Sorrel (genus Rumex) – The species of this member of the buckwheat family have leaves shaped similar to spinach, but are easy to distinguish because of their tart acidity caused by high concentrations of oxalic acid. They can be eaten raw in salads or cooked in sauces and soups. Rumex scutatus, also known as French sorrel, sour dock, and sour grass, is preferred. The more common Rumex acetosa is also known as dock sorrel and spinach dock. All are evergreen perennials that do well under most conditions.