. . . . . . . . . "Ceratina strenua" . . "Rudbeckia hirta" . . "Martin R. Lucas. 2017. Ceratina strenua nectar plant Rudbeckia hirta. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/8383282> 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." .