. . . . . . . . . "Polystichum aculeatum" . . "Dryopteris filix-mas" . . "Erwin Gruber. 2013. Polystichum aculeatum associated species with names lookup Dryopteris filix-mas. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/789140> 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." .