. . . . . . . . . "Colias eurytheme" . . "Carduus pycnocephalus" . . "kevinhintsa. 2017. Colias eurytheme nectar plant Carduus pycnocephalus. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/6587098> 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." .