. . . . . . . . . "Gymnosporangium sabinae" . . "Pyrus communis" . . "arborsphere. 2016. Gymnosporangium sabinae host Pyrus communis. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/4219437> 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." .