. . . . . . . . . "Pontia beckerii" . . "Sisymbrium altissimum" . . "Paul G. Johnson. 2016. Pontia beckerii insect host plant Sisymbrium altissimum. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/3670483> 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." .