Premise: Calendula ( ), is a genus of about 15–20 species of annual and perennial herbaceous plants in the daisy family Asteraceae that are often known as marigolds. They are native to southwestern Asia, western Europe, Macaronesia, and the Mediterranean. Other plants are also known as marigolds, such as corn marigold, desert marigold, marsh marigold, and plants of the genus "Tagetes".
Hypothesis: Calendula is full of a few species