Common Buckwheat (or buckwheat) is a plant. It is often seen as a cereal. Buckwheat is not a true grass. It is not related to wheat, because wheat is a true grass. Buckwheat seeds look like small beech tree seeds. Both seeds have three sides. Beech is also called buck. This is how buckwheat got its name - buckwheat is a plant that is used like wheat and whose seeds look like "buck", or beech seeds.