One of the mechanisms that plants have evolved to trigger the onset of flowering is vernalization, where a plant requires exposure to an extended period of low temperature in winter before it can flower in the spring. A range of species use this response, including the laboratory model plant Arabidopsis and the commercially important cereals, wheat and barley. Vernalization has all the hallmarks of an epigenetic phenomenon—the vernalized state is reset each generation, there is no transmissible signal (cell autonomous mechanism), and there is mitotic inheritance of the vernalized state through a cell lineage.