Calendula n. : A genus of composite herbaceous plants. One species, Calendula officinalis, is the common marigold, and was supposed to blossom on the calends of every month, whence the name.

Example:
how do you harvest Calendula seeds?

Taxonomy
Calendula, Calendula officinalis, marigold, plants, unranked, anti-tumor, Pot Marigold, free encyclopedia, Calendula arvensis, cytotoxic, Field marigold, Medicinal flowers, genus Tagetes, Constituents, Calendula suffruticosa, bloom, oranges, Seeds.

Defination from the web:
Calendula should not be confused with other plants that are also known as marigolds, such as plants of the genus Tagetes, corn marigolds or marsh ... Plant pharmacological studies have suggested that Calendula extracts have anti-viral, anti-genotoxic and anti-inflammatory properties. ...