1. Indusia peltate (round and attached at the center); blades once-pinnate (except in Polystichum braunii) and conspicuously spiny toothed; fronds leathery and evergreen.
1. Indusia reniform, attached at the sinus; Blades once-pinnate (with the pinnae deeply lobed) to 3-pinnate, not conspicuously spiny toothed; fronds not leathery, evergreen or not.
All species found in Dryopteridaceae
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 20, 2018. https://www.michiganflora.net/family.aspx?id=Dryopteridaceae.