Tarragon is an herb which is especially known from the classical (French) kitchen. It originates from Central Asia and is in Europe for culinary use since the Middle Ages. Both the leafs as the flowers can be used for consumption.
Ruccola is mainly used for flavouring salads and lettuce, but it can also be stewed. The seeds can be eaten with bread. Ruccola has a walnut-like taste, sometimes a little bitter, and containts much vitamin C. The usage of this herb salads and lettuce is a typical Toscan thing.