. . . . . . . . . "Trachusa timberlakei" . . "Cirsium occidentale" . . "edward_rooks. 2015. Trachusa timberlakei nectar plant Cirsium occidentale. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/1417463> 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." .