. . . . . . . . . "Letharia vulpina" . . "Abies concolor" . . "Justin. 2013. Letharia vulpina host Abies concolor. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/217979> 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." .