. . . . . . . . . "Eristalis tenax" . . "Calendula officinalis" . . "John Flower. 2015. Eristalis tenax nectar plant Calendula officinalis. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/2379253> on 05 Apr 2018." . . . . "http://iNaturalist.org is a place where you can record what you see in nature, meet other nature lovers, and learn about the natural world." .