Rye

Rye is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than other cereals, making it useful in those regions; its vigorous growth suppresses weeds and provides abundant forage for animals early in the year. It is a member of the wheat tribe (Triticeae) which includes the cereals wheat and barley. It is likely that rye arrived in Europe as a secondary crop, meaning that it was a minor admixture in wheat as a result of Vavilovian mimicry, and was only later cultivated in its own right.

Source: Wikipedia