stores and some supermarkets. Milled from a hardy cereal grass, rye flour contains less gluten (protein) than all-purpose or whole-wheat flour.