. . . . . . . . . "Papilio glaucus" . . "Cirsium horridulum" . . "Laura Clark. 2015. Papilio glaucus nectar plant Cirsium horridulum. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/1368536> 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." .