What is the difference between French Marigold and Calendula?
French marigold belongs to the Tagetes genus in the sunflower family (Asteraceae or Compositae). It is an American native.
Marigold, pot marigold (Calendula) is a genus in the daisy family Asteraceae. They are native to southwestern Asia, western Europe, Macaronesia, and the Mediterranean. Calendula is edible. Most French marigold varieties are considered not edible. But the there species which are used in cooking. You can read more in this article about Calendula and French marigold.