1. Vegetative blade segments deeply cut more than half way to the midvein, the entire blade lacerate.
S. dissectum(in part)
1. Vegetative blade segments finely to coarsely toothed.
2. Ultimate segments of blade ± uniform in size; vegetative blade segments finely toothed to ± entire; dissection of blade into segments extending to within 1 cm of apex at tips of blades.
3. Segments of vegetative blade rounded at base; symmetrically tapered to an often ± blunt or even rounded apex; larger segments mostly 9–17 mm long; margins nearly entire or finely and inconspicuously toothed.
3. Segments of vegetative blade usually (obliquely) asymmetrical and angular, cuneate to the apex; larger segments mostly 4–9 mm long; margins clearly finely dentate, especially visible in immature leaves.
2. Ultimate segments of blades variable in size, the apical segments much longer than the laterals; vegetative blade segments coarsely and ± irregularly toothed or cut; dissection of blade into segments stopping at ca. 1–2.5 cm from apex at tips of blades.
4. Larger (terminal) segments of vegetative blades lanceolate, acute, and strongly asymmetric at base; margins toothed to irregularly cut.
S. dissectum (in part)
4. Larger (terminal) segments of vegetative blades narrowly to broadly ovate, obtuse to rounded at apex, ± symmetrical at base; margins toothed but never lacerate.
All species found in Sceptridium
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. August 4, 2015. http://michiganflora.net/genus.aspx?id=Sceptridium.